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Analysis of a freshwater benthic community with special reference to the chironomidae. Hamilton, Andrew Lloyd 1965

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AN ANALYSIS OF A FRESHWATER BENTHIC COMMUNITY WITH SPECIAL REFERENCE TO THE CHIRONOMIDAE  by ANDREW LLOYD HAMILTON B.A., U n i v e r s i t y o f Saskatchewan, 1959 M.A., U n i v e r s i t y o f Saskatchewan, 1961  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n t h e Department of Zoology  We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e required standard  THE UNIVERSITY OF BRITISH COLUMBIA November, 1965  In the  requirements  British  for  Columbia,  available mission  for  for  purposes his  presenting  I  an  reference  cation without  of  this  thesis  my w r i t t e n  Department  of  and  It for  November  the  the  is  of  Head  I  of  understood  financial  permission.  1965  partial  Columbia  at  the  Library  this  Zoology  23,  in  degree  study.  by  The U n i v e r s i t y o f B r i t i s h V a n c o u v e r 8, Canada Date  that  copying  be g r a n t e d  representatives.  thesis  advanced  agree  extensive  may  this  thesis  University  of  make  agree for  freely per-  scholarly  copying  shall  it  that  Department  that  gain  of  shall  further  my  fulfilment  not  or or be  by publi-  allowed  The U n i v e r s i t y of B r i t i s h Columbia FACULTY OF GRADUATE STUDIES PROGRAMME OF THE FINAL ORAL EXAMINATION FOR THE DEGREE OF DOCTOR OF PHILOSOPHY of ANDREW LLOYD HAMILTON B;A. U n i v e r s i t y of Saskatchewan, 1959 s  M,A,s U n i v e r s i t y of Saskatchewan^ 1961 TUESDAY, NOVEMBER 23 1965, AT 3:30 P.M. s  IN ROOM 3332, BIOLOGICAL SCIENCES BUILDING COMMITTEE IN CHARGE Chairman:  I , McTo Cowan  D„ H= C h i t t y I. E, E f f o r d W* S. Hoar  G. E. Rouse G„ G, Scudder N. J . Wilimovsky  Research Supervisor  I . E. E f f o r d  External Examiner:  S, D. Gerking  U n i v e r s i t y of Indiana Bloomington Indiana  AN ANALYSIS OF A FRESHWATER BENTHIC COMMUNITY WITH SPECIAL REFERENCE TO THE CHIRONOMIDAE ABSTRACT The macroscopic bottom fauna of Marion Lake, B r i t i s h Columbia, was i n v e s t i g a t e d from May 1963 to September, 1964. The primary object was to document seasonal d i f f e r e n c e s w i t h i n and between s p e c i f i c populations and to i n t e r p r e t these d i f f e r e n c e i n terms of the l i f e h i s t o r i e s of the species and t h e i r a v a i l a b i l i t y to a predator, rainbow trout. 3  A d e t a i l e d examination of the 51 species of Chironomidae known to occur i n the lake has shown that the e c o l o g i c a l c h a r a c t e r i s t i c s of many of the c l o s e l y r e l a t e d species are very d i f f e r e n t . Small species generally fed p r i m a r i l y on phytoplankton while, the larger species ate more d e t r i t u s and organic debris or other invertebrates, Predaceous species had more uniform d i s t r i b u t i o n s i n the lake than d i d herbivores or d e t r i t u s feeders, Most species of the subfamily Orthocladinae. emerged i n spring or f a l l , and grew r a p i d l y during the winter. The species of Chironominae and Tanypodinae u s u a l l y emerged during the spring and summer and grew very l i t t l e during the winter. Summer emerging Chironominae emerged l a t e r over deep water whereas the Tanypodinae. emerged at much the same time above a l l depths= Larvae which underwent frequent v e r t i c a l migrations had a higher m o r t a l i t y rate and were found more frequently i n the stomachs of rainbow trout than larvae which r a r e l y or never migrated, Many of the benthic organisms were not e f f e c t i v e l y u t i l i z e d by rainbow trout. Organisms which numerically c o n s t i t u t e d approximately 1.5% of the benthic fauna accounted for more than 50% of the food items found i n the trout stomachs, Large forms, such as the Odonata and Trichoptera and species which frequently moved o f f the bottom^ formed the bulk of the  food; small species and some of the species which were e n t i r e l y benthic were rare or absent i n the trout stomachs analyzed. This study has shown some of the advantages of working at the species l e v e l , Although studies at t h i s l e v e l are tedious and often necessitate a time consuming taxonomic study, the a d d i t i o n a l information i s l i k e l y to j u s t i f y the extra e f f o r t . The r e s u l t s of e c o l o g i c a l i n v e s t i g a t i o n s that are, not c a r r i e d out at the species l e v e l ignore, or at best o v e r s i m p l i f y , r e l a t i o n s h i p s that exist.„ Indeed, a comprehensive understanding o f for example, energy t r a n s f e r w i t h i n a community, i s impossible without a d e t a i l e d knowledge of the l i f e h i s t o r i e s of the species involved. 3  GRADUATE STUDIES F i e l d of Study: Advanced. Ecology F i s h e r i e s Biology and Management  D= H. C h i t t y N, J . Wilimovsky  Biology of Fishes  C, G.  Synoptic Oceanography  G„ L= Pickard  Quantitative Methods i n Zoology  P.  Lindsey  A. L a r k i n  SCH01Jtf-.SH.IPS AND AWARDS 1.958-59  - U n i v e r s i t y of Saskatchewan-Alumni Bursary  1960-61  - National Research Council Bursary  1961.-64  - National Research Council Studentships  1964  - McLean Fraser Memorial Fellowship  1.964  - American Society of I c h t h y o l o g i s t s and Herpetologists Stoye Award  1.964-65  - U n i v e r s i t y of B r i t i s h Columbia Graduate Fellowship  ii  ABSTRACT The m a c r o s c o p i c bottom fauna o f M a r i o n L a k e , B r i t i s h Columbia, was i n v e s t i g a t e d from May, 1963 t o September, 1964.  The p r i m a r y o b j e c t was t o document s e a -  s o n a l d i f f e r e n c e s w i t h i n and between s p e c i f i c  populations  and t o i n t e r p r e t these d i f f e r e n c e s i n terms o f t h e l i f e h i s t o r i e s o f t h e s p e c i e s and t h e i r a v a i l a b i l i t y t o a p r e d a t o r , rainbow t r o u t . A d e t a i l e d examination  o f t h e 51 s p e c i e s o f  Chironomidae known t o o c c u r i n the l a k e has shown t h a t t h e e c o l o g i c a l c h a r a c t e r i s t i c s o f many o f t h e c l o s e l y r e l a t e d species are very d i f f e r e n t . p r i m a r i l y on p h y t o p l a n k t o n  Small species g e n e r a l l y fed while the l a r g e r species ate  more d e t r i t u s and o r g a n i c d e b r i s o r o t h e r i n v e r t e b r a t e s . Predaceous s p e c i e s had more u n i f o r m d i s t r i b u t i o n s i n the l a k e than d i d h e r b i v o r e s and d e t r i t u s f e e d e r s .  Most s p e c i e s  o f the s u b f a m i l y O r t h o c l a d i i n a e emerged i n s p r i n g o r f a l l and grew r a p i d l y d u r i n g t h e w i n t e r . The s p e c i e s o f Chironominae and Tanypodinae u s u a l l y emerged d u r i n g t h e s p r i n g and summer and grew v e r y l i t t l e d u r i n g the w i n t e r .  Summer emerging  Chironominae emerged l a t e r o v e r deep water whereas t h e Tanypodinae emerged a t much t h e same time above a l l depths. L a r v a e which underwent f r e q u e n t v e r t i c a l m i g r a t i o n s had a h i g h e r m o r t a l i t y r a t e and were found more f r e q u e n t l y i n t h e  iii stomachs o f rainbow t r o u t than l a r v a e which r a r e l y o r never migrated. Many of the b e n t h i c organisms were not u t i l i z e d by rainbow t r o u t . c o n s t i t u t e d approximately  Organisms which n u m e r i c a l l y 1.5%  f o r more than 50% of the food stomachs.  effectively  of the b e n t h i c fauna accounted items found i n the t r o u t  L a r g e forms, such as the Odonata and  Trichoptera  and s p e c i e s which f r e q u e n t l y moved o f f the bottom, formed the b u l k of the f o o d ; s m a l l s p e c i e s and some of the  species  which were e n t i r e l y b e n t h i c were r a r e o r absent i n the t r o u t stomachs  analyzed. T h i s s t u d y has shown some of the advantages of  w o r k i n g at the s p e c i e s l e v e l .  A l t h o u g h s t u d i e s at t h i s  l e v e l are t e d i o u s and o f t e n n e c e s s i t a t e a time consuming taxonomic s t u d y , the a d d i t i o n a l i n f o r m a t i o n i s l i k e l y j u s t i f y the e x t r a e f f o r t .  The  to  r e s u l t s of e c o l o g i c a l i n v e s t i -  g a t i o n s t h a t are not c a r r i e d out at the s p e c i e s  level  i g n o r e , o r at b e s t o v e r s i m p l i f y , r e l a t i o n s h i p s t h a t e x i s t . Indeed, a comprehensive u n d e r s t a n d i n g  o f , f o r example,  energy t r a n s f e r w i t h i n a community, i s i m p o s s i b l e  without  a d e t a i l e d knowledge of the l i f e h i s t o r i e s of the  species  involved.  iv TABLE OF CONTENTS Page INTRODUCTION  1  DESCRIPTION OF THE STUDY AREA  4  LOCATION AND MORPHOMETRY  4  PHYSICAL AND CHEMICAL CONDITIONS  6  MATERIALS AND METHODS GENERAL  10 ,12  BOTTOM FAUNA  12  EMERGING INSECTS  16  PREDATION BY FISH  21  ECOLOGY OF THE MACROSCOPIC BOTTOM FAUNA  24  INTRODUCTION  25  RESULTS P o p u l a t i o n Dynamics 1. G e n e r a l 2. Chironomidae . . . (a) D e n s i t y . , (b) D i s t r i b u t i o n (c) Emergence Season Depth. (d) V e r t i c a l M i g r a t i o n s (e) Food ( f ) Growth 3. T r i c h o p t e r a 4. Odonata 5. Amphipoda (a) D e n s i t y and D i s t r i b u t i o n (b) Growth 6. A n n e l i d a 7. M o l l u s c a 8. M i s c e l l a n e o u s Taxa  26 26 26 28 28 32 35 35 35 39 41 45 48 49 50 50 50 52 53 53  V  Page U t i l i z a t i o n o f t h e Bottom Fauna by Rainbow T r o u t 1. D i u r n a l F e e d i n g B e h a v i o r 2. E s t i m a t e o f D a i l y Food Consumption . . . 3. A v a i l a b i l i t y o f t h e Bottom Fauna to Rainbow T r o u t DISCUSSION  54 54 56 67 70  METHODOLOGY  70  POPULATION DYNAMICS  73  UTILIZATION OF THE BOTTOM FAUNA  82  CONCLUSION  85  LITERATURE CITED  87  APPENDIX I . ADULT EMERGENCE AND LARVAL DENSITIES OF THE CHIRONOMIDAE  90  APPENDIX I I . TAXONOMY OF THE CHIRONOMIDAE OF MARION LAKE  (95)  vi LIST OF TABLES Table  Page I. II.  Mean monthly t e m p e r a t u r e s i n °C a t t h e Haney-spur 17 c l i m a t o l o g i c a l s t a t i o n . . . .  9  A n a l y s i s o f a water sample t a k e n a t s t a t i o n X d u r i n g A p r i l , 1963  11  E f f i c i e n c y of the standard s i e v i n g s c r e e n ( a p e r t u r e s = 0.56 mm. square) f o r chironomid larvae of various lengths  15  S e a s o n a l changes i n the d e n s i t i e s o f bottom organisms i n M a r i o n Lake, B r i t i s h Columbia  27  D e n s i t i e s o f t h e more numerous s p e c i e s of Chironomidae i n 1964; l a r v a e e s t i m ated w i t h an Ekman dredge i m m e d i a t e l y p r i o r t o t h e commencement o f a d u l t emergence and a d u l t s e s t i m a t e d w i t h emergence t r a p s  33  VI.  The numbers o f c h i r o n o m i d l a r v a e c o l l e c t e d i n emergence t r a p s  40  Vila.  Gut c o n t e n t s o f f o u r t h i n s t a r c h i r o n omid l a r v a e c o l l e c t e d i n M a r i o n L a k e , B r i t i s h Columbia  43  Gut c o n t e n t s o f f o u r t h i n s t a r c h i r o n omid l a r v a e c o l l e c t e d i n M a r i o n Lake, B r i t i s h Columbia  44  D i u r n a l d i f f e r e n c e s i n t h e average number o f f o o d organisms p e r t r o u t stomach  55  The r a t i o Number o f organisms i n t h e i n t e s t i n e s o f rainbow t r o u t Number o f organisms i n t h e stomachs o f rainbow t r o u t f o r s e v e r a l important food items  61  III.  IV.  V.  b.  VIII.  IX.  vii  Table  Page X. XI.  L o c a t i o n o f t h e major food items i n the stomachs of sample f i s h  63  Food i n t a k e o f rainbow t r o u t t o t h e bottom f a u n a  66  compared  viii LIST OF FIGURES Figure 1. 2. 3.  4. 5.  Page A e r i a l photo and c o n t o u r map o f M a r i o n L a k e , B r i t i s h Columbia  5  S e a s o n a l changes i n the t e m p e r a t u r e s a t v a r i o u s depths i n M a r i o n Lake  7  C u m u l a t i v e day-degree (mean temperature °C x days) c u r v e s f o r the Haney-spur 17 climatological station  10  Emergence t r a p used t o c o l l e c t insects  17  emerging  The d i g e s t i v e t r a c t of rainbow t r o u t i l l u s t r a t i n g t h e d i v i s i o n s used f o r food a n a l y s i s  22  S e a s o n a l changes i n l a r v a l d e n s i t i e s and a d u l t emergence of the Chironomidae  29  A comparison of l a r v a l d e n s i t y , a d u l t emergence and m o r t a l i t y of f o u r s p e c i e s o f Chironomidae  31  8.  D i s t r i b u t i o n p a t t e r n s of f o u r s p e c i e s of Chironomidae i n M a r i o n Lake  34  9.  S e a s o n a l p e r i o d s o f a d u l t emergence of the Chironomidae i n M a r i o n Lake  36  10.  Emergence p a t t e r n s of s i x s p e c i e s o f Chironomidae i n M a r i o n Lake  37  11.  D i e l m i g r a t i o n o f S e r g e n t i a sp. A  42  12.  Growth p a t t e r n s of f i v e s p e c i e s of c h i r o n o m i d l a r v a e i n M a r i o n Lake  46  Monthly changes i n the l e n g t h f r e q u e n c i e s of two s p e c i e s of Amphipoda i n M a r i o n Lake  51  6. 7.  13.  ix Figure 14.  Page D i u r n a l changes i n t h e c o n d i t i o n o f f o o d organisms from d i f f e r e n t p a r t s of t h e d i g e s t i v e t r a c t o f rainbow t r o u t . . . .  57  15.  D i u r n a l changes i n t h e number o f f o o d organisms p e r stomach  58  16.  D i u r n a l changes i n t h e average number, c o n d i t i o n and l o c a t i o n o f a d u l t c h i r o n o m i d s i n the d i g e s t i v e t r a c t o f rainbow t r o u t  65  A comparison o f t h e r e l a t i v e abundance of bottom organisms i n the stomachs o f rainbow t r o u t and i n the l a k e e x p r e s s e d as a c u m u l a t i v e p e r c e n t a g e . Organisms arranged i n o r d e r o f t h e i r r a t i o s o f % i n stomachs % i n lake„.,.  69  17.  X  ACKNOWLEDGEMENTS Dr. I . E . E f f o r d s u p e r v i s e d t h i s i n v e s t i g a t i o n and h e l p e d i n a m u l t i t u d e o f ways.  H i s many i d e a s and sug-  g e s t i o n s as w e l l as h i s a s s i s t a n c e i n t h e f i e l d  a r e much  appreciated. Messrs. Gordon D a v i e s , Jack M a t h i a s and t h e l a t e W i l l i a m Shearer very k i n d l y a s s i s t e d i n the c o l l e c t i o n of the f i e l d  data. The a s s i s t a n c e o f D r . D.R. O l i v e r o f t h e C e n t r a l  E x p e r i m e n t a l Farm, Ottawa i n t h e p r e p a r a t i o n o f t h e t a x o n omic s e c t i o n o f t h i s t h e s i s i s much a p p r e c i a t e d . H i s i d e n t i f i c a t i o n s o f many o f t h e Chironomidae and h i s numerous v a l u a b l e s u g g e s t i o n s have c o n t r i b u t e d g r e a t l y t o t h i s investigation. Dr. E.L. B o u s f i e l d o f t h e N a t i o n a l Research C o u n c i l , Ottawa v e r y k i n d l y i d e n t i f i e d t h e Amphipoda. D r s . W.S. Hoar, N.J. W i l i m o v s k y , G.G. Scudder and D.H. C h i t t y o f f e r e d many h e l p f u l s u g g e s t i o n s and c r i t i c i s m s r e g a r d i n g t h e s t u d y and t h e p r e p a r a t i o n o f t h e manuscript. The N a t i o n a l Research C o u n c i l o f Canada p r o v i d e d a s t u d e n t s h i p from 1961-64 and t h e U n i v e r s i t y o f B r i t i s h Columbia p r o v i d e d a graduate f e l l o w s h i p i n 1964-65.  The  f i e l d work was  s u p p o r t e d by a N a t i o n a l Research C o u n c i l  g r a n t t o the I n s t i t u t e of  Fisheries.  F i n a l l y I would l i k e to e x p r e s s thanks t o w i f e , B e t t y , f o r her h e l p , p a t i e n c e throughout the d u r a t i o n of t h i s  and  my  encouragement  investigation.  1 INTRODUCTION One o f t h e major concerns o f modern e c o l o g y i s the t r a n s f e r and u t i l i z a t i o n o f energy a t v a r i o u s l e v e l s i n the community.  I n v e s t i g a t i o n s t h a t a r e not c a r r i e d o u t a t  the s p e c i f i c l e v e l , i g n o r e o r o v e r s i m p l i f y r e l a t i o n s h i p s that e x i s t .  To i n v e s t i g a t e these r e l a t i o n s h i p s r e q u i r e s an  e v a l u a t i o n of the e c o l o g i c a l r o l e played species.  by i n d i v i d u a l  The p r e s e n t s t u d y i s an attempt t o demonstrate  that the increased  a c c u r a c y o f t h e r e s u l t s and t h e a d d i -  t i o n a l information obtained freshwater  from a d e t a i l e d a n a l y s i s of a  b e n t h i c community w i l l l i k e l y j u s t i f y t h e a d d i -  t i o n a l time and e f f o r t The  required.  i n t e r e s t t h a t p r e s e n t day e c o l o g i s t s have i n  the f l o w o f energy through communities i s l a r g e l y due t o the p i o n e e r  work o f Lindemann (1942).  H i s c l a s s i c paper on  the t r o p h i c dynamic a s p e c t o f e c o l o g y has s t i m u l a t e d e c o l o g i s t s t o c o n c e r n themselves w i t h t h e p r o d u c t i v i t y o r r a t e of energy t r a n s f e r i n b i o t i c communities r a t h e r than be content w i t h the determination  of standing  crop.  I t has been t r a d i t i o n a l f o r l i m n o l o g i s t s t o use the s t a n d i n g c r o p s o f food organisms t o p r e d i c t t h e p o t e n t i a l o f l a k e s as f i s h p r o d u c e r s , b u t as R i c k e r  (1945)  p o i n t s o u t t h i s measurement, though v a l u a b l e , i s not adequate.  The major r e a s o n f o r d e t e r m i n i n g  standing  crop  2 r a t h e r than p r o d u c t i v i t y i s t h a t t h e r e i s l i t t l e  difficulty  i n v o l v e d i n a c c u r a t e l y d e t e r m i n i n g s e a s o n a l changes i n the standing crop. R i c k e r (1946) c o n c l u d e s g a t o r s , Lundbeck (1926), B o r u t s k y  that only three  investi-  (1939), and M i l l e r  (1941)  had a c t u a l l y made s t u d i e s of the p r o d u c t i v i t y of the bottom fauna.  Other s t u d i e s were, i n h i s o p i n i o n , o n l y s t u d i e s of  standing crop.  Hayne and B a l l (1956) mention s e v e r a l sub-  sequent i n v e s t i g a t i o n s and showed i n t h e i r own  study that  s t a n d i n g crop c o u l d p r o v i d e a v e r y m i s l e a d i n g e s t i m a t e o f productivity.  They suggest  t h a t the p r o d u c t i v i t y o f  b e n t h i c fauna can be e s t i m a t e d i n the f o l l o w i n g t h r e e ways. F i r s t l y , by a d i r e c t study of the dynamics of the i t s e l f ; t h i s i s the approach used by the e a r l i e r g a t o r s r e f e r r e d t o above.  fauna investi-  S e c o n d l y , the m e t a b o l i c r e q u i r e -  ments o f the p r e d a t o r s p e c i e s can be e s t i m a t e d and  this  v a l u e i n t u r n used t o c a l c u l a t e the amount o f f o o d r e q u i r e d t o s a t i s f y these r e q u i r e m e n t s ; (1954, 1962)  A l l e n (1951) and  Gerking  have used t h i s approach to e s t i m a t e b e n t h i c  productivity. 1946), s u g g e s t s  The  t h i r d method, proposed by R i c k e r (1937,  t h a t the t o t a l amount of food p a s s i n g  through the f i s h p o p u l a t i o n be e s t i m a t e d by s t u d y i n g the f o o d h a b i t s o f f i s h and the r a t e of c l e a r a n c e o f the stomach c o n t e n t s ; t h i s q u a n t i t y i s then compared w i t h the q u a n t i t y of the b e n t h i c prey p o p u l a t i o n to a r r i v e at an  3 estimate of benthic p r o d u c t i v i t y .  The two l a t t e r  approaches a r e more i n d i r e c t and do not t a k e i n t o account e i t h e r the energy t r a n s f e r t h a t o c c u r s w i t h i n the b e n t h i c fauna o r t h e energy l o s t through  respiration.  A number o f a s p e c t s o f t h e b e n t h i c fauna which a r e p e r t i n e n t t o the measurement o f p r o d u c t i v i t y have been i n v e s t i g a t e d d u r i n g the course o f t h i s s t u d y .  I n every  c a s e t h e d i f f e r e n c e s between what o f t e n were c l o s e l y r e l a t e d s p e c i e s were too l a r g e t o s a f e l y i g n o r e . The r e s e a r c h r e p o r t e d h e r e i n was undertaken on Marion L a k e , B r i t i s h Columbia and i s p a r t o f a r e s e a r c h program b e i n g conducted by D r . I . E. E f f o r d on the product i v i t y o f v a r i o u s t r o p h i c l e v e l s i n the l a k e community. R e s u l t s o f t h e d e t a i l e d taxonomic s t u d y o f t h e Chironomidae, a n e c e s s a r y  p r e r e q u i s i t e to t h i s  investi-  g a t i o n , a r e g i v e n i n Appendix I I . T a b l e s o f l a r v a l d e n s i t y and a d u l t emergence o f t h i s s u b f a m i l y a r e p r e s e n t e d i n Appendix I .  4  DESCRIPTION OF THE STUDY AREA LOCATION AND MORPHOMETRY Marion Lake ( a l s o known as Jacob's Lake) i s s i t u a t e d a p p r o x i m a t e l y 50 k i l o m e t r e s (31 m i l e s ) e a s t o f Vancouver i n a r e s e a r c h f o r e s t o p e r a t e d by t h e U n i v e r s i t y o f B r i t i s h Columbia.  I t l i e s a t an a l t i t u d e o f 304 metres  (1000 f e e t ) and i t s l o c a t i o n i s 49Q19'N, 122033'W. The a x i s o f t h e l a k e and t h e v a l l e y i n which i t i s s i t u a t e d both l i e i n a n o r t h - s o u t h d i r e c t i o n .  The p r e v a i l i n g winds  a r e from t h e s o u t h . The s h a l l o w u n i f o r m n a t u r e o f t h e l a k e i s i l l u s t r a t e d i n F i g u r e 1.  I r r e g u l a r i t i e s i n t h e bottom p r o f i l e  are almost e n t i r e l y due t o t h e presence o f s p r i n g s , which a l o n g w i t h s e v e r a l i n t e r m i t t e n t streams and one l a r g e i n l e t stream a r e r e s p o n s i b l e f o r t h e i n f l o w i n t o t h e l a k e . The s i n g l e outle*t stream a t t h e s o u t h end o f t h e l a k e d r a i n s i n t o the North A l o u e t t e R i v e r .  A t s t a n d a r d water  l e v e l , c a l c u l a t e d from depth measurements t a k e n A p r i l 13, 1963, t h e a r e a o f t h e l a k e i s 13.3 h e c t a r e s (32.9 a c r e s ) and t h e maximum and mean depths a r e 6.0 and 1.8 metres respectively.  The d r a i n a g e a r e a i s 6.5 square k i l o m e t r e s .  The s i z e o f t h i s a r e a when c o n s i d e r e d i n c o n j u n c t i o n w i t h the amount o f r a i n f a l l and t h e sharp r e l i e f o f t h e t e r r a i n a d j a c e n t t o t h e l a k e e x p l a i n s t h e r a p i d and o f t e n l a r g e  6 f l u c t u a t i o n s i n the dimensions of the l a k e .  I n summer i t  i s not uncommon t o r e c o r d r e a d i n g s 0.5 metres below t h e "standard"  l e v e l whereas w i n t e r water l e v e l s a r e u s u a l l y  h i g h e r than t h e " s t a n d a r d " .  D u r i n g p e r i o d s o f heavy r a i n -  f a l l t h e depth o f t e n i n c r e a s e s by a p p r o x i m a t e l y hour.  Subsequent d e c r e a s e s  10 cm. p e r  i n water l e v e l are e q u a l l y  dramatic. The  bottom sediments a r e u n i f o r m , c o n s i s t i n g  p r i m a r i l y o f brown f l o c c u l a n t oozes and l e s s e r amounts o f plant debris.  The p r o p o r t i o n o f d e b r i s i s c o n s i d e r a b l y  h i g h e r near t h e i n l e t and a l o n g t h e s h o r e .  Significant  amounts o f c l a y , sand and g r a v e l o c c u r i n and a d j a c e n t t o the i n l e t and o u t l e t streams.  PHYSICAL AND CHEMICAL CONDITIONS I n w i n t e r t h e l a k e was i s o t h e r m a l on a l l o c c a s i o n s t h a t t e m p e r a t u r e s were r e c o r d e d . periods of i c e cover.  There were i n t e r m i t t e n t  Deeper p a r t s o f t h e l a k e a r e f o r t h e  most p a r t weakly s t r a t i f i e d  i n t h e summer, w i t h t h e thermo-  c l i n e b e i n g i n v a r i a b l y much s h a r p e r near s p r i n g s .  The  temperature i n t h e main p a r t o f t h e l a k e a t one, t h r e e and f i v e metres depth a r e r e c o r d e d  i n Figure 2 f o r the period  from A p r i l 1963 t o August 1964. The water t e m p e r a t u r e s were, on t h e a v e r a g e , s e v e r a l degrees lower i n 1964 than i n 1963, s u g g e s t i n g t h a t c o n s i d e r a b l e d i f f e r e n c e s i n  8  weather c o n d i t i o n s had o c c u r r e d .  Data from t h e Haney -  s p u r 17 c l i m a t o l o g i c a l s t a t i o n l o c a t e d 3 k i l o m e t r e s  south  of t h e l a k e v e r i f y t h i s (Table I , F i g u r e 3 ) . T r a n s p a r e n c y as measured w i t h a s t a n d a r d  20 cm.  d i a m e t e r ) s e c c h i d i s c v a r i e d from 3.6 t o 6 metres, t h e maximum depth o f t h e l a k e . transparent  The water was g e n e r a l l y more  d u r i n g t h e w i n t e r months.  A n a l y s i s o f l a k e water samples by t h e G e n e r a l Testing Laboratories  Company L i m i t e d , 325 Howe S t r e e t ,  Vancouver, has shown t h e l a k e t o be low i n d i s s o l v e d nutrients.  The r e s u l t s o f one such a n a l y s i s a r e p r e s e n t e d  i n Table I I . The pH o f t h e l a k e w a t e r v a r i e d between 5.9 and 7.4.  I n summer most o f t h e r e a d i n g s  were a p p r o x i m a t e l y  7.0 w h i l e i n w i n t e r they were u s u a l l y n e a r e r 6.5 The l e v e l o f d i s s o l v e d oxygen was g e n e r a l l y high.  However, i n t h e summer months r e a d i n g s  as low as  0.5 c c / 1 were r e c o r d e d f o r w a t e r samples t a k e n near t h e bottom i n deeper p a r t s o f t h e l a k e .  Table I.  Mean monthly temperatures i n °C a t t h e Haney - s p u r 17 c l i m a t o l o g i c a l station.  Jan.  Feb.  Mar.  A p r . May  J u n . J u l . Aug.  Sep.  O c t . Nov.  Dec.  Mean  1963  -0.6  7.8  5.0  7.2  12.8  13.3  14.4  17.2  16.7  10.6  5.0  4.4  9.4  1964  2.2  3.3  3.9  5.6  9.4  12.8  15.0  15.0  12.8  11.7  3.9  -1.1  7.8  co  •* 10  J  F  M  A  M  J  J  A  S  O  N  D  F i g u r e 3 - C u m u l a t i v e day-degree (mean temperature °C x days) c u r v e s f o r t h e Haney - s p u r 17 c l i m a t o logical station.  11 T a b l e I I . A n a l y s i s of a water sample t a k e n a t S t a t i o n X d u r i n g A p r i l 1963. Constituent Silica Iron  Parts Per 3.5  (S;^) (Fe 0 )  Calcium  3  0.2  (CaO)  2.6  2  Magnesium  (MgO) (PO4)  Phosphates Nitrates  (N0 ) 3  l e s s than  0.1 0.15 0.1  3  1.7  Chlorides (Cl)  0.8  Bicarbonates  0.5  Carbonates  nil  P o t a s s i u m (IC^O)  0.3  Sodium (Na 0)  0.7  Sulphates  (S0 )  2  Million  12 MATERIALS AND METHODS GENERAL T h i s s t u d y e n t a i l e d an i n v e s t i g a t i o n o f a l l t h e m a c r o s c o p i c bottom organisms i n t h e l a k e , w i t h p a r t i c u l a r r e f e r e n c e t o t h e two most common t a x a , t h e Chironomidae and Amphipoda.  Sampling was done t o document s e a s o n a l changes  in s p e c i f i c populations.  These changes were then  inter-  preted w i t h r e f e r e n c e t o the l i f e h i s t o r i e s of the species and  t h e i r a v a i l a b i l i t y t o a p r e d a t o r , rainbow t r o u t . A t o t a l o f n i n e s t a t i o n s were s e l e c t e d f o r i n t e n -  s i v e s a m p l i n g o f t h e bottom fauna and emerging i n s e c t s . The  l o c a t i o n s o f t h e s e s i t e s ( F i g . 1) were s t r a t i f i e d so  t h a t t h e number o f s t a t i o n s i n each depth zone was a p p r o x i mately p r o p o r t i o n a l t o the percentage of the t o t a l occupied  area  by t h a t zone.  BOTTOM FAUNA 9  B e n t h i c organisms were c o l l e c t e d w i t h a 225 cm' Ekman dredge.  Whenever p o s s i b l e one d r e d g i n g was taken a t  each s t a t i o n e v e r y two weeks.  The s a m p l i n g program was  c o n t i n u e d from May 2, 1963 t o September 2, 1964 and was i n t e r r u p t e d o n l y when w i n t e r road c o n d i t i o n s o r i c e cond i t i o n s on t h e l a k e made t h i s n e c e s s a r y .  The samples were  13 washed i n 15 i n c h d i a m e t e r  g a l v a n i z e d t u b s , t h e bottoms o f  which had been r e p l a c e d w i t h b r a s s s c r e e n o f 30 meshes p e r l i n e a r i n c h ( a p e r t u r e s = 0.56 mm.  square).  From May 2,  1964 u n t i l September 2, 1964 the samples from s t a t i o n s I I and XI were washed i n an a d d i t i o n a l washing t u b w i t h a f i n e r mesh s c r e e n  ( a p e r t u r e s = 0.18 mm.  square) t o d e t e r m i n e t h e  p e r c e n t a g e o f the fauna p a s s i n g through  t h e c o a r s e r mesh  and t h e r e b y c a l c u l a t e c o r r e c t i o n f a c t o r s t o be used t o estimate a c t u a l d e n s i t i e s .  The washed samples were t r a n s -  f e r r e d t o 24 o z . j a r s f o r t r a n s p o r t and i n i t i a l  storage.  F o r m a l i n was added t o t h e j a r s t o f i x t h e specimens and l a t e r t h e samples were p l a c e d i n w h i t e t r a y s f o r s o r t i n g . The a n i m a l s were p i c k e d out w i t h f o r c e p s and p r e s e r v e d in= v i a l s c o n t a i n i n g 70% e t h a n o l . The samples were a n a l y z e d w i t h the a i d o f a d i s s e c t i n g m i c r o s c o p e and when n e c e s s a r y w i t h a compound m i c r o s c o p e as w e l l .  I n o r d e r t o d e t e r m i n e t h e growth p a t -  t e r n o f each s p e c i e s they were s e p a r a t e d and each i n d i v i d u a l measured w i t h an o c u l a r micrometer.  The u s u a l method o f  measurement was t o r e c o r d t h e t o t a l body l e n g t h , however, i n the case o f the o l i g o c h a e t e s body w i d t h was  recorded  instead. Chironomids were t h e o n l y a n i m a l s where major d i f f i c u l t i e s were encountered i n s e p a r a t i n g s p e c i e s . U s u a l l y t h e g r o s s e x t e r n a l c h a r a c t e r s , p a r t i c u l a r l y t h e form  14 of t h e eye s p o t s and a n a l g i l l s were s u f f i c i e n t t o s e p a r a t e species.  Temporary s l i d e s were made o f d o u b t f u l specimens  to v e r i f y p r e l i m i n a r y i d e n t i f i c a t i o n s .  Careful manipulation  of t h e c o v e r s l i p u s u a l l y p r o v i d e d a s a t i s f a c t o r y view o f such d i a g n o s t i c p a r t s as t h e l a b i a l p l a t e and antennae. As i n d i c a t e d i n T a b l e I I I dredge samples s i e v e d through a 30 mesh p e r l i n e a r i n c h s c r e e n ( a p e r t u r e s = 0.56 mm. square) d i d not a d e q u a t e l y sample c h i r o n o m i d l a r v a e l e s s t h a n 9 mm. i n l e n g t h .  Members o f t h e s u b f a m i l i e s  Chironominae  and O r t h o c l a d i n a e tended t o pass through t h e s c r e e n more r e a d i l y t h a n h e a v i e r b o d i e d Tanypodinae  o f t h e same l e n g t h  (Table I I I ) . j6nasson  (1955) found t h a t head c a p s u l e w i d t h was  the c r i t i c a l f a c t o r g o v e r n i n g whether an a n i m a l would through t h e s c r e e n .  pass  However, i n t h i s experiment some a n i -  mals w i t h a head d i a m e t e r not e x c e e d i n g 0.4 mm. compared t o a mesh a p e r t u r e o f 0.56 mm. square were sampled w i t h almost 100% e f f i c i e n c y .  These u n e x p e c t e d l y h i g h v a l u e s may be due  to t h e l a r g e amount o f d e b r i s p r e s e n t i n t h e sample r e s i dues. There i s some e v i d e n c e t h a t t h e s m a l l mesh s i e v e ( a p e r t u r e = 0.18 mm. square) i s n o t adequate f o r t h e e a r l i e r i n s t a r s o f some s p e c i e s o f c h i r o n o m i d s .  The s m a l l e s t l a r v a e  c o l l e c t e d u s i n g t h i s s c r e e n were 1.5 mm.  l o n g whereas a 1.1  Table I I I .  E f f i c i e n c y of the standard s i e v i n g screen (aperture f o r chironomid larvae of various lengths.  !  Tanypodinae Percent Number Number retained retained Length of i l a r v a e [ r e t a i n e d by by 0.56 mm. by 0.56 mm. mm. J both meshes sieve sieve  = 0.56 nun. square)  Chironominae p l u s O r t h o c l a d i n a e Number Percent Number retained retained r e t a i n e d by by 0.56 mm. by 0.56 mm. b o t h meshes sieve sieve  2  j  136  21  15.4  580  60  10.3  3  !  306  133  43.5  1314  439  33.4  4  !  235  178  75.7  784  378  48.2  5  j  108  83  76.9  327  237  72.5  6  !  39  26  66.7  293  243  82.9  7  |  12  11  91.7  172  156  90.7  8  i  39  88.6  9+  !  210  97.2  5  1  0  100%  0  100%  44 216  16  mm.  l o n g l a r v a o f P a g a s t i e l l a s p . A was found i n s i d e a  l a r v a o f Ablabesmyia  monilis.  The e f f i c i e n c y o f t h e Ekman dredge and problems a s s o c i a t e d w i t h s a m p l i n g what p r o b a b l y a r e non-randomly d i s t r i b u t e d p o p u l a t i o n s were not i n v e s t i g a t e d .  I t was  thought t h a t such e r r o r s were minor and where p r e s e n t , would tend t o a c t e q u a l l y on d i f f e r e n t age groups so t h a t r e s u l t s would a t l e a s t be  comparable.  Food p r e f e r e n c e s o f t h e v a r i o u s s p e c i e s of c h i r onomids were i n v e s t i g a t e d by examining s l i d e s of c l e a r e d specimens.  A l l the techniques of s l i d e p r e p a r a t i o n out-  l i n e d under t h e taxonomic  s e c t i o n were u s a b l e , however.;  specimens f i r s t macerated  i n KOH were p a r t i c u l a r l y  to t h i s type o f a n a l y s i s .  suited  The v o l u m e t r i c percentage of t h e  t o t a l food c o n t e n t was e s t i m a t e d f o r each food i t e m .  This  measurement was s i m p l e r t h a n making counts of i n d i v i d u a l s and because o f l a r g e v a r i a t i o n s i n t h e s i z e s of d i f f e r e n t items i t i s p r o b a b l y more u s e f u l .  EMERGING INSECTS Most o f the a d u l t s , pupae and p u p a l e x u v i a e  col-  l e c t e d d u r i n g the c o u r s e o f t h i s s t u d y were t a k e n i n submerged f u n n e l t r a p s ( F i g . 4 ) , one o f which was l o c a t e d a t each o f the s t a t i o n s .  The t r a p s were u s u a l l y emptied  every  10 cm. Figure  4 -  Emergence t r a p u s e d t o  collect  emerging  insects,  18 two  t o f o u r days.  T h i s t r a p works on t h e same  principle  as t h a t f i r s t d e s c r i b e d by R o s s o l i m o (Mundie, 1956) and l a t e r modified  by s e v e r a l i n v e s t i g a t o r s i n c l u d i n g B r u n d i n  (1949), Jbnasson (1954), Mundie (1956) and S u b l e t t e and Dendy (1958).  The model used i n t h i s i n v e s t i g a t i o n i n c o r -  p o r a t e s most o f what t h e a u t h o r c o n s i d e r s as t h e major advantages o f t h e e a r l i e r t y p e s . are more t r a n s p a r e n t  The v i n y l p l a s t i c  funnels  and much e a s i e r t o keep c l e a n than  screen o r polyethylene  p l a s t i c , hence r e d u c i n g t h e l i k e l i -  hood of pupae a v o i d i n g t h e t r a p because o f t h e shadow c a s t by i t . The s m a l l f u n n e l i n t h e mouth o f t h e j a r keeps water soaked specimens from b e i n g l o s t and a l s o the escape o f some o f t h e c h i r o n o m i d trap.  prevents  larvae that enter the  A d d i t i o n a l advantages t h a t many o f t h e e a r l i e r models  d i d n o t have i n c l u d e ruggedness, compactness and ease o f construction. The  t r a p s were c o n s t r u c t e d  as f o l l o w s :  transparent  v i n y l p l a s t i c 0.020 o f an i n c h t h i c k was used f o r t h e f u n n e l s which had a base d i a m e t e r o f 35.8 cm. and covered an a r e a o f 0.1 square metres.  A l l seams were heat s e a l e d .  E i g h t ounce j a r s were used as c o l l e c t i n g v e s s e l s . were a t t a c h e d  They  t o t h e f u n n e l by means o f t h e i r b a k e l i t e l i d s ,  each o f which had a h o l e 4.5 cm. i n d i a m e t e r c u t i n i t w i t h a lathe.  A g l a s s j a r w i t h t h e same o u t s i d e d i a m e t e r as  t h a t o f t h e b a k e l i t e l i d s was f o r c e d through each f u n n e l  19 a f t e r the s m a l l e r ends o f the f u n n e l had been immersed i n near b o i l i n g w a t e r .  A l i p was made on each o f the s m a l l  f u n n e l s by p l a c i n g the w a t e r - h e a t e d p l a s t i c on a f l a t  sur-  f a c e and t h e n p r e s s i n g the mouth o f the emergence j a r s o v e r each f u n n e l .  T h i s was b e s t a c c o m p l i s h e d by r o t a t i n g the  j a r s as p r e s s u r e was a p p l i e d .  A s t a i n l e s s s t e e l hose  was used to a t t a c h the b a k e l i t e l i d t o the f u n n e l .  clamp Four  l e a d w e i g h t s were clamped on the lower r i m of the l a r g e f u n n e l t o g i v e the t r a p n e g a t i v e bouyancy. In o p e r a t i o n the t r a p was suspended from a s t y r o foam f l o a t by means of a heavy n y l o n l i n e . i n t u r n anchored t o t h e bottom.  The f l o a t  was  The c o l l e c t i n g j a r was  f i l l e d about h a l f f u l l o f w a t e r , l e a v i n g an a i r space i n which a d u l t s c o u l d emerge.  A s m a l l p i e c e of non-absorbent  s t y r o f o a m p l a c e d i n each j a r p r o v i d e s something f o r the a d u l t s t o s t a n d on and h e l p s p r e v e n t t h e i r becoming  water  logged. To c o l l e c t a sample the j a r was unscrewed h o l d i n g i t under w a t e r . by hand, t h e n l i f t e d w i t h a numbered l i d . jar.  Specimens  while  The mouth of the j a r was c o v e r e d  out of the w a t e r , i n v e r t e d and  capped  The t r a p was then r e s e t u s i n g a new  c o l l e c t e d i n t h i s manner were e i t h e r  first  f i x e d w i t h f o r m a l i n and t h e n p r e s e r v e d i n 70% e t h a n o l o r p r e s e r v e d d i r e c t l y i n 70% e n t h a n o l .  20 The  " e f f i c i e n c y " o f t h e t r a p was e s t i m a t e d f o r  most o f t h e c h i r o n o m i d benthic  s p e c i e s by comparing the d e n s i t y o f  l a r v a e as c a l c u l a t e d from d r e d g i n g s t a k e n immedi-  a t e l y p r i o r t o emergence w i t h t h e c a l c u l a t e d d e n s i t y o f emerging a d u l t s .  T h i s c a l c u l a t e d " e f f i c i e n c y " i s not com-  p l e t e l y adequate because i t does n o t take the l a r v a l and pupal m o r t a l i t y that occurs As a r e s u l t t h i s e s t i m a t e the t r u e e f f i c i e n c y .  i n the i n t e r v a l i n t o account.  i s almost c e r t a i n l y lower than  The o n l y way t o r e l i a b l y t e s t t h e  e f f i c i e n c y o f an emergence t r a p i s t o conduct e x p e r i m e n t s under c o n t r o l l e d l a b o r a t o r y c o n d i t i o n s , however, r e s u l t s obtained  by t h e method d e s c r i b e d above s t r o n g l y suggest  t h a t t h e a c t u a l e f f i c i e n c i e s v a r y f o r d i f f e r e n t groups and different species.  C a l c u l a t e d " e f f i c i e n c i e s " f o r t h e major  groups w i t h i n t h e Chironomidae were Tanypodinae 36.6%, Orthocladinae  29.5% and Chironominae 37.9% ( C h i r o n o m i n i  17.2%, T a n y t a r s i n i 6 8 . 0 % ) .  The e s t i m a t e d  d e n s i t i e s of  emerging a d u l t s o f t h e more common s p e c i e s a r e compared i n T a b l e V w i t h the number o f f o u r t h i n s t a r l a r v a e e s t i m a t e d t o be p r e s e n t  p r i o r t o emergence. The  lowest " e f f i c i e n c y " , 9.7%,was r e c o r d e d f o r  the s p e c i e s P o l y p e d i l i u m t r i t u m and P o l y p e d i l i u m s i m u l a n s which were c o n s i d e r e d the l a r v a e . estimated  t o g e t h e r because of t h e s i m i l a r i t y o f  On t h e o t h e r hand t h e t r a p ' s " e f f i c i e n c y " was  a t o v e r 100% f o r a few o f t h e s p e c i e s .  This  21 paradox can r e s u l t from pupae s e e k i n g s h e l t e r i n the t r a p as i s a p p a r e n t l y the case w i t h T a n y t a r s u s s p . B o r i t can be a r e s u l t o f inadequate s a m p l i n g o f the l a r v a e .  F o r example,  the l a r v a e o f Z a v r e l i a s p . A and S t e m p e l l i n a b a u s e i a r e t o o s m a l l t o be a d e q u a t e l y sampled  by the methods used.  w i s e l a r v a e o f C r i c o t o p u s t r i c i n c t u s and Corynoneura  Likesp. A  were c o l l e c t e d i n t h e emergence t r a p s but were never t a k e n i n dredgings. PREDATION BY FISH Monofilament n y l o n g i l l n e t s were used t o c o l l e c t the f i s h used f o r a n a l y s i s of t h e i r f e e d i n g r a t e s . were s e t f o r a 24 hour p e r i o d from 3 P.M. August to 3 P.M. August  11, 1963.  Nets  10, 1963  They were emptied e v e r y two  hours and an i n c i s i o n was made i n t h e body w a l l o f each b e f o r e b e i n g p l a c e d d i r e c t l y i n 10% f o r m a l i n . to h a l t d i g e s t i v e p r o c e s s e s .  fish  T h i s was done  The d i g e s t i v e t r a c t of each  f i s h examined was d i v i d e d i n t o s i x p a r t s as i n d i c a t e d i n F i g u r e 5.  The numbers o f each p r e y s p e c i e s o c c u r r i n g p e r  s e c t i o n were r e c o r d e d and t h e c o n d i t i o n o f each f o o d organism was l i s t e d as i n t a c t , d i s i n t e g r a t i n g o r e x o s k e l e t o n only.  As i s o u t l i n e d i n the s e c t i o n on u t i l i z a t i o n o f t h e  bottom fauna t h i s i n f o r m a t i o n was t h e n used t o e s t i m a t e t h e d a i l y food r a t i o n o f t h e rainbow t r o u t .  Kokanee salmon and  rainbow t r o u t c o l l e c t e d a t o t h e r times o f the y e a r were not examined, f i r s t l y , because o f t h e l e n g t h o f time r e q u i r e d  23  f o r a d e t a i l e d f o o d a n a l y s i s and s e c o n d l y , because of the inadequate s i z e s of the samples.  24  ECOLOGY OF THE MACROSCOPIC BOTTOM FAUNA  25  INTRODUCTION I n t h i s s t u d y , as w i t h any e c o l o g i c a l  investiga-  t i o n , the problem of where t o p l a c e the emphasis was mount.  A broad but s u p e r f i c i a l e x a m i n a t i o n o f the  f a u n a a t perhaps the f a m i l y l e v e l would very s a t i s f a c t o r y r e s u l t s .  parabottom  l i k e l y not l e a d t o  On the o t h e r hand, a d e t a i l e d  a n a l y s i s of the dynamics o f a l l the components o f the b o t tom f a u n a would r e q u i r e a p r o h i b i t i v e amount of time and effort.  The compromise a r r i v e d a t has been t o t r e a t the  two n u m e r i c a l l y dominant groups, the Chironomidae  and  Amphipoda i n c o n s i d e r a b l e d e t a i l and t o examine the remaini n g c o n s t i t u e n t s o f the bottom fauna i n a more s u p e r f i c i a l manner.  I t s h o u l d be n o t e d , however, t h a t abundance i s  o n l y an i n d i c a t o r of the importance of a s p e c i e s i n the dynamics o f a community. T r i c h o p t e r a may,  Large p r e d a t o r y Odonata and  d e s p i t e t h e i r low d e n s i t y , be major  of m o r t a l i t y i n the remainder o f the bottom f a u n a .  causes They i n  t u r n are o f t e n much more i m p o r t a n t as a f i s h food t h a n t h e i r d e n s i t y would  indicate.  The r e l a t i o n s h i p s t h a t e x i s t w i t h i n a l a k e - b o t t o m community a r e complex and v a r i e d .  There a r e p l a n k t o n f e e d -  e r s , d e t r i t u s f e e d e r s and s p e c i e s t h a t p r e y on o t h e r bottom organisms.  Some f e e d on o n l y one t y p e of f o o d and o t h e r s on  a variety.  The f o o d i n t a k e i s i n f l u e n c e d by  availability  and a t l e a s t i n some c a s e s by the age and s i z e of the  26 individual. Bottom organisms a r e not a l l e q u a l l y a c c e s s i b l e to f i s h .  F o r i n s t a n c e , a n n e l i d s , which l i v e b u r i e d i n t h e  bottom s e d i m e n t s , a r e r a r e l y consumed by f i s h B a l l , 1956).  (Hayne and  The f a c t t h a t some organisms a r e p l a n k t o n i c  d u r i n g hours o f d a r k n e s s and a t c e r t a i n s t a g e s o f t h e i r l i f e h i s t o r i e s makes them more a v a i l a b l e t o most f i s h counterparts  t h a t a r e always b e n t h i c .  organism i s important.  than  The s i z e of t h e  L a r g e forms such as Odonata n a i a d s ,  T r i c h o p t e r a l a r v a e and a d u l t amphipods o f t e n s u f f e r a h i g h e r m o r t a l i t y due t o f i s h p r e d a t i o n than s m a l l e r forms. In t h i s s e c t i o n a r a t h e r d e t a i l e d treatment of the s e a s o n a l presented.  changes o c c u r r i n g a t t h e p o p u l a t i o n l e v e l i s Many o f t h e r e s u l t s a r e i n t e r p r e t e d i n l i g h t o f  s p e c i f i c l i f e h i s t o r i e s , i n t e r s p e c i f i c p r e d a t i o n and f a c t o r s o f t h e p h y s i c a l environment.  RESULTS POPULATION DYNAMICS 1.  General S e a s o n a l changes i n t h e d e n s i t i e s o f bottom  organisms o c c u r r i n g i n M a r i o n Lake a r e p r e s e n t e d IV.  i n Table  A l l v a l u e s a r e c o r r e c t e d f o r l o s s due t o t h e s i e v i n g  technique;  however, c h i r o n o m i d  l a r v a e l e s s t h a n 2.0  mm.  T a b l e IV. S e a s o n a l changes i n t h e d e n s i t i e s o f bottom organisms i n Marion L a k e , B r i t i s h Columbia ( c h i r o n o m i d s l e s s t h a n 2.0 mm. l o n g not i n c l u d e d ) . MEAN CORRECTED DENSITY PER SQUARE METRE Sep-Oct Nov-Dec Jan-Feb Mar-Apr May-Jun J u l - A u g Average Average 1963 1963 1964 1964 1964 1964 Number P e r c e n t Number o f D r e d g i n g s Oligochaeta Lumbriculidae Tubificidae Other O l i g o c h a e t a Hirudinea Hirudidae Glossiphoniidae Mollusca Pisidium Helisoma Amphipoda H y a l e l l a azteca Crangonyx richmondensis occidentalis Odonata Anisoptera Zygoptera Trichoptera Psychomyiidae Phryganeidae Other T r i c h o p t e r a Chironomidae Tanypodinae Orthocladinae Chironominae Ceratopogonidae Others Total  45  36  18  27  36  36  114 832 242  104 1290 135  101 244 67  72 1067 26  96 870 31  72 432 11  93 789 85  1.0 8.4 0.9  6 57  6 52  47  15  2 41  104  2 53  0.6  596 56  695 51  918 42  780 49  690 63  652 57  722 53  7.7 0.6  1204  1311  1146  866  624  479  938  10.0  125  104  79  71  22  371  129  1.4  2 1  1 4  7 10  2 6  4 2  -  12 2  32 5 4  30 2 -  20 2  19 5 1  16 48 -  22 10 1  0.2 0.1  404 494 1034 6 16 5208  571 2818 4053 47 10 11293  1017 4533 6866 40 20 15169  527 1870 4286 21 15 9695  1016 839 3838 36 1 8200  955 624 3163 54 8 7046  748 1863 3873 34 12 9435  7.9 19.7 41.1 0.4 0.1  --  3 5  +  + +  +  28 l o n g a r e not i n c l u d e d i n t h e s e a d j u s t e d e s t i m a t e s .  The c a l -  c u l a t e d maximum d e n s i t y o f 15,169 p e r square metre o c c u r r e d i n the January-February  period.  T h i s corresponds  w i n t e r maximum o f t e n r e p o r t e d i n t h e l i t e r a t u r e 1926;  Rawson, 1930).  with the (Lundbeck,  However, s i n c e l i t t l e o r no r e p r o d u c -  t i o n i s o c c u r r i n g i n t h e w i n t e r t h i s apparent maximum can o n l y be i n t e r p r e t e d as an a r t i f a c t o f t h e s a m p l i n g  system.  In f a c t t h i s maximum was, i n M a r i o n Lake a t l e a s t , almost e n t i r e l y a r e s u l t o f changes i n t h e c h i r o n o m i d  population.  I t so happens t h a t most o f t h e more abundant s p e c i e s o f chironomids  were s m a l l w i n t e r - g r o w i n g  .  s p e c i e s t h a t were t o o  s m a l l t o be a d q u a t e l y sampled d u r i n g e a r l i e r months.  An  a d d i t i o n a l f a c t o r , p r o b a b l y o f o n l y minor importance, i s t h a t O c t o b e r emergence samples c o n t a i n e d many l a r v a l Orthocladinae was  i n d i c a t i n g that a p o r t i o n of the p o p u l a t i o n  p l a n k t o n i c f o r at l e a s t part of the time.  2.  Chironomidae (a)  Density  From September, 1963 u n t i l August 30, 1964 chironomids  2.0 mm. o r l o n g e r c o n s t i t u t e d 68.7% o f t h e  macroscopic benthic organisms.  S e a s o n a l changes i n t h e  d e n s i t i e s and p a t t e r n s o f emergence of t h e f o u r major groups of t h e Chironomidae a r e summarized i n F i g u r e 6.  The most  s t a b l e t a x a i n terms o f p o p u l a t i o n s i z e was t h e s u b f a m i l y  29  2000  i200  TANYPODINAE  1000 UJ  DU \-  l±J  5000  2 LU  < 3000  3 or  1000 UJ  < 5000  15001  CHIRONOMIN  co O c  u_ O  1300^  ffi 3 0 0 0  m 1100 m  1000  3000  i1500  TANYTARSINI  500  1000 O N 1963  D  J  F i g u r e 6 - S e a s o n a l changes i n l a r v a l d e n s i t i e s and a d u l t emergence of t h e Chironomidae; l a r v a e ; a d u l t s ~~ _ _ _  30 Tanypodinae. The Chironomini  subfamily Orthocladinae  and the  tribes  and T a n y t a r s i n i were a l l c h a r a c t e r i z e d  by  apparent w i n t e r maxima and summer minima. Data on t h e l a r v a l d e n s i t y and a d u l t emergence of f o u r of the l a r g e r more abundant s p e c i e s are p l o t t e d i n F i g u r e 7 t o i l l u s t r a t e m o r t a l i t y as w e l l as the s h i p t h a t l a r v a l d e n s i t y has  to emergence.  relation-  Tribelos  p r o t e x t u s , P o l y p e d i l i u m nubeculosum and P s e c t r o c l a d i u s sp. A are s h a l l o w water s p e c i e s r e s t r i c t e d almost e n t i r e l y to depths of l e s s t h a n 4.0  metres.  S e r g e n t i a sp. A i s a deep  water s p e c i e s r e s t r i c t e d f o r the most p a r t to depths of more t h a n 4.0  metres.  As i n d i c a t e d , T r i b e l o s p r o t e x t u s  and  P o l y p e d i l i u m nubeculosum have a much lower l a r v a l m o r t a l i t y than the o t h e r two  species.  For a v a r i e t y of r e a s o n s most of the  remaining  s p e c i e s were not s u i t a b l e f o r t h i s type of a n a l y s i s .  Larvae  of some s p e c i e s such as t h o s e of the genus P r o c l a d i u s were v e r y d i f f i c u l t t o s e p a r a t e w h i l e those of some of the s p e c i e s were too s m a l l to be a d e q u a t e l y sampled by gear.  other  the  S e v e r a l s p e c i e s began t o emerge b e f o r e the emergence  t r a p s were s e t o u t .  F i n a l l y many of the r a r e s p e c i e s were  not abundant enough t o be sampled The  adequately.  l a r v a l d e n s i t y i m m e d i a t e l y p r i o r to emergence  and the numbers of emerging a d u l t s f o r the more abundant  F i g u r e 7 - A comparison of l a r v a l d e n s i t y , a d u l t emergence and m o r t a l i t y o f f o u r s p e c i e s of Chironomidae.  32 species are presented  i n T a b l e V.  The s p e c i e s w i t h i n each  s u b f a m i l y o r t r i b e a r e l i s t e d i n o r d e r o f t h e i r approximate depth d i s t r i b u t i o n .  (b)  Distribution  Characteristic trated  i n F i g u r e 8.  types o f d i s t r i b u t i o n s  are i l l u s -  H a r n i s c h i a amachaerus i s a s h a l l o w  water s p e c i e s r e s t r i c t e d  t o depths o f l e s s than 2.0 metres.  A h i g h p r o p o r t i o n o f t h e s p e c i e s i n the l a k e i s r a r e o r absent below t h e f o u r metre depth c o n t o u r , but few o f them are r e s t r i c t e d  t o depths o f l e s s than 2.0 metres.  Charac-  t e r i s t i c a l l y they a r e about e q u a l l y abundant i n t h e 0-1.9 and 2^3.9 metre depth zones. P r o c l a d i u s d e n t i c u l a t u s i n common w i t h a l l t h e more abundant members o f t h e s u b f a m i l y Tanypodinae had a very uniform d i s t r i b u t i o n .  T h i s type o f d i s t r i b u t i o n  appears  to be a s s o c i a t e d w i t h t h e f r e e - l i v i n g and o f t e n p r e d a t o r y h a b i t s o f these l a r v a e .  One l a r g e r a r e s p e c i e s i n t h i s  s u b f a m i l y , P r o c l a d i u s s p . A, appears t o be r e s t r i c t e d deeper w a t e r but t h i s may be a s a m p l i n g from i t s low d e n s i t y .  artifact  t o the  resulting  Most o f t h e s p e c i e s i n t h e t r i b e  T a n y t a r s i n i ( s u b f a m i l y Chironominae) were u n i f o r m l y d i s t r i b u t e d , however, S t e m p e l l i n a b a u s e i and t o a l e s s e r Tanytarsus  extent  s p . B were more abundant i n s h a l l o w w a t e r .  P s e c t r o c l a d i u s s p . D o f t h e s u b f a m i l y O r t h o c l a d i n a e was a  T a b l e V.  D e n s i t i e s o f t h e more numerous s p e c i e s o f Chironomidae i n 1964; l a r v a e e s t i m a t e d from dredge samples t a k e n d u r i n g t h e 30 days i m m e d i a t e l y p r i o r t o commencement of a d u l t emergence; emerging a d u l t s e s t i m a t e d w i t h emergence t r a p s . DENSITY PER SQUARE METRE 0 - 1.9 metres Larvae Adults  S u b f a m i l y Tanypodinae Procladius denticulatus Psilotanypus bellus P r o c l a d i u s "freemani Ablabesmyia m o n i l T s Subfamily Orthocladinae • H e t e r o t r i s s o c l a d i u s sp. A * T r i s s o c l a d i u s sp. ~A Psectrocladius sp. A P s e c t r o c ladius" sp. D Heterotanytarsus sp. A **Parakiefferiella nigra P s e c t r o c l a d i u s sp. B S u b f a m i l y Chironominae Tribe Chironomini H a r n i s c h i a amachaerus Q P o l y p e d i l i u m (Tr) s i m u l a n s Polypedilium (Pent7~tritum Cryptochironomus s p . B P o l y p e d i l i u m (P) nubeculosum P a g a s t i e l l a sp. A Tribelos protextus Chironomus (L) modestus S e r g e n t i a sp. A s p r i n g emerging S e r g e n t i a sp. A f a l l emerging Chironomus (C) r e m p e l i i Tribe Tanytarsini **Stempellina bausei T a n y t a r s u s sp. B T a n y t a r s u s sp. C * * Z a v r e l i a sp. A  421 182 344 535 2820 2218 2839 287 22 — —  115 —  2208 48 468 1730 296 29  190 132 70 286 —  634 134 14 2 12 86 108 54 20 54 632 86 6  2.0 - 3.9 metres Larvae Adults 267 89 244 222 1533 1800 3600 556 67 —  333  _ _  1080 1510 —  -146 1694 894 118  * Emerged b e f o r e emergence t r a p s were s e t o u t **Larvae were t o o s m a l l t o be sampled a d e q u a t e l y ° L a r v a e were i n c l u d e d w i t h those o f P. t r i t u m  —  320 225 45 80 20  267 289 578 1422 311 67 578 133 89 —  2511  120 40 60 245 —  10 180 5 90 1475 __  1710 89 644 5932 2378 1378  15 280 50 115 830 230 350  45  10  356  145  22  20  2578 311  405 50  378 1267  10 545 270  —  —  —  140 95 35 465  4.0 - 6.0 metres Larvae Adults  —  __  933 3666 —  —  40 1645 1215 390  —  —  —  —  —  —  89 200 67 89  —  35 35 —  90  0-1-9  2-3-9  4-6  0-1-9  2-3-9  DEPTH IN M E T R E S Figure 8 - D i s t r i b u t i o n patterns of four species of Chironomidae i n M a r i o n Lake.  4-6  35 common s p e c i e s t h a t had t h i s type of d i s t r i b u t i o n . P s e c t r o c l a d i u s s p . B and S e r g e n t i a sp. A are s p e c i e s t h a t were much more abundant i n deeper w a t e r . type of d i s t r i b u t i o n was  two This  shared by Chironomus r e m p e l i i and  Chironomus d e c o r u s of the s u b f a m i l y Chironominae and P a r a k i e f f e r i e l l a n i g r a of the s u b f a m i l y  (c)  Orthocladinae.  Emergence Season  The p e r i o d s of a d u l t emergence are shown i n Figure 9.  The  apparent d u r a t i o n of each p e r i o d i s p a r t l y  i n f l u e n c e d by the sample s i z e but o t h e r more p e r t i n e n t r e l a t i o n s h i p s are apparent.  Generally speaking  the  O r t h o c l a d i n a e emerge i n s p r i n g and f a l l whereas the Chironominae and Tanypodinae emerge i n l a r g e numbers throughout the summer.  Depth C h a r a c t e r i s t i c emergence p a t t e r n s are  illustrated  i n F i g u r e 10.  P r o c l a d i u s f r e e m a n i , P s e c t r o c l a d i u s sp. A  and T a n y t a r s u s  sp. C are s p r i n g - e m e r g i n g  at approximately  s p e c i e s t h a t emerge  the same time a t a l l d e p t h s .  Emergence  o v e r the deeper water i s d e l a y e d by a p p r o x i m a t e l y  one  or  two weeks but t h i s d e l a y i s not n e a r l y as pronounced as i n  SAMPLE FEB SIZE  MARCH APRI L  MAY  JUNE  JULY  AUG  SEPT  OCT  Subfamily Tanypodinae Tanypus sp. A Procladius  sp. A  Zavrelimyia  sp.  Procladius  13  B  2  freeman!  Ablabesmyla  monllis  Zavrelimyia  sp. A  Zavrelimyia  sp.  Procladius  54 285 1  C  1  denticulatus  147  Thienemannimyia sp. A  1  P s i l o t a n y p u s , be H U B  93  C l i n o t a n y p u s sp. A Larsia  1  acrocincta  Psectrotanypus v a r i u s  Subfamily  Orthocladinae  T r i s s o c l a d i u s sp. A  15  H e t e r o t r i s s o c l a d i u s sp. A Paraklefferlella  nigra  P s e c t r o c l a d i u s sp. C Psectrocladius  sp.  19-9  35 76-8  D  112-36  H e t e r o t a n y t a r s u s sp. A P s e c t r o c l a d i u s sp. A  18 383  Protanypus sp. A  8  P s e c t r o c l a d i u s sp.  F  P s e c t r o c l a d i u s sp.  B  Paraklefferiella  4  305  coronata  39  Corynoneura sp. A  2  P s e c t r o c l a d i u s sp. Cricotopua  E  6  tricinctus  P s e c t r o c l a d i u s sp.  3  G  2  Subfamily Chironomldae T r i b e Chironoraini Chironomus decorus Sergentia  31-85  sp. A  10  Chironomus r e m p e l i i Microtendipes Harnischla  pedellus  alphaeus 489  P a g a s t i e l l a sp. A Tribelos  89  protextus  Chironomus modestus Cryptochironomus sp. A Cryptochironomus sp.  B  Polypedilium  nubeculosum  Polypedllium  siroulans  Harnischla  amacbaerus  HarniBchia  galaptera  Polypedllium Harnischla  tritum  2  83  potamogeti  Tribe Tanytarsini Lupdstroemia sp. A  Stempellina  4-20 839  Tanytarsus sp. C bausei  81  Tanytarsus excavatus Z a v r e l i a sp. A Lundstroemia sp Tanytarsus sp.  B B  3  1176  Tanytarsus sp. A  F i g u r e 9 - S e a s o n a l p e r i o d s o f a d u l t emergence o f the Chironomidae of M a r i o n Lake; v e r t i c a l l i n e s r e p r e s e n t the d a t e s a t w h i c h 1/2 the emergence had o c c u r r e d .  Tanytarsus sp C MAY  | JUNE | JULY  | AUG | SEPT | OCT  Zavreha sp A MAY | JUNE | JULY  | AUG | SEPT | OCT  Figure 10 - Emergence patterns of s i x species of Ghironomidae i n Marion Lake; black histograms = males; white histograms = females.  38  some o f t h e summer-emerging s p e c i e s . emergence o f T a n y t a r s u s  The l o n g p e r i o d o f  s p . C was u n u s u a l f o r a s p e c i e s  t h a t b e g i n s emergence i n t h e s p r i n g .  Males o f P s e c t r o c l a d i u s  s p . A emerged about a week e a r l i e r than t h e f e m a l e s .  This  phenomenon, p r e v i o u s l y r e p o r t e d by m i l l e r (1941), was common e s p e c i a l l y w i t h members o f t h e s u b f a m i l y  Orthocladinae.  A b l a b e s m y i a m o n i l i s emerges i n t h e summer and autumn and i n common w i t h o t h e r Tanypodinae t h e r e was l i t t l e d e l a y i n t h e time o f emergence over deeper w a t e r .  Many more  f e m a l e s o f t h i s s p e c i e s than males emerged over deeper water.  T h i s phenomenon was not noted w i t h any o f t h e o t h e r  species. P a g a s t i e l l a s p . A and Z a v r e l i a s p . A a r e summeremerging s p e c i e s t h a t show t h e c h a r a c t e r i s t i c  delayed  emergence over deeper w a t e r . I  A l l s p e c i e s t h a t were compared emerged e a r l i e r i n 1963 than 1964. T h i s i s almost c e r t a i n l y because o f t h e h i g h e r l a k e t e m p e r a t u r e s i n 1963. 3).  (Table I ; F i g u r e s 2 and  F u r t h e r e v i d e n c e o f t h e e f f e c t s of temperature on t h e  r a t e s o f development was p r o v i d e d by r e a r i n g  experiments.  L a r v a e r e a r e d a t t e m p e r a t u r e s 5°-7°C above those encountered i n t h e l a k e emerged as much as two weeks b e f o r e t h e n a t u r a l p o p u l a t i o n s even began t o emerge.  39  The  s p e c i f i c emergence p a t t e r n s when  considered  i n c o n j u n c t i o n w i t h the d a t a on l a r v a l growth i n d i c a t e t h a t the v a s t m a j o r i t y of s p e c i e s have one Marion Lake.  The  A which has a two  year l i f e c y c l e s i n  o n l y known e x c e p t i o n s  are P a g a s t i e l l a  sp.  y e a r l i f e c y c l e and H e t e r o t r i s s o c l a d i u s  s p . A, P s e c t r o c l a d i u s sp. C and P s e c t r o c l a d i u s sp. D which have two  generations  per y e a r .  S e r g e n t i a sp. A has  emergence p e r i o d s per y e a r which s u g g e s t s t h a t two a t i o n s are i n v o l v e d . stages  However, measurement of the  shows t h a t the p o p u l a t i o n s  are c o m p l e t e l y  I n d i v i d u a l s of the two p o p u l a t i o n s  two generlarval  separate.  appear t o be m o r p h o l o g i -  c a l l y i d e n t i c a l and f o r the p r e s e n t  are b e i n g c o n s i d e r e d  as  two v a r i e t i e s of the same s p e c i e s .  (d)  Vertical  Migrations  The movement of c h i r o n o m i d  l a r v a e o f f the bottom  i s a w i d e s p r e a d phenomenon i n M a r i o n Lake.  The  emergence  t r a p s used f o r c o l l e c t i n g p l a n k t o n i c l a r v a e were not d e s i g n e d to q u a n t i t a t i v e l y e s t i m a t e v e r t i c a l m i g r a t i o n s show t h a t t h i s phenomenon i s common and many s p e c i e s .  but  i n v o l v e s l a r v a e of  I n some s p e c i e s such as P o l y p e d i l i u m t r i t u m ,  Chironomus modestus and  S e r g e n t i a sp. A the v e r t i c a l m i g r a -  t i o n s i n v o l v e m o s t l y mature l a r v a e .  Conversely  only  immature l a r v a e of P o l y p e d i l i u m nubeculosum were c o l l e c t e d in  the emergence t r a p s .(Table V I ) .  40  Table VI.  The numbers of c h i r o n o m i d l a r v a e c o l l e c t e d i n emergence t r a p s . + = 0-9 l a r v a e ; ++ = 10 o r more l a r v a e "mature" (fourth instar) larvae  "immature" Total ! larvae  S u b f a m i l y Tanypodinae Ablabesmyia m o n i l i s Psilotanypus bellus P r o c l a d i u s spp. C l i n o t a n y p u s sp.  j j i J j  82 31 15 1  Subfamily Orthocladinae | T r i s s o c l a d i u s sp. A j P s e c t r o c l a d i u s sp. D i P s e c t r o c l a d i u s sp. A j H e t e r o t r i s s o c l a d i u s sp. AJ P a r a k i e f f e r i e l l a nigra i P s e c t r o c l a d i u s sp. G j Cricotopus t r i c i n c t u s J Corynoneura sp. A i  210 68 61 33 32 19 13 10  S u b f a m i l y Chironominae  i ! j j  ++ ++ ++ +  ++ + +  i  ++ ++ ++ ++ + + +  ++ + ++ ++ ++ ++ ++ ++  ! j i i  J " i  j  Tribe Chironomini Polypedilium tritum Chironomus modestus S e r g e n t i a sp. A P o l y p e d i l i u m nubeculosum Cryptochironomus sp. B Cryptochironomus sp. A Chironomus r e m p e l i i P a g a s t i e l l a sp. A  | j i ] J i | J i  22 19 13 11 7 3 3 i  Tribe Tanytarsini T a n y t a r s i n i spp. Stempellina bausei  j i ]  26 ! 2 !  ++ ++ ++  " i  ] i  ! ! ] !  + ++ + + + + ++  + +  i j  + +  A 24 hour p l a n k t o n s e r i e s taken August 20-21 i n d i c a t e d t h a t a pronounced d i e l m i g r a t i o n o f S e r g e n t i a s p . A o c c u r r e d a t s t a t i o n X (depth = 6.0 m e t r e s ) .  As i n d i c a t e d  i n F i g u r e 11 t h i s m i g r a t i o n was a t a maximum a t about 10 P.M.  (e)  Food  As i l l u s t r a t e d i n T a b l e s V i l a and V l l b s p e c i e s d i f f e r e d markedly i n t h e i r food h a b i t s . w i t h i n each o f t h e l a r g e r t a x a have been arranged  individual The s p e c i e s i n order  of s i z e t o i l l u s t r a t e what may be g e n e r a l r e l a t i o n s h i p s between s i z e and food h a b i t s . The phytoplankton.  s m a l l e r s p e c i e s tended t o f e e d p r i m a r i l y on Examples i n c l u d e L a r s i a a c r o c i n c t a ,  P a r a k i e f f e r i e l l a n i g r a and P a g a s t i e l l a s p . A, w h i c h a l l f e d almost e x c l u s i v e l y on l a r g e u n i c e l l u l a r d i a t o m s .  The o n l y  major t a x a t o which t h i s g e n e r a l i z a t i o n d i d not a p p l y was the T a n y t a r s i n i , where no marked d i f f e r e n c e s i n t h e f e e d i n g h a b i t s o f d i f f e r e n t s p e c i e s were The  apparent.  l a r g e r s p e c i e s i n t h e s u b f a m i l i e s Tanypodinae  and O r t h o c l a d i n a e f e d on o t h e r c h i r o n o m i d s smaller counterparts d i d .  more than  their  L a r v a o f t h e s u b f a m i l y Tanypod-  inae a r e u s u a l l y c o n s i d e r e d t o be predaceous but t h e d i g e s t i v e t r a c t s o f many o f t h e l a r v a e from Marion Lake were  surface 10 -  42  0J5m  10 •  0.5m  10h  1.5m  8pm  10 pm AUG 20  12 pm 4  2am  4am AUG 21  F i g u r e 11 - D i e l m i g r a t i o n of S e r g e n t i a sp.  A.  6 am  43  Subfamily Orthocladinae P a r a k i e f f e r i e l l a nigra H e t e r o t a n y t a r s u s sp. A P s e c t r o c l a d i u s sp. D P s e c t r o c l a d i u s sp. G T r i s s o c l a d i u s sp. A H e t e r o t r i s s o c l a d i u s sp. A P s e c t r o c l a d i u s sp. B P s e c t r o c l a d i u s sp. C P s e c t r o c l a d i u s sp. A •Cricotopus t r i c i n c t u s *Protanypus s p . A  4 3.0 7 3.4 7 5.1 12 5.3 5 5.6 9 5.7 6 5.8 6 6.0 5 6.9 2 7.5 5 12.0  + +++ +++ +++ +++ +++ +++ ++ +++ +++ ++  % phytoplankton  ++ +++ + +++ ++ + + ++ ++ +  ++  ++ +++  +++ + +++ +++ ++ ++ +++ ++ ++ +++ +++ + + +++  + +++ +++ + +++ ++ +++ ++ +++ + +++ ++ +++ ++ +++ +++ +++ + +++ +++  * one o f t h e l a r v a e examined c o n t a i n e d an a d u l t  % chironomids  +  % plant particles  % detritus  2 4.0 3 4.9 5 6.5 1 7.0 3 7.2 5 8.0 4 8.4 2 9.0 6 13.0  % crustaceans  S u b f a m i l y Tanypodinae Larsia acrocincta Psilotanypus bellus Ablabesmyia m o n i l i s P e n t a n e u r i n i sp. B P e n t a n e u r i n i sp. A Procladius denticulatus P r o c l a d i u s freemani P e n t a n e u r i n i sp. C P r o c l a d i u s sp. A  mean length of "mature" larvae  Gut c o n t e n t s o f f o u r t h i n s t a r c h i r o n o m i d l a r v a e c o l l e c t e d i n Marion Lake, B r i t i s h Columbia. +++ = more than 2 5 % o f volume; ++ = 5-25% o f volume; + = l e s s than 5% o f volume.  number examined  Table V i l a .  j 1  +++ +++  chironomid.  44  Table Vllb.  Gut c o n t e n t s o f f o u r t h i n s t a r c h i r o n o m i d l a r v a e c o l l e c t e d i n M a r i o n Lake, B r i t i s h Columb i a . +++ = more than 25% of volume; ++ = 525% of volume; + = l e s s t h a n 5% o f volume. co  CD  CD  fl •H B a  Xi -P  CD  c -  X  u  o S  fl  S u b f a m i l y Chironominae Tribe Chironomini P a g a s t i e l l a sp. A Harnischia~amachaerus Polypedilium tritum Polypedilium simulans Chironomus modestus H a r n i s c h i a potamogeti Cryptochironomus s p . B S e r g e n t i a s p . A' T*ribelos~protextus P o l y p e d i l i u m nubeculosum Cryptochironomus sp. A Microtendipes pedellus cEironomus decorus Chironomus r e m p e l f i Tribe Tanytarsini Z a v r e l i a sp. A StempelTina b a u s e i T a n y t a r s u s sp. B T a n y t a r s u s sp. C T a n y t a r s i n i sp. A Tanytarsus sp. A L u n d s t r o e m i a sp. A  Ci  r-l  0 <D  rH fl  r<  3  -P ai cu S  3.8 4.0 5.4 5.6 7.5 8.0 8.5 9.6 10.8 11.0 11.3 13.0 15.0 18.0  6 6 5 4 5 3 2  3.0 3.1 4.7 4.7 5.2 5.7 7.0  •rl -P 3  u a ft  U  -p fl  CD  rH  (0  •P •rH -P  •o  S=  5 5 4 4 5 2 5 2 5 3 3 4 4 4  fl +->  O  o u> ci  rH  ft  0  fl a  ft  y -cop  at rH 0  •p >> Xi  ft  s&  +++ +++ ++ +++ +++ +++ +++ ++ ++ +++ ++ +++ +++  +++ +++ +++ ++ +++ +++ + + + ++ ++ ++ ++ ++  +++ +++ +++ ++ +++ +++ + ++ +++ +++ ++ +++ ++ ++ +++  ++ ++ ++ ++ ++ ++ +++  ++ +++ ++ + +++ +++ +++ +++ +++ +++ +++ +++ + ++ +++  CO  fl  CD  a  3  o  w •rH  e ofl ou  •H Xi 0  45 often completely  (f)  f i l l e d with plant material,  Growth  Chironomids have f o u r l a r v a l i n s t a r s w i t h f o u r t h moult g i v i n g r i s e to the p u p a l s t a g e .  the  Heavily  s c l e r i t i z e d s t r u c t u r e s such as the head c a p s u l e  enlarge  o n l y a t the time of m o u l t i n g ; however, measurements of body l e n g t h i n d i c a t e t h a t the s o f t e r p a r t s of the  animal  undergo a s i g n i f i c a n t i n c r e a s e i n s i z e between m o u l t s . illustrated  As  i n F i g u r e 12 d i f f e r e n t s p e c i e s v a r i e d g r e a t l y  i n the r a t e of change i n t o t a l  length.  L a r v a e of P o l y p e d i l i u m nubeculosum grew v e r y r a p i d l y from August to November and v e r y l i t t l e d u r i n g  the  f o l l o w i n g n i n e months. A l l the common l a r g e r s p e c i e s i n the  subfamily  Chironominae w i t h the e x c e p t i o n of the f a l l - e m e r g i n g v a r i e t y of S e r g e n t i a this.  The  sp. A had  growth p a t t e r n s s i m i l a r to  l a r v a e of s m a l l e r Chironominae such as those  P o l y p e d i l i u m t r i t u m and P o l y p e d i l i u m s i m u l a n s d u r i n g the summer months immediately  of  grew r a p i d l y  p r i o r t o emergence.  S e r g e n t i a sp. A i s unique i n t h a t i t has both s p r i n g emerging and f a l l - e m e r g i n g p o p u l a t i o n s .  Both v a r i e t i e s  e x h i b i t more g r a d u a l growth t h a n P o l y p e d i l i u m nubeculosum however the growth p a t t e r n of the s p r i n g - e m e r g i n g  variety  Figure  12 - Growth p a t t e r n s of f i v e s p e c i e s of l a r v a e i n M a r i o n Lake.  chironomid  47 comparable i n a g e n e r a l way t o t h a t o f P. nubeculosum. P s e c t r o c l a d i u s s p . A, which had a one year 1  1  1  life  o  c y c l e and H e t e r o t r i s s o c l a d i u s s p . A, which had two genera t i o n s p e r y e a r both grew v e r y r a p i d l y d u r i n g w i n t e r .  The  summer g e n e r a t i o n o f H e t e r o t r i s s o c l a d i u s a l s o grew r a p i d l y but l a r v a e o f P s e c t r o c l a d i u s s p . A grew v e r y l i t t l e d u r i n g the summer.  A l l t h e common and abundant s p e c i e s o f t h e  s u b f a m i l y O r t h o c l a d i n a e grew c o n s i d e r a b l y d u r i n g w i n t e r and t h e phenomenon appears t o be g e n e r a l f o r t h e s u b f a m i l y . S p e c i e s o f O r t h o c l a d i n a e w i t h two g e n e r a t i o n s p e r year and those which emerged i n l a t e summer and f a l l grew r a p i d l y in  t h e summer as w e l l . P a g a s t i e l l a sp. A i s ' t h e o n l y chironomid  species  i n Marion Lake known t o have a two year l i f e c y c l e .  The  r a t e o f growth appears t o be r a t h e r u n i f o r m d u r i n g t h e e n t i r e l a r v a l s t a g e , b u t t h e younger l a r v a e were u n f o r t u n a t e l y t o o s m a l l t o be sampled a d e q u a t e l y fine-meshed s c r e e n  even w i t h t h e  ( a p e r t u r e s = 0.18 mm. s q u a r e ) .  The  s m a l l e s t specimen o f t h i s s p e c i e s was c o l l e c t e d September 2, 1964 i n s i d e a l a r v a o f A b l a b e s m y i a m o n i l i s .  Other  unusual f e a t u r e s of P a g a s t i e l l a sp. A are that i t feeds almost e x c l u s i v e l y on l a r g e u n i c e l l u l a r diatoms and i s , e x c e p t i n g f o r t h e v e r y young l a r v a e , a p p a r e n t l y benthic.  entirely  48 S i n c e l a r v a e of the Tanypodinae were as a group d i f f i c u l t t o i d e n t i f y w i t h o u t mounting  the specimens  on  s l i d e s the growth o f many of t h e s e s p e c i e s were not t h o r o u g h l y examined.  The s p e c i e s t h a t were examined i n  d e t a i l grew throughout the y e a r w i t h the r a t e o f growth b e i n g c o n s i d e r a b l y reduced d u r i n g w i n t e r .  3.  Trichoptera The two f a m i l i e s Psychomyiidae and  dominated  Phryganeidae  the c a d d i s f l y f a u n a o f Marion Lake.  Seasonal  changes i n the d e n s i t i e s of T r i c h o p t e r a l a r v a e a r e p r e s ented i n T a b l e IV.  As i n d i c a t e d t h i s t a x a r e p r e s e n t e d an  average of 0.3% o f the t o t a l numbers of m a c r o s c o p i c organisms.  bottom  G e n e r a l l y they were more abundant a t depths of  l e s s than 4 metres.  The f a m i l y Psychomyiidae was r e p r e s e n -  t e d by what appeared t o be a s i n g l e s p e c i e s which i n 1964 emerged d u r i n g t h e month of August.  A d u l t Phryganeidae  were c o l l e c t e d i n emergence t r a p s d u r i n g May, a g a i n i n September and O c t o b e r , 1964.  The  1964  and  largest  P s y c h o m y i i d a e and P h r y g a n e i d a e c o l l e c t e d d u r i n g the c o u r s e of t h i s s t u d y were 12 mm.  and 18 mm.  long r e s p e c t i v e l y .  The d i g e s t i v e t r a c t s o f the l a r v a e were not a n a l y z e d but P s y c h o m y i i d a e l a r v a e kept i n the l a b o r a t o r y a t  temper-  a t u r e s o f a p p r o x i m a t e l y 13°C were each f e d an 8-12 c h i r o n o m i d l a r v a e a p p r o x i m a t e l y once a week.  The  mm. larger  49 P h r y g a n e i d a e p r o b a b l y have an even g r e a t e r a p p e t i t e .  4.  Odonata N u m e r i c a l l y the Odonata formed o n l y about ( T a b l e IV) but  0.1%  of  the m a c r o s c o p i c bottom organisms  because  of  t h e i r l a r g e s i z e and predaceous f e e d i n g h a b i t s they  undoubtedly were much more i m p o r t a n t components of the bottom f a u n a t h a n t h e i r numbers i n d i c a t e d .  The keys of  P r i t c h a r d and Smith (1963) were used t o i d e n t i f y  this  group. The A n i s o p t e r a and Z y g o p t e r a were about e q u a l l y common w i t h b o t h s u b o r d e r s b e i n g more abundant i n s h a l l o w water.  P l a t h e m i s l y d i a D r u r y and L e u c o r r h i n i a  glacialis  Hagen, two s p e c i e s o f dragon f l i e s i n the f a m i l y L i b e l l u l i d a e , emerged i n May, June and J u l y .  A third  s p e c i e s , Aeshna i n t e r r u p t a Walker of t h e f a m i l y A e s h n i d a e , emerged from May u n t i l O c t o b e r .  The two s p e c i e s of  damsel  f l i e s , Enallagma b o r e a l ( S e l y s ) and Z o n i a g r o n s p . , emerged i n May,  June and J u l y . The d i g e s t i v e t r a c t s o f Odonata nymphs c o l l e c t e d  i n t h e f i e l d were not a n a l y z e d , but a l a r g e Aeshna i n t e r r u p t a nymph kept a t room temperature consumed as many as 15 l a r g e (8-12 mm.)  c h i r o n o m i d l a r v a e a t one f e e d i n g and  would almost c e r t a i n l y have e a t e n more had they been  50 available.  5.  Amphipoda (a)  D e n s i t y and D i s t r i b u t i o n  N u m e r i c a l l y t h e amphipods made up an average o f 11.4% o f t h e m a c r o s c o p i c bottom fauna w i t h t h e o n l y more abundant group b e i n g t h e c h i r o n o m i d l a r v a e .  Two s p e c i e s ,  H y a l e l l a a z t e c a (Saussure) and Crangonyx r i c h m o n d e n s i s o c c i d e n t a l i s Hubricht & H a r r i s o n occurred i n the lake with the former b e i n g about seven t i m e s t h e more abundant (Table I V ) .  Both s p e c i e s were more common i n s h a l l o w areas  and H y a l e l l a a z t e c a , i n p a r t i c u l a r , was almost absent from the deeper a r e a s .  (b)  Growth and Food  I n 1963 t h e e a r l i e r i n s t a r s o f Crangonyx r i c h m o n d e n s i s o c c i d e n t a l i s f i r s t appeared i n samples t a k e n i n May.  Growth was r a p i d u n t i l October and t h e n  e s s e n t i a l l y ceased u n t i l t h e f o l l o w i n g s p r i n g ( F i g . 1 3 ) . The young o f H y a l e l l a a z t e c a f i r s t appeared i n J u l y i n 1963 and grew r a p i d l y u n t i l O c t o b e r , when they had a p p r o x i m a t e l y reached t h e i r f u l l a d u l t s i z e ( F i g . 1 3 ) . I n 1964 the young o f both s p e c i e s f i r s t appeared about t h r e e weeks l a t e r than they had i n 1963. T h i s was almost c e r t a i n l y a  Hyalalla azteca  2 25  3 35 4 45 5 56 6 4 5 7 LENGTH (MM)  Crangonyx rlchmondansls occidentalis  75 8 9 5  1  2  3 4  5  6  7 8 9 10 11 12 LENGTH (MM.)  F i g u r e 13 - Monthly changes i n t h e l e n g t h f r e q u e n c i e s o f two s p e c i e s o f Amphipoda i n M a r i o n L a k e .  52 r e f l e c t i o n o f t h e lower t e m p e r a t u r e s encountered i n 1964. H y a l e l l a a z t e c a i s r e p o r t e d as b e i n g omnivorous (Cooper, 1964) and Crangonyx r i c h m o n d e n s i s may be p r i m a r i l y a scavenger,  occidentalis  as on s e v e r a l o c c a s i o n s  this  s p e c i e s was found f e e d i n g on f i s h t h a t had d i e d and sunk t o t h e bottom.  6.  Annelida S e a s o n a l changes i n t h e d e n s i t i e s o f t h e a n n e l i d s  are o u t l i n e d i n T a b l e I V . N u m e r i c a l l y t h e o l i g o c h a e t e s and  leeches represented  approximately  1 1 % o f t h e macro-  s c o p i c bottom f a u n a , w i t h o l i g o c h a e t e s b e i n g about 20 times the more abundant.  The most abundant f a m i l y o f t h e  O l i g o c h a e t a was t h e T u b i f i c i d a e . I t was r e p r e s e n t e d  by a t  l e a s t two s p e c i e s ; one a l a r g e abundant form t h a t was most common i n t h e 4-6 metre depth zone and t h e o t h e r a s m a l l e r more w i d e l y d i s t r i b u t e d but l e s s common form.  A very  mobile s p e c i e s b e l o n g i n g t o t h e f a m i l y L u m b r i c u l i d a e r e d commonly a t a l l d e p t h s .  occur-  The o t h e r o l i g o c h a e t e s con-  s i s t e d o f two o r more s m a l l s p e c i e s which were f o r t h e most p a r t r e s t r i c t e d t o t h e a r e a near t h e o u t l e t stream. There a r e no a p p r e c i a b l e d i f f e r e n c e s i n t h e seasonal width frequency d i s t r i b u t i o n s o f the T u b i f i c i d a e and p r o b a b l y r e p r o d u c t i o n o c c u r s over most of t h e y e a r . The  53 s m a l l e s t l u m b r i c u l i d s were c o l l e c t e d i n October and November i n d i c a t i n g t h a t r e p r o d u c t i o n was o c c u r r i n g a t t h i s time. The  most common l e e c h belonged t o t h e f a m i l y  Glossiphoniidae.  I t occurred  a t a l l depths but was most  abundant i n t h e 1-3 metre depth zone.  A d u l t s w i t h as many  as n i n e a t t a c h e d young were c o l l e c t e d i n June and J u l y , 1963  and a g a i n i n J u l y , 1964. A l a r g e r l e e c h o f t h e f a m i l y  H i r u d i d a e was c o l l e c t e d a t a l l depths but was r e l a t i v e l y rare.  I t s p e r i o d o f r e p r o d u c t i o n was n o t e s t a b l i s h e d .  7.  Mollusca The  molluscs  averaged 8.3% by numbers o f t h e  t o t a l m a c r o s c o p i c bottom fauna and were almost e q u a l l y common a t a l l seasons (Table I V ) .  The genus P i s i d i u m  ( c l a s s P e l e c y p o d a ) was a p p r o x i m a t e l y  13 times as abundant  as t h e genus H e l i s o m a ( c l a s s G a s t r o p o d a ) .  The l e n g t h f r e -  q u e n c i e s o f each o f these genera were s i m i l a r a t a l l times of t h e year and d i d not y i e l d i n f o r m a t i o n as t o t h e time of r e p r o d u c t i o n .  P i s i d i u m v a r i e d from 1-5 mm. l o n g and t h e  H e l i s o m a were 1.5-12 mm.  8.  Miscellaneous Miscellaneous  long.  Taxa t a x a made up an average o f 0.5% by  54 numbers o f t h e t o t a l m a c r o s c o p i c bottom fauna (Table I V ) . The Ceratopogonidae ( o r d e r D i p t e r a ) were t h e commonest organisms p l a c e d under t h i s d i v i s i o n . species of ceratopogonids occurred  At l e a s t t h r e e  i n the lake.  D a s y h e l e a sp. a t t a i n e d a maximum l e n g t h o f 8 mm. v e r y r a r e and no i n f o r m a t i o n r e g a r d i n g emergence i s a v a i l a b l e . Bezzia-Probezzia-Palpomyia 12 mm. r e s p e c t i v e l y .  The f i r s t I t was  i t s period of  The o t h e r two s p e c i e s b o t h o f t h e group a t t a i n e d l e n g t h s o f 18 and  The l a r g e r one emerged i n May and June  and t h e s m a l l e r one i n J u l y and August.  Both s p e c i e s were  widely d i s t r i b u t e d i n the lake. The remainder o f t h e m a c r o s c o p i c bottom fauna c o n s i s t e d o f a l d e r f l y l a r v a e , t a b a n i d l a r v a e and p l a n a r i a , a l l o f which were c o l l e c t e d v e r y i n f r e q u e n t l y .  UTILIZATION OF THE BOTTOM FAUNA BY RAINBOW TROUT 1.  D i u r n a l Feeding P a t t e r n A n a l y s i s o f t h e d i g e s t i v e t r a c t s o f rainbow t r o u t  (Salmo g a i r d n e r i i R i c h a r d s o n ) c o l l e c t e d August 10 and 11, 1963, showed t h a t t h e r e was a pronounced d i u r n a l p a t t e r n i n the f e e d i n g h a b i t s o f t h e f i s h . are summarized  i n Table V I I I .  These d i u r n a l d i f f e r e n c e s Whenever p o s s i b l e f o u r  were s e l e c t e d from each two hour p e r i o d .  fish  They were chosen  so t h a t t h e i r average f o r k l e n g t h was as near as p o s s i b l e  Table V I I I .  D i u r n a l d i f f e r e n c e s i n the average number o f f o o d organisms p e r t r o u t stomach on August 10 and 11, 1963; sunset - 8:35 P.M., s u n r i s e - 5:58 A.M. 3 PM-7 PM  7 PM-11PM  11PM-3 AM  3 AM-7 AM  7 AM-11AM  11AM-3 PM  Number o f stomachs  8  8  8  8  5  8  Range and mean f o r k l e n g t h s of sample f i s h i n cm.  16.3-23.5 (19.3)  11.5-23.3 (16.9)  12.9-23.5 (16.3)  11.2-19.3 (15.6)  16.1-21.4 (18.6)  11.9-19.7 (16.8)  Chironomidae pupae Chironomidae a d u l t s Mollusca Amphipoda Chironomidae l a r v a e Trichoptera larvae R o t i f e r s , C l a d o c e r a and Copepoda Odonata Hemiptera & C o l e o p t e r a T e r r e s t r i a l Insecta M i s c e l l a n e o u s immature Insecta Vertebrata Acarina  12.60  8.12 21.60 7.20  . 7.25 28.75 10.10 2.50 1.25 0.25  17.0 2.87 4.13 10.25 1.75  104.25 0.13 12.25 9.50 2.0 9.25  4.87 0.38 3.62 9.75 0.88 0.25  2.25 2.87  7.62 1.0 1.0  0.25 2.25  -  -  —  -  -  —  —  Total  147.00  22.25  2.25 1.75 5.0 1.80  -  6.25 0.25  1.0 0.75 2.0  0.13 1.75 1.75  3.75 1.87 1.0 0.37  0.25 0.50 0.13  0.13  0.25  0.13  -  28.03  47.31  56.44  -  -  -  -  -  -  25.82  -  -  tn tn  56 to  17 cm.,  the average v a l u e f o r the e n t i r e sample o f t r o u t  c o l l e c t e d o v e r the 24 hour p e r i o d . The stomachs c o n t a i n e d c o n s i d e r a b l y more j u s t a f t e r s u n s e t (8:35 P.M.)  organisms  and a f t e r s u n r i s e (5:58 A.M.),  i n d i c a t i n g t h a t most of the f e e d i n g was done i n the e v e n i n g and morning.  The c o n d i t i o n of the f o o d organisms  s e c t i o n o f the d i g e s t i v e t r a c t i s i l l u s t r a t e d  i n each  i n F i g u r e 14.  The food items i n the stomachs were l e s s d i g e s t e d i n samples c o l l e c t e d near sunset and s u n r i s e , a g a i n i n d i c a t i n g t h a t these were peak p e r i o d s of f e e d i n g a c t i v i t y . F i g u r e 15 shows number of a l l organisms  and  the  numbers o f c h i r o n o m i d a d u l t s and c h i r o n o m i d pupae i n the stomachs.  The e v e n i n g peak was  l a r g e l y due to c h i r o n o m i d  a d u l t s and the morning peak was due almost e x c l u s i v e l y t o c h i r o n o m i d pupae.  The o t h e r f o o d items were g e n e r a l l y con-  sumed a t a more u n i f o r m r a t e d u r i n g the 24 h o u r s .  2.  E s t i m a t e of the Food Consumption The r a t e of f l o w of f o o d through the d i g e s t i v e  t r a c t of the rainbow t r o u t was e s t i m a t e d by a n a l y z i n g the c o n t e n t s of the e n t i r e d i g e s t i v e t r a c t s of f i s h t a k e n o v e r a 24 hour p e r i o d b e g i n n i n g at 3 P.M., at 3 P.M.,  August 11, 1963.  August 10 and  ending  The method i s a p p l i c a b l e when  the f o l l o w i n g c r i t e r i a are a p p r o x i m a t e l y  satisfied.  F i g u r e 14 - D i u r n a l changes i n the c o n d i t i o n of f o o d organisms from d i f f e r e n t p a r t s of the d i g e s t i v e t r a c t of rainbow t r o u t ; samples of l e s s t h a n 10 food items not i n c l u d e d .  58  F i g u r e 15 - D i u r n a l changes i n the number of food organisms per stomach.  59 1.  The f i s h i s abundant and e a s i l y c o l l e c t e d at a l l times o f t h e day.  2.  The f i s h show d i u r n a l p a t t e r n s i n f e e d i n g b e h a v i o r . I d e a l l y p a r t i c u l a r "marker" organisms a r e consumed o n l y d u r i n g c e r t a i n p e r i o d s of the day.  3.  A l l t h e f o o d organisms i n the stomach can be and  4.  identified  counted.  The "marker" organisms can be i d e n t i f i e d and counted at a l l l o c a t i o n s i n the g u t .  5.  The f o o d organisms pass through the d i g e s t i v e t r a c t at the same r a t e . With r e g a r d t o the f i r s t c r i t e r i o n , a t l e a s t f o u r  f i s h were a v a i l a b l e f o r each 2 hour sample w i t h the except i o n of the 8 A.M.  sample when o n l y one f i s h was  caught.  The second p o i n t , as p r e v i o u s l y i n d i c a t e d , met a d m i r a b l y .  was  The t r o u t f e d p r i m a r i l y d u r i n g r e s t r i c t e d  time p e r i o d s and i n a d d i t i o n two of the major f o o d i t e m s , c h i r o n o m i d a d u l t s and c h i r o n o m i d pupae, were f o r the most p a r t each e a t e n a t o n l y one time o f the day. With r e g a r d t o the t h i r d p o i n t i t was found t h a t f o r p r a c t i c a l purposes the organisms i n the stomachs c o u l d a l l be i d e n t i f i e d and counted.  The o n l y i m p o r t a n t f o o d  60 items t h a t d i d o c c a s i o n a l l y break up w h i l e i n the stomach were the c h i r o n o m i d pupae. i d e n t i f i e d and counted tine.  U s u a l l y , however, they c o u l d be  i n the a n t e r i o r p a r t of the i n t e s -  When the r e s u l t s from a l l the sample are  averaged  the r a t i o of the number of a p a r t i c u l a r organism i n the i n t e s t i n e t o the number i n t h e stomach g i v e s an i n d i c a t i o n o f the r e l a t i v e r a t e s a t which the f o o d organisms f r a g m e n t i n g t o a p o i n t where they can no l o n g e r be  are counted.  The v a l u e o f t h i s r a t i o f o r s i x of the major food items are p r e s e n t e d i n T a b l e  IX. ,  As expected t h e organisms w i t h c o n s p i c u o u s u n d i g e s t i b l e p a r t s had the h i g h e r r a t i o s .  The head c a p s u l e s  of the c h i r o n o m i d and c a d d i s f l y l a r v a e and the s h e l l s of the m o l l u s c s c o u l d be r e a d i l y i d e n t i f i e d and counted r e g a r d l e s s o f the l o c a t i o n i n the d i g e s t i v e t r a c t from which had been t a k e n . 1.6  The r a t i o s f o r t h e s e t h r e e groups  and ranged from 1.70  f o r the m o l l u s c s .  found i n stomachs t h e r e were 1.6 1.6 = 2.6  organisms  F o r s o f t bodied  forms m u l t i p l y i n g the number of organ-  isms i n t h e stomachs by 2.6 number of organisms  1.48  i n the i n t e s t i n e and 1 +  i n the whole d i g e s t i v e t r a c t .  o r e a s i l y fragmented  averaged  f o r the c a d d i s f l y l a r v a e t o  Thus f o r e v e r y one of t h e s e  they  p r o v i d e s an e s t i m a t e of the  e a t e n d u r i n g the same p e r i o d as the  more d u r a b l e organisms  s t i l l p r e s e n t i n the i n t e s t i n e .  T a b l e I X . The r a t i o Number o f organisms i n t h e i n t e s t i n e s o f rainbow t r o u t Number o f organisms i n t h e stomachs o f rainbow t r o u t  j>  o r  important food items.  Caddis f l y larvae  Chironomid larvae  Molluscs  Chironomid adults  Amphipods  1.70  1.58  1.48  1.18  1.08  Chironomid pupae 0.41  s e v e r a  i  62 As suggested by T a b l e I X and T a b l e X c h i r o n o m i d pupae fragmented e a s i l y and f o r t h i s reason they were not as s a t i s f a c t o r y a "marker" adults.  organism as t h e c h i r o n o m i d  The t h o r a x e s o f t h e a d u l t s u s u a l l y remained  intact  and c o u l d be counted even i n t h e lower p a r t s o f t h e i n t e s t i n e thus s a t i s f y i n g p o i n t number 4. There i s some e v i d e n c e t o suggest t h a t t h e l a s t c r i t e r i o n , t h a t food organisms move through t h e gut a t t h e same r a t e , a p p l i e s t o t h e samples c o l l e c t e d i n M a r i o n Lake. The p y l o r i c v a l v e was c o n s i d e r e d as t h e o n l y l i k e l y p l a c e where t h e passage o f l a r g e r food organisms would be d e l a y e d . I f t h i s assumption i s c o r r e c t then a r e l a t i v e l y h i g h p e r centage o f t h e s e organisms would be expected t o o c c u r i n t h e h i n d p a r t o f t h e stomach. f o o d organisms  The d i s t r i b u t i o n s of v a r i o u s  i n t h e d i g e s t i v e t r a c t s o f t h e rainbow  are p r e s e n t e d i n T a b l e X.  trout  The organisms a r e arranged  a p p r o x i m a t e l y i n o r d e r o f t h e i r maximum d i a m e t e r but t h e r e i s no i n d i c a t i o n t h a t s i z e has a s i g n i f i c a n t e f f e c t on t h e r a t e o f f l o w o r organisms  through t h e p y l o r i c v a l v e .  Fur-  t h e r e v i d e n c e i n s u p p o r t o f t h i s was t h e s i m i l a r i t y o f t h e r a t i o organisms organisms  i n i n t e s t i n e s f o r the molluscs, chironomid i n stomachs  l a r v a e and c a d d i s f l y l a r v a e ( T a b l e I X ) .  The m o l l u s c s h e l l s  were much l a r g e r than t h e c h i r o n o m i d and c a d d i s f l y head c a p s u l e s y e t t h e s i m i l a r i t y o f t h e above r a t i o s s u g g e s t s  T a b l e X.  L o c a t i o n s o f t h e major food items i n the stomachs o f the sample f i s h . PERCENT stomach Total number  !  I  i  II  intestine i j..  Ill  IV  V  VI  Odonata nymphs  !  128  | 28.9  21.1 ,' 11.7  12.5  12.5  13.3  Molluscs  !  786  ! 23.2  17.2 i 10.7  15.5  16.9  16.5  Caddis f l y larvae  j  257  j 15.6  21.4 j 11.3  18.7  20.2  12.8  Amphipods  i  421  i  25.2  22.8 !  9.5  17.1  20.2  5.2  Chironomid a d u l t s  !  928  i  22.8  23.2 ! 11.4  9.5  18.0  15.1  C h i r o n o m i d pupae  J  895  j 51.6  19.1 j ! 6.1  6.3  10.1  6.8  Chironomid  !  336  ! 22.3  16.4 ! 12.5  26.2  14.9  7.7  j  159  j 29.6  16.4 ! 10.7  15.1  18.9  9.4  larvae  R o t i f e r s , cladocerans and copepods  1  i  64 t h a t they were moving through the p y l o r i c v a l v e at the same rate. D i u r n a l changes i n the average numbers of a d u l t c h i r o n o m i d s p r e s e n t i n the d i f f e r e n t s e c t i o n s of the d i g e s t i v e t r a c t s of the sample f i s h are i n d i c a t e d i n F i g u r e 16. The  t h r e e o b l i q u e l i n e s r e p r e s e n t the maximum, minimum and  average e s t i m a t e o f the r a t e of f l o w o f t h i s food i t e m .  The  e s t i m a t e d average time r e q u i r e d f o r the organisms t o pass through the gut was The  8 hours.  above i n f o r m a t i o n was  then used t o c a l c u l a t e  t h e average number of organisms consumed p e r f i s h p e r  day.  T h i s was done by m u l t i p l y i n g the average number of organisms p r e s e n t i n the stomach x 2.6  x 3 where 2.6 was  the r a t i o of  organisms i n the e n t i r e d i g e s t i v e t r a c t s t o those i n the stomachs and 3 was  the number o f times per day t h a t the  f o o d items were c l e a r e d from the d i g e s t i v e  tract.  The e s t i m a t e d r a t e of consumption of v a r i o u s food items p e r f i s h p e r day are p r e s e n t e d i n T a b l e X I .  The  con-  sumption of food organisms by the p o p u l a t i o n i s based on a p o p u l a t i o n s i z e of 2887 i n d i v i d u a l s and a l a k e a r e a o f 13 hectares.  There were e s t i m a t e d t o be 349 tagged f i s h i n the  l a k e at the time t h a t the n e t s were s e t .  E l e v e n of t h e s e  marked f i s h were i n c l u d e d i n the sample of 91 f i s h t i n g a p o p u l a t i o n of 9 1 + 1 11+1  indica-  x 349 = 2887 i n d i v i d u a l s  65 4PM  6PM  8PM — 8 35 SUNSET  10PM  12PM  2AM  _ S 5 8 SUNRISE 6AM  10 A M  2 PM FORE STOMACH I  HIND S T O M A C H  INTESTINE  II  III INTACT  INTESTINE IV  DISINTEGRATING  ^  EXOSKELETON  M M  INTESTINE V  INTESTINE VI  ONLY  F i g u r e 16 - D i u r n a l changes i n t h e average number, c o n d i t i o n and l o c a t i o n o f a d u l t c h i r o n o m i d s i n t h e d i g e s t i v e t r a c t of rainbow t r o u t ; t h r e e o b l i q u e l i n e s r e p r e s e n t t h e minimum, maximum and a v e r age e s t i m a t e d r a t e a t which f o o d was moving through t h e d i g e s t i v e t r a c t .  T a b l e X I . Food i n t a k e o f t h e rainbow t r o u t c o l l e c t e d August 10 and 11, 1963 compared to t h e bottom f a u n a . Mean l e n g t h o f t r o u t = 17.1 cm.; mean w e i g h t o f t r o u t = 66.5 gm. Number e a t e n p e r day p e r fish  Number e a t e n p e r day p e r s q u a r e metre by p o p u l a t i o n  Number p e r square metre (sample s i z e =18 d r e d g i n g s )  Percent < standin crop eat per day  109.70  2.44  74.00  1.64  Mollusca Helisoma Pisidium  54.98 45.80 9.18  1.22 1.02 0.20  867 47 820  0.14 2.17 0.02  Amphipoda H y a l e l l a azteca Crangonyx r i c h m o n d e n s i s occidentalis  35.00 18.35 16.65  0.78 0.41 0.37  1320 1137 183  0.06 0.03 0.20  Chironomidae l a r v a e P s e c t r o c l a d i u s spp. Sergentia sp. A Ablabesmyia m o n i l i s Others  22.34 8.31 6.58 4.68 2.77  0.50 0.18 0.15 0.11 0.06  882 82 153 89 558  0.06 0.22 0.10 0.12 0.01  Trichoptera  16.46  0.37  R o t i f e r s and Entomostraca  12.65  0.28  Odonata  11.09  0.25  Chironomidae pupae Chironomidae  adults  larvae  H e m i p t e r a and C o l e o p t e r a  5.37  0.12  T e r r e s t r i a l insects  2.77  0.06  O t h e r immature i n s e c t s  0.87  0.02  Vertebrata  0.69  0.02  Acarina  0.35  0.01  Annelida  0  0  •  5.0  2.5  22  525  7.40  10.00  0.09  0  67 B a i l e y (1951).  T h i s e s t i m a t e i s not c o m p l e t e l y adequate  because i t does not t a k e f i s h l e s s than 10 cm. i n t o account and i t i s a l s o based on t h e assumption t h a t t h e r e was no unknown m o r t a l i t y o f tagged f i s h d u r i n g t h e p r e v i o u s 3 months. the  These two e r r o r s w i l l p a r t l y o f f s e t one a n o t h e r as  f i r s t e r r o r l e a d s t o an u n d e r e s t i m a t e and t h e second t o  an o v e r e s t i m a t e . The e s t i m a t e d d e n s i t y o f t h e bottom organisms i s based on o n l y 18 d r e d g i n g s so t h e v a l u e s f o r the  r a r e r organisms a r e apt t o be s u b j e c t t o c o n s i d e r a b l e  error.  The average l e n g t h s and w e i g h t s o f t h e f o r m a l i n  p r e s e r v e d specimens on which t h e s e e s t i m a t e s a r e based were 17.1 cm. and 66.5 gm. r e s p e c t i v e l y . the  D u r i n g t h e time t h a t  f i s h were c o l l e c t e d t h e w a t e r temperatures i n t h e l a k e  v a r i e d from 24.0°C a t t h e s u r f a c e t o 14.6°C a t t h e bottom. However, t h e m a j o r i t y o f t h e f i s h were caught i n an a r e a of  t h e l a k e when t h e bottom temperature was no l o w e r than  17°C.  3.  A v a i l a b i l i t y o f t h e Bottom Fauna t o t h e Rainbow Trout The d e n s i t i e s o f t h e major bottom organisms and  the  r a t e s a t which they were b e i n g consumed by rainbow t r o u t  are  i n c l u d e d i n T a b l e X I . The i n e v i t a b l e c o n c l u s i o n i s  t h a t p r e d a t i o n by rainbow t r o u t was n o t , a t t h e time t h e c o l l e c t i o n s were made, an i m p o r t a n t cause o f m o r t a l i t y f o r most o f t h e t a x a .  A measure o f t h e degree o f u t i l i z a t i o n  68  of v a r i o u s food items i s g i v e n by the c a l c u l a t e d p e r c e n t consumed per day.  Only those organisms t h a t c o u l d  estimated w i t h dredgings  be  were i n c l u d e d i n the c a l c u l a t i o n s .  The organisms s u b j e c t e d t o the h e a v i e s t p r e d a t i o n were the Odonata nymphs, c a d d i s f l y l a r v a e and  the  gastropod  H e l i s o m a , t h r e e of the l a r g e r forms c o l l e c t e d i n the samples.  S i m i l a r l y , Crangonyx r i c h m o n d e n s i s o c c i d e n t a l i s , a  l a r g e s p e c i e s of amphipod was  s u b j e c t to a h e a v i e r  o f p r e d a t i o n than the s m a l l e r H y a l e l l a a z t e c a .  level  The  major-  i t y of the c h i r o n o m i d s consumed were r e l a t i v e l y l a r g e , often planktonic species.  The d a t a a l s o i n d i c a t e d t h a t  the p u p a l and a d u l t s t a g e s of the Chironomidae are s u b j e c t to much h e a v i e r p r e d a t i o n than the l a r v a e . F i g u r e 17 i l l u s t r a t e s the g r e a t  discrepancy  between the r e l a t i v e abundances of organisms i n the environoment and  i n the t r o u t stomachs.  1.5%  of the  bot-  tom organisms s u p p l i e d more than h a l f the organisms consumed by the t r o u t .  I n a d d i t i o n , as i n d i c a t e d above,  the most numerous f o o d items were a l s o the l a r g e s t organisms.  I t i s apparent t h a t i f these v a l u e s were con-  v e r t e d to weight o r c a l o r i e s they would have f u r t h e r emphasized the importance of a v e r y few  species.  69  Other  0  20  40  60  80  Annelida  100  PERCENT IN LAKE  F i g u r e 17 - A comparison o f the r e l a t i v e abundance of bottom organisms i n t h e stomachs o f rainbow t r o u t and i n the l a k e e x p r e s s e d as a cumulat i v e p e r c e n t a g e . Organisms a r r a n g e d i n o r d e r o f t h e i r r a t i o s of % i n stomachs '% i i f l a k e  70 DISCUSSION METHODOLOGY One  o f t h e major problems f a c i n g  an a q u a t i c  b i o l o g i s t i s the s e l e c t i o n o f the proper sampling  gear.  T h i s may seem e l e m e n t a r y b u t n e v e r t h e l e s s i t i s a l l t o o common f o r i n v e s t i g a t o r s without  t o use c o m p l e t e l y  inadequate gear  any c o n s i d e r a t i o n o f i t s l i m i t a t i o n s .  rationale  behind  t h i s i s g e n e r a l l y t h a t t h e r e s u l t s must  be comparable w i t h those o f e a r l i e r w o r k e r s . admirable  The  T h i s i s an  g o a l b u t i f f o r example a s c i e n t i s t e l e c t s t o  use a s t a n d a r d method he s h o u l d a t l e a s t have an a p p r e c i a t i o n o f t h e l i m i t a t i o n s o f t h e gear. Jonasson (1955) has c i t e d examples o f where t h e use o f a s t a n d a r d  sieving  screen  ( a p e r t u r e s = 0.6 mm.  square) f o r washing dredge samples has l e d t o some v e r y erroneous c o n c l u s i o n s . horizontal  migration  He found t h a t the h y p o t h e t i c a l o f young Chironomus  anthracinus  l a r v a e was i n Lake Esrom a t l e a s t , o n l y an a r t i f a c t i n g from t h e use o f t o o c o a r s e a s i e v i n g s c r e e n .  result-  Similarly  the mesh gauge ( a p e r t u r e = 0.56 mm. square) used i n t h i s investigation chironomid  d i d not e f f e c t i v e l y sample t h e s m a l l e r  l a r v a e (Table I I I ) and had t h e s i e v e ' s  effi-  c i e n c y not been taken i n t o account t h e r e s u l t s would c e r t a i n l y n o t have been i n d i c a t i v e o f t h e t r u e s i t u a t i o n .  71 Jonasson (1955) found t h a t a mesh s i z e o f 0.2 mm. was s u f f i c i e n t t o r e t a i n a l l l a r v a e o f C.  square  anthracinus,  however i n t h e Marion Lake study a mesh a p e r t u r e o f 0.18 mm. square was not adequate f o r the e a r l i e r i n s t a r s o f the s m a l l e r c h i r o n o m i d s .  I n any study o f t h e p o p u l a t i o n  dynamics o f a s p e c i e s i t i s almost e s s e n t i a l t o use a mesh s i z e t h a t w i l l p e r m i t an e s t i m a t e o f t h e e a r l i e r instars. The  time f a c t o r o f t e n n e c e s s i t a t e s the c h o i c e o f  a c o a r s e r mesh; however, i t i s advantageous t o have some measure o f t h e e r r o r i n v o l v e d .  The approach used i n t h i s  s t u d y was t o s i e v e a moderate number o f d r e d g i n g s through a f i n e r gauge s i e v e as w e l l and t h i s manner d e t e r m i n e c o r r e c t i o n f a c t o r s f o r l o s s through t h e c o a r s e r mesh. Two advantages o f u s i n g submerged f u n n e l  traps  f o r e s t i m a t i n g t h e p o p u l a t i o n s o f emerging i n s e c t s a r e the s i m p l i c i t y o f t h e method and t h e f a c t t h a t p u p a l e x u v i a e a r e a l s o c o l l e c t e d and can u s u a l l y be a s s o c i a t e d w i t h the a d u l t s .  As Mundie (1956) s u g g e s t s ,  one o f t h e  major problems w i t h emergence t r a p s i s t h a t o f e s t i m a t i n g t h e i r sampling e f f i c i e n c i e s .  No attempt was made t o  d e t e r m i n e t h e t r u e e f f i c i e n c i e s o f t h e t r a p s used i n t h i s s t u d y , but comparison o f l a r v a l p o p u l a t i o n s p r i o r t o emergence and t h e e s t i m a t e d  emerging p o p u l a t i o n o f a d u l t s  i n d i c a t e s t h a t the t r a p i s much more e f f i c i e n t f o r some  72 s p e c i e s than f o r o t h e r s . was  The average s a m p l i n g  efficiency  e s t i m a t e d t o be 36% but the t r u e e f f i c i e n c y was  almost  c e r t a i n l y h i g h e r than t h i s because no c o r r e c t i o n s were made f o r any l a r v a l and p u p a l m o r t a l i t y o c c u r r i n g i n the interval.  I n those areas where the type o f bottom p r e v e n t s  the e f f i c i e n t use o f dredges  then d a t a from emergence  t r a p s c o u l d be expected t o p r o v i d e a b e t t e r e s t i m a t e o f the s t a n d i n g c r o p of i n s e c t s . I n t h i s i n v e s t i g a t i o n a method based e n t i r e l y  on  f i e l d samples was used t o e s t i m a t e the food r a t i o n o f the rainbow t r o u t i n the l a k e .  Had  time p e r m i t t e d i t would  have been advantageous t o e v a l u a t e the a c c u r a c y o f t h i s method by comparing  the r e s u l t s o b t a i n e d w i t h those from  c o n t r o l l e d f e e d i n g e x p e r i m e n t s c a r r i e d out under l a b o r a t o r y conditions.  As i n d i c a t e d i n the t e x t of t h i s t h e s i s ,  any  e r r o r s i n h e r e n t i n the method appear t o have been of a minor n a t u r e i n the p a r t i c u l a r samples examined.  A major  d i s a d v a n t a g e of t h i s method i s t h a t i t can o n l y be a p p l i e d t o p o p u l a t i o n s t h a t are l a r g e , e a s i l y sampled and have a diurnal feeding pattern.  On the o t h e r hand a m o d i f i c a t i o n  of t h i s method has s u b s e q u e n t l y been used w i t h s u c c e s s by Gordon (1965) on a p o p u l a t i o n of t h e s u r f p e r c h a g g r e g a t a Gibbons, i n d i c a t i n g t h a t t h i s approach  Cymatogaster may  p o t e n t i a l l y be a p p l i c a b l e t o a wide v a r i e t y of p o p u l a t i o n s .  73  POPULATION DYNAMICS As i n d i c a t e d i n T a b l e IV and F i g u r e 6 the maximum  d e n s i t y of c h i r o n o m i d l a r v a e was  January-February p e r i o d .  r e c o r d e d i n the  These d e n s i t i e s have been c o r -  r e c t e d f o r the l o s s of l a r v a e o v e r 2 mm. uncorrected  estimates  ( a p e r t u r e s = 0.56  mm.  i n length.  based on the s t a n d a r d  sieving  The screen  square) i n d i c a t e d an even g r e a t e r  i n c r e a s e from the November-December p e r i o d . apparent w i n t e r maxima are c o n s i d e r e d h i s t o r i e s of the s p e c i e s  When these  i n l i g h t of the  life  i n v o l v e d they become, as Cooper  (1964) s u g g e s t s , t o t a l l y u n a c c e p t a b l e .  They are i n s t e a d a  r e s u l t of the i n a d e q u a c i e s of the s a m p l i n g gear. S e a s o n a l changes i n abundance are i n t i m a t e l y r e l a t e d to a d u l t emergence.- However, t h i s f a c t i s not r e a d i l y apparent when comparisons are made at the l e v e l (Fig. 6).  The  g e n e r a l d e c l i n e from the  "maxima" to the M a r c h - A p r i l  p e r i o d was  a l o n e , s i n c e o n l y the O r t h o c l a d i n a e  to p r e d a t i o n .  The  winter t o emergence  were emerging i n s i g -  n i f i c a n t numbers d u r i n g t h i s i n t e r v a l . were at l e a s t p a r t l y due  not due  family  These d e c l i n e s  t o and perhaps almost e n t i r e l y  r e s i d e n t p o p u l a t i o n of rainbow t r o u t  (Salmo g a i r d n e r i i ) f e d p r i m a r i l y on bottom fauna and A p r i l was  due  since  f o r them a p e r i o d of r a p i d growth i t i s apparent  t h a t they were f e e d i n g a c t i v e l y and hence p r o b a b l y c o n t r i b u t i n g s i g n i f i c a n t l y t o t h i s d e c l i n e i n numbers of bottom  74  organisms.  Other v e r t e b r a t e p r e d a t o r s i n c l u d e d the kokanee  salmon, Oncorhynchus n e r k a (Walbaum), the r o u g h - s k i n newt, T a r i c h a g r a n u l o s a ( S k i l t o n ) and the n o r t h w e s t e r n Ambystoma g r a c i l e g r a c i l e ( B a i r d ) . was  salamander,  Each o f t h e s e s p e c i e s  common i n the l a k e and t h e i r combined e f f e c t on the  bottom f a u n a was  likely  significant.  There i s a d i s t i n c t l i k e l i h o o d } however, t h a t most o f the p r e d a t i o n o c c u r r i n g i n the b e n t h i c community i s due t o o t h e r i n v e r t e b r a t e s .  Caddis l a r v a e and Odonata  nymphs kept i n the l a b o r a t o r y consumed a v e r y l a r g e number of  c h i r o n o m i d l a r v a e , and had t h e i r c o u n t e r p a r t s i n the  l a k e f e d at a s i m i l a r r a t e each c a d d i s l a r v a e would have consumed a p p r o x i m a t e l y one c h i r o n o m i d per week w h i l e each Odonata nymph would have r e q u i r e d a p p r o x i m a t e l y one omid l a r v a e per day. predaceous of  7.9%  I n a d d i t i o n the Tanypodinae,  the  s u b f a m i l y o f c h i r o n o m i d s , r e p r e s e n t e d an  of the t o t a l f a u n a .  chiron-  average  T h i s seems a v e r y h i g h p e r c e n -  tage f o r a s t r i c t l y predaceous  p o p u l a t i o n and i n f a c t  as  T a b l e s V i l a and V l l b i n d i c a t e many of t h e s e s p e c i e s were omnivorous i n Marion Lake.  I t i s t r u e t h a t some of the  f o o d items p r e s e n t i n s i d e a l a r v a may  only indicate that  t h e s e items were p a r t of the c o n t e n t s of a n o t h e r  animal  p r e v i o u s l y consumed; however, the f a c t t h a t s m a l l e r s p e c i e s and the immature l a r v a e of l a r g e r s p e c i e s r a r e l y c o n t a i n a n y t h i n g but p h y t o p l a n k t o n and p l a n t p a r t i c l e s suggests t h a t  75 they a r e e a t i n g t h e s e items d i r e c t l y .  Nevertheless  many  Tanypodinae l a r v a e d i d c o n t a i n o t h e r c h i r o n o m i d l a r v a e , p a r t i c u l a r l y those o f P a g a s t i e l l a s p . A, a s m a l l abundant c h i r o n o m i d not found i n any o f t h e 45 t r o u t stomachs examined. When comparisons o f t h e changes i n l a r v a l and  a d u l t emergence a r e made a t t h e s p e c i e s  density  l e v e l as i s  done i n F i g u r e 7 t h e r e l a t i o n s h i p between them i s much clearer.  There i s c o n s i d e r a b l e  evidence suggesting  that  the v e r y d i f f e r e n t m o r t a l i t y r a t e s o f t h e f o u r s p e c i e s a r e i n t i m a t e l y r e l a t e d t o the behavior of the larvae. protextus  Tribelos  and P o l y p e d i l i u m nubeculosum both had low l a r v a l  mortality rates.  Emergence samples and p l a n k t o n  samples  have shown t h a t f o u r t h i n s t a r l a r v a e o f these two s p e c i e s are r a r e l y i f e v e r p l a n k t o n i c  (Table V I ) .  I n comparison  l a r v a e o f P s e c t r o c l a d i u s s p . A and S e r g e n t i a s p . A, which both had h i g h e r  l a r v a l m o r t a l i t y r a t e s , were f r e q u e n t l y  c o l l e c t e d i n emergence samples and i n a d d i t i o n S e r g e n t i a s p . A was c o l l e c t e d i n l a r g e numbers i n a s e r i e s o f p l a n k t o n samples t a k e n d u r i n g t h e n i g h t o f August 20-21, 1963 ( F i g . 11).  T h i s movement o f f t h e bottom almost c e r t a i n l y a f f e c t s  the a v a i l a b i l i t y t o p r e d a t o r s rates.  and c o n s e q u e n t l y t h e m o r t a l i t y  I t was s u r p r i s i n g t o f i n d t h a t about 3 0 % o f a l l t h e  c h i r o n o m i d l a r v a e found i n t h e sample t r o u t stomachs were those o f S e r g e n t i a s p . A.  The times t h a t most o f t h e l a r v a e  76 were consumed  (Table V I I I ) and t h e time of the maximum  v e r t i c a l m i g r a t i o n o f S e r g e n t i a s p . A ( F i g . 11) a l s o c o i n cide. I n e v e r y case t h e m o r t a l i t y r a t e s a r e a p p a r e n t l y h i g h e r w h i l e the a n i m a l s a r e i n the p u p a l s t a g e . reasonable  This i s  f i r s t because the magnitude o f the changes t h a t  o c c u r i n t h e t r a n s f o r m a t i o n from l a r v a t o pupa must r e s u l t i n p h y s i o l o g i c a l s t r e s s e s t h a t would c o n t r i b u t e to n a t u r a l mortality.  Secondly t h e v e r t i c a l movement o f pupae makes  them more v u l n e r a b l e t o f i s h p r e d a t i o n as i s a t t e s t e d by the f a c t t h a t they made up a p p r o x i m a t e l y  1/2 of the food  i t e m s found i n the t r o u t stomachs c o l l e c t e d August 10 and 11, 1963 (Table  VIII).  There a l s o seems t o be a c o r r e l a t i o n between the h i g h l a r v a l m o r t a l i t y r a t e o f P s e c t r o c l a d i u s s p . A and the tendency o f t h i s genus t o be p l a n k t o n i c (Table V) and thereby  s u b j e c t to h e a v i e r f i s h p r e d a t i o n .  dence of t h i s i s t h e f a c t t h a t a p p r o x i m a t e l y chironomid  Further  evi-  37% o f t h e  l a r v a e found i n the stomachs o f t h e sample t r o u t  were o f t h i s genus. A l l t h e s p e c i e s were not examined i n as g r e a t d e t a i l as those r e f e r r e d t o above, but t h e a v a i l a b l e e v i dence does s t r o n g l y suggest t h a t l a r v a e t h a t were f r e q u e n t l y p l a n k t o n i c were s u b j e c t t o heavy p r e d a t i o n and c o n s e q u e n t l y  77 had  a h i g h e r m o r t a l i t y than l a r v a e t h a t were e n t i r e l y  An a d d i t i o n a l f a c t o r perhaps more apparent w i t h the benthic  i n v e r t e b r a t e s , was  organisms (Table  benthic  other  t h a t the t r o u t s e l e c t e d l a r g e r  XI).  Mundie (1959) found t h a t many s u p p o s e d l y invertebrates occurred i n g hours of d a r k n e s s .  benthic  at the s u r f a c e of Lac La Ronge d u r He c o n c l u d e s t h a t the  benthic  i n v e r t e b r a t e s are much l e s s s t a t i c i n t h e i r d i s t r i b u t i o n than i s g e n e r a l l y a c c e p t e d .  S i m i l a r l y Nose (1961) con-  c l u d e s from l a b o r a t o r y s t u d i e s t h a t the f i r s t t h r e e i n s t a r s of Chironomus plumosus swim a c t i v e l y w h i l e f o u r t h i n s t a r l a r v a e are s e d e n t a r y b e n t h i c The  d a t a f r o m M a r i o n Lake c e r t a i n l y s u p p o r t  v a r i e t y of s p e c i e s was  A wide  vertical  t h a t of S e r g e n t i a sp. A ( F i g . 11), where  b o t h immature and mature l a r v a e were i n v o l v e d .  0.5  the  c o l l e c t e d i n the emergence t r a p s  (Table V I ) ; however, the most s t r i k i n g example of  t i o n may  the  organisms.  v i e w t h a t b e n t h i c organisms o f t e n m i g r a t e upwards.  m i g r a t i o n was  larval  This migra-  have been to a v o i d the low l e v e l of oxygen (about  cc/1)  t h a t e x i s t e d near the bottom on t h i s d a t e .  There seems to be l e s s r e a s o n f o r v e r t i c a l m i g r a t i o n s s h a l l o w water s p e c i e s .  in  P o s s i b l y the a d a p t i v e s i g n i f i c a n c e  of t h i s type of b e h a v i o r i s t h a t i t s e r v e s as a d i s p e r s i o n mechanism.  78 Many of the b e n t h i c s p e c i e s  i n M a r i o n Lake had  v e r y r e s t r i c t e d d i s t r i b u t i o n s , which i s r a t h e r s u r p r i s i n g i n view of the m o r p h o l o g i c a l  c h a r a c t e r i s t i c s of the  lake.  M a r i o n Lake would not seem t o o f f e r a wide v a r i e t y of h a b i t a t s as i t i s o n l y s i x metres deep, has  a gently slop-  i n g b a s i n and r a t h e r homogenous bottom s e d i m e n t s .  The  f a c t o r s t h a t r e s t r i c t t h e s e d i s t r i b u t i o n s were not  investi-  g a t e d , but p r e v i o u s  s t u d i e s i n c l u d i n g t h a t of M i l l e r  s u g g e s t t h a t temperature and perhaps oxygen are limiting factors.  Cooper (1964) p r e s e n t s  (1941)  important  e v i d e n c e sug-  g e s t i n g t h a t the d i s t r i b u t i o n of the amphipod, H y a l e l l a a z t e c a , may  be r e s t r i c t e d by low t e m p e r a t u r e s .  t h a t the growth of H y a l e l l a a z t e c a was a t a temperature of 10°C was  He  found  e f f e c t i v e l y halted  so i t i s p o s s i b l e t h a t temperature  the f a c t o r t h a t r e s t r i c t e d them t o s h a l l o w water i n  Marion Lake.  The  lower l e v e l of oxygen i n the deeper p a r t s  of the l a k e i s a n o t h e r p o s s i b l e l i m i t i n g f a c t o r . Temperature does have a profound e f f e c t on emergence p a t t e r n s of a d u l t c h i r o n o m i d s .  The  the  d a t a from  M a r i o n Lake s t r o n g l y suggest t h a t the t e m p e r a t u r e s encount e r e d by the l a r v a e , p a r t i c u l a r l y when they are i n the f o u r t h i n s t a r s t a g e , are d i r e c t l y r e l a t e d t o the o f emergence.  periods  S p e c i e s t h a t emergedin the s p r i n g o r  when the l a k e was  n e a r l y i s o t h e r m a l g e n e r a l l y had  p e r i o d s of emergence.  Notable exceptions  fall,  short  t o t h i s were  two  79 deep w a t e r s p e c i e s , Chironomus d e c o r u s and t h e f a l l emerging v a r i e t y o f S e r g e n t i a s p . A.  Shallow w a t e r s p e c i e s  had s h o r t emergence p e r i o d s r e g a r d l e s s o f t h e season i n I  which emergence o c c u r r e d .  On t h e o t h e r hand summer-  emerging s p e c i e s w i t h wide d i s t r i b u t i o n s i n t h e l a k e u s u a l l y had l o n g p e r i o d s o f emergence. S p e c i e s t h a t emerged d u r i n g t h e summer when t h e l a k e was s t r a t i f i e d u s u a l l y emerged s e v e r a l weeks l a t e r o v e r t h e deeper p a r t s o f t h e l a k e .  M i l l e r (1941) and  Mundie (1957) have r e p o r t e d s i m i l a r f i n d i n g s .  I n Marion  Lake t h e o n l y e x c e p t i o n s t o t h i s g e n e r a l r u l e were some members o f t h e Tanypodinae i n c l u d i n g Ablabesmyia m o n i l i s ( F i g . 1 0 ) . M i l l e r (1941) has suggested  t h a t t h i s may be  a r e s u l t o f f r e e - l i v i n g l a r v a e moving t o d i f f e r e n t temperat u r e zones so t h a t each l a r v a i s s u b j e c t e d t o  1  approximately  the same amount o f h e a t . As i n d i c a t e d i n F i g u r e 10 s p r i n g - e m e r g i n g emerged a t n e a r l y t h e same time over a l l depths.  species  This i s  almost c e r t a i n l y a r e f l e c t i o n o f t h e i s o t h e r m a l c o n d i t i o n s present  i n the lake at that time. The  males o f s e v e r a l o f t h e s p e c i e s emerged  before the females.  I n t h e case o f P s e c t r o c l a d i u s s p . A  ( F i g . 10) t h i s time l a g was about one week, however t h e phenomenon was l e s s marked i n o t h e r s p e c i e s .  Many more  f e m a l e s o f A b l a b e s m y i a m o n i l i s than males emerged o v e r  80 the deeper w a t e r .  T h i s phenomenon which M i l l e r  (1941)  i n t e r p r e t s as due t o a h i g h e r n a t u r a l m o r t a l i t y o f the males, was not noted w i t h any o t h e r The  species.  food h a b i t s o f v a r i o u s c h i r o n o m i d  have r e c e n t l y been d e a l t w i t h by P r o v o s t and Darby (1962). ing  chironomid  and Branch (1959)  F o r a more complete o u t l i n e o f the f e e d -  methods o f c h i r o n o m i d  Walshe (1951).  larvae  l a r v a e the r e a d e r  i s referred to  A n a l y s i s of the d i g e s t i v e t r a c t s of  l a r v a e c o l l e c t e d i n Marion Lake i n d i c a t e d t h a t  t h e r e was a r e l a t i o n s h i p between the s i z e o f t h e l a r v a e and  t h e i r choice of food  (Tables V i l a and V l l b ) .  s p e c i e s and young i n d i v i d u a l s o f l a r g e r s p e c i e s a t e -a h i g h e r p r o p o r t i o n o f p h y t o p l a n k t o n species d i d .  Smaller generally  than t h e l a r g e r  S i m i l a r l y t h e l a r g e r s p e c i e s o f Tanypodinae  and O r t h o c l a d i n a e  were more predaceous w h i l e t h e l a r g e r  Chironominae a t e a h i g h e r p r o p o r t i o n o f d e t r i t u s . Most o f t h e c h i r o n o m i d s i n Marion Lake had one y e a r l i f e c y c l e s , however, s e v e r a l s p e c i e s had two genera t i o n s p e r y e a r and one s p e c i e s , P a g a s t i e l l a s p . A, had a two year l i f e c y c l e .  As M i l l e r (1941) p o i n t s o u t t h e l e n g t h  of t h e l i f e c y c l e depends on t h e temperature c o n d i t i o n s . Thus a s p e c i e s may have a two year l i f e c y c l e i n one a r e a and  y e t w i t h a warmer c l i m a t e the same s p e c i e s may have a  one  year l i f e c y c l e .  Jonasson (1961) g i v e s an example o f  where a s i n g l e s p e c i e s , Chironomus a n t h r a c i n u s , may have  81 e i t h e r a one o r two y e a r c y c l e i n the same l a k e . S p e c i e s r e p o r t e d to have two year l i f e c y c l e s have g e n e r a l l y been l a r g e organisms ( j 6 n a s s o n , 1961;  Rempel,  1936)} however, P a g a s t i e l l a sp. A i s a v e r y s m a l l s p e c i e s . It  i s a l s o v e r y abundant, has a low l a r v a l m o r t a l i t y r a t e  and f e e d s almost e x c l u s i v e l y on l a r g e u n i c e l l u l a r Its  diatoms.  v e r y s e l e c t i v e f e e d i n g on a s i n g l e food source may  r e l a t e d t o i t s slow growth and cycle.  i t s r e s u l t i n g two year  be life  Lack o f much i n t e r s p e c i f i c c o m p e t i t i o n f o r food  might a l s o e x p l a i n the g r e a t abundance of the s p e c i e s . The  growth p a t t e r n s of the d i f f e r e n t  v a r i e d c o n s i d e r a b l y ( F i g . 12). c y c l e s as expected lived species.  chironomids  Species w i t h short  g e n e r a l l y grew more r a p i d l y than  life longer  On the o t h e r hand the marked d i f f e r e n c e s  encountered i n the s e a s o n a l growth r a t e s o f d i f f e r e n t s p e c i e s were not e x p e c t e d .  A l l the s p e c i e s i n v e s t i g a t e d  grew r a p i d l y d u r i n g September and O c t o b e r .  Some ceased  growing a t t h i s time w h i l e o t h e r s , p a r t i c u l a r l y  the  O r t h o c l a d i n a e , grew r a p i d l y throughout the w i n t e r .  The  phenomenon of r a p i d growth d u r i n g months when w a t e r tempera t u r e s a r e near f r e e z i n g i s almost c e r t a i n l y a r e f l e c t i o n o f the a b i l i t y of a s p e c i e s t o w i t h s t a n d c o l d c l i m a t e s . It  i s t h e r e f o r e not s u r p r i s i n g t h a t the most abundant  s u b f a m i l y i n a r c t i c l a k e s i s g e n e r a l l y the  Orthocladinae.  82 Many s p e c i e s grew a c t i v e l y d u r i n g t h e s p r i n g and summer w h i l e o t h e r s e x h i b i t e d v e r y l i t t l e growth d u r i n g t h e warmer p a r t s o f t h e y e a r .  UTILIZATION OF THE BOTTOM FAUNA Several investigators including B a l l Gerking  (1962) and H a m i l t o n  (1949),  (1961) have found l a r g e d i s -  c r e p a n c i e s between t h e p r o p o r t i o n s o f a n i m a l s environment and t h e p r o p o r t i o n s eaten by f i s h .  i n the There a r e  i n d i c a t i o n s t h a t f i s h s e l e c t food organisms o f a p a r t i c u lar size.  Cooper (1964) and H a m i l t o n  that yellow perch  (1961) both found  ( P e r c a f l a v e s c e n s ) consumed a h i g h p r o -  p o r t i o n o f t h e mature H y a l e l l a a z t e c a w h i l e h a r d l y z i n g the e a r l i e r i n s t a r s at a l l . s e l e c t l a r g e r food o r g a n i s m s . (Lepomis m a c r o c h i r u s )  Larger f i s h generally  F o r example, as b l u e  increase i n s i z e t h e i r diet  from p l a n k t o n t o bottom fauna  utili-  gills  shifts  ( G e r k i n g , 1962).  Some organisms such as o l i g o c h a e t e s and l e e c h e s are almost never found i n f i s h stomachs ( B a l l , 1949; G e r k i n g , 1962).  T h i s may be p a r t l y due t o t h e f a c t t h a t  s o f t bodied organisms a r e d i g e s t e d more q u i c k l y (Hess and Rainwater,  1939) and hence do not o f t e n appear i n stomach  contents.  On the o t h e r hand an a n i m a l t h a t remains b u r i e d  i n t h e bottom sediments,  as i s a p p a r e n t l y t h e case w i t h  83 the o l i g o c h a e t e s ,  i s l i k e l y t o be r a t h e r u n a v a i l a b l e t o  fish. Organisms p r e s e n t i n t h e stomachs o f rainbow t r o u t c o l l e c t e d i n M a r i o n L a k e , August 10 and 11, 1963, ©nsisted almost e n t i r e l y o f l a r g e b e n t h i c p l u s c h i r o n o m i d pupae and a d u l t s .  invertebrates  As i n d i c a t e d i n T a b l e  XI l a r g e Odonata and T r i c h o p t e r a were consumed a t a much g r e a t e r r a t e than t h e i r numbers i n t h e environment would indicate.  The l a r g e r m o l l u s c , H e l i s o m a , was s e l e c t e d o v e r  the s m a l l e r P i s i d i u m and s i m i l a r l y t h e l a r g e amphipod, Crangonyx r i c h m o n d e n s i s o c c i d e n t a l i s , was s e l e c t e d o v e r the s m a l l e r H y a l e l l a a z t e c a . As i n d i c a t e d e a r l i e r most o f t h e c h i r o n o m i d l a r v a e s e l e c t e d were s p e c i e s tonic. esting.  t h a t were f r e q u e n t l y  plank-  The case o f S e r g e n t i a s p . A i s p a r t i c u l a r l y  inter-  The members o f t h i s genus a r e l a r g e , abundant and  samples t a k e n August 10 and 11, 1963, i n d i c a t e t h a t t h e l a r v a e undergo a v e r y d e f i n i t e d i e l m i g r a t i o n I n a d d i t i o n t h e y were an i m p o r t a n t food  ( F i g . 11).  item i n the d i e t  of t h e rainbow t r o u t (Table X I ) , which, may e x p l a i n t h e i r h i g h l a r v a l m o r t a l i t y r a t e ( F i g . 7 ) . I have examined t h e stomach c o n t e n t s o f s e v e r a l sockeye salmon s m o l t s (Oncorhynchus nerka) c o l l e c t e d i n Maurice L a k e , a l a r g e l a k e i n c e n t r a l B r i t i s h Columbia by Mr. Lawrence M. D i l l .  84 These stomachs were c o m p l e t e l y f i l l e d w i t h l a r v a e o f Sergentia.  I n view o f t h e m i g r a t o r y b e h a v i o r o f S e r g e n t i a  sp. A i n Marion Lake and t h e f a c t t h a t sockeye salmon a r e n o r m a l l y p l a n k t o n f e e d e r s i t seems r e a s o n a b l e t o conclude t h a t t h e l a r v a e were p l a n k t o n i c when c a p t u r e d . I f the e v i d e n c e from the two l a k e s r e f e r r e d t o above i s a t a l l t y p i c a l o f o t h e r l a k e s i n t h e a r e a then t h i s one genus, S e r g e n t i a , i s e x t r e m e l y i m p o r t a n t as a food f o r f i s h . From an a p p l i e d s t a n d p o i n t , knowledge o f t h i s n a t u r e c o u l d be v e r y u s e f u l b e f o r e p o p u l a t i o n s a r e a l t e r e d by a r t i f i c i a l means.  At present benthic populations are  o f t e n u n w i t t i n g l y m a n i p u l a t e d when l a k e s a r e t r e a t e d w i t h f i s h t o x i c a n t s such as toxaphene and r o t e n o n e .  Cushing  and O l i v e (1956) o u t l i n e d the e f f e c t s o f t h e s e two p o i s o n s , and one i n t e r e s t i n g a s p e c t o f t h e i r i n v e s t i g a t i o n i s t h a t some o f the c h i r o n o m i d s s u r v i v e d .  I t i s l i k e l y t h a t those  t h a t d i d s u r v i v e were i n t h e a d u l t o r perhaps t h e egg s t a g e a t t h e time t h e t o x i c a n t was a p p l i e d .  If this i s  indeed t h e case then t h e t i m i n g o f t h e a p p l i c a t i o n o f the p o i s o n c o u l d be a d j u s t e d t o f a v o u r s p e c i e s t h a t a r e import a n t food organisms.  T h i s i s one a s p e c t o f f i s h e r i e s  management t h a t might w a r r a n t more d e t a i l e d  examination.  85 CONCLUSION  are  I t has l o n g been r e c o g n i z e d t h a t organisms  which  s i m i l a r morphologically are often very d i f f e r e n t  ecol-  o g i c a l l y y e t f o r t h e sake o f s i m p l i c i t y many s p e c i e s a r e f r e q u e n t l y grouped  i n a manner which b e a r s l i t t l e  to t h e a c t u a l r o l e p l a y e d i n t h e community.  relation  The  Chironomidae a r e an example o f one such group t h a t has o f t e n been t r e a t e d i n such a manner.  T h i s s t u d y has shown  t h a t t h e M a r i o n Lake c h i r o n o m i d s a r e i n f a c t v e r y d i f f e r e n t ecologically.  The s p e c i e s grew a t d i f f e r e n t t i m e s o f t h e  y e a r , f e d on d i f f e r e n t f o o d s and had v e r y d i f f e r e n t rates.  There were i n f a c t marked d i f f e r e n c e s i n a l l t h e  a s p e c t s o f t h e i r l i f e h i s t o r i e s t h a t were examined. are  mortality  These  a l l i m p o r t a n t f e a t u r e s o f t h e b e n t h i c community which  are o b s c u r e d o r l o s t i f t h e s p e c i e s a r e not c o n s i d e r e d individually. The s t a n d i n g c r o p o f bottom fauna i s o f t e n c o n s i d e r e d as one o f t h e more i m p o r t a n t i n d i c a t o r s o f t h e p o t e n t i a l o f a l a k e as a f i s h p r o d u c e r . limited value.  I t i s , however o f  Some organisms a r e r a r e l y o r never e a t e n  by f i s h , so from t h e s t a n d p o i n t o f f i s h e r i e s management t h e r e i s l i t t l e r e a s o n t o i n c l u d e them i n the c a l c u l a t i o n s . The v e r y g r e a t d i f f e r e n c e s i n t h e r e l a t i v e r a t e s a t w h i c h c l o s e l y r e l a t e d organisms were u t i l i z e d suggest t h a t a more  '  86  r e a l i s t i c measure of the l a k e s p o t e n t i a l c o u l d be had  by  c o n c e n t r a t i n g on o n l y the few s p e c i e s o r genera t h a t form the b u l k of the food of the f i s h .  Limnological  investi-  g a t i o n s which i n v o l v e an e v a l u a t i o n of the e c o l o g i c a l r o l e p l a y e d by i n d i v i d u a l s p e c i e s are l i k e l y to p r o v i d e more f r u i t f u l i n f o r m a t i o n t h a n s t u d i e s which i g n o r e the  dif-  f e r e n c e s between s p e c i e s . T h i s s t u d y has shown some of the advantages of w o r k i n g at the s p e c i e s l e v e l .  A l t h o u g h s t u d i e s at t h i s  l e v e l are t e d i o u s and o f t e n n e c e s s i t a t e a time consuming taxonomic s t u d y , the a d d i t i o n a l i n f o r m a t i o n i s l i k e l y j u s t i f y the e x t r a e f f o r t .  The  to  r e s u l t s of e c o l o g i c a l  i n v e s t i g a t i o n s t h a t are not c a r r i e d out at the  species  l e v e l i g n o r e , o r at best o v e r s i m p l i f y , r e l a t i o n s h i p s t h a t exist.  Indeed, a comprehensive u n d e r s t a n d i n g  of, for  example, energy t r a n s f e r w i t h i n a community, i s i m p o s s i b l e without  a d e t a i l e d knowledge of the l i f e h i s t o r i e s of  species  involved.  the  87 LITERATURE CITED A l l e n , K.R. 1951. The Horokwi s t r e a m , a s t u d y of a t r o u t p o p u l a t i o n . F i s h B u l l . N.Z., 10:1-231. B a i l e y , N.J.J. 1951. On e s t i m a t i n g the s i z e of mobile p o p u l a t i o n s from r e c a p t u r e d a t a . B i o m e t r i k a , 38:293306. B a l l , R.C. 1948. R e l a t i o n s h i p between a v a i l a b l e f i s h f o o d , f e e d i n g h a b i t s o f f i s h and t o t a l f i s h p r o d u c t i o n i n a M i c h i g a n L a k e . B u l l . M i c h , a g r i c . C o l l . Exp. Stn., 206:2-59. B o r u t z s k y , E.V. 1939. Dynamics of biomass of Chironomus plumosus i n the p r o f u n d a l of Lake B e l o i e . A r b e i t e n L i m n o l o g i s c h e n S t a t i o n K o s s i n o , 22:156-195 (Russian w i t h E n g l i s h summary). B r u n d i n , L. 1949. Chironomiden und andere b o d e n t i e r e d e r sudschwedischen u r g e b i r g s s e e n . Rep. I n s t . Freshw. Res. D r o t t n i n g h o l m , 30:1-880. Cooper, E.C. 1964. P o p u l a t i o n dynamics p r o d u c t i o n and r e g u l a t i o n o f a n a t u r a l p o p u l a t i o n of a f r e s h - w a t e r amphipod, H y a l e l l a a z t e c a . PhD. T h e s i s , Univ. of M i c h i g a n (L.C. Card No. Mic 64-12, 582) 93 p. U n i v . M i c r o f i l m s . Ann A r b o r , M i c h i g a n . C u s h i n g , C.E., and J.R. O l i v e . 1957. E f f e c t s of toxaphene and rotenone upon the macroscopic bottom fauna of two n o r t h e r n C o l o r a d o r e s e r v o i r s . T r a n s . Am. F i s h . S o c , 86:294-301. Darby, R.E. 1962. Midges a s s o c i a t e d w i t h C a l i f o r n i a r i c e f i e l d s , w i t h s p e c i a l reference to t h e i r ecology ( D i p t e r a Chironomidae). H i l g a r d i a , 32(1):1-206. G e r k i n g , S.D. 1954. The food t u r n o v e r of a p o p u l a t i o n . E c o l o g y , 35(1):490-498.  bluegill  . 1962. P r o d u c t i o n and f o o d u t i l i z a t i o n i n a p o p u l a t i o n of b l u e g i l l s u n f i s h . E c o l . Monogr., 3 2 ( 1 ) : 31-78. Gordon, C.D. MS. 1965. A s p e c t s of t h e l i f e h i s t o r y of Cymatogaster a g g r e g a t a Gibbons. M.Sc. T h e s i s , Dept. Z o o l o g y , U n i v e r s i t y o f B.C., Vancouver, 90 pp.  88 H a m i l t o n , A.L. MS. 1961. The macroscopic bottom fauna of Kenosee Lake. M.A. T h e s i s , Dept. B i o l o g y , U n i v e r s i t y of Saskatchewan, Saskatoon, 69 pp. Hayne, D.W., and R.C. B a l l . 1956. Benthic p r o d u c t i v i t y as i n f l u e n c e d by f i s h p r e d a t i o n . L i m n o l . Oceanogr., 1(3):162-175. Hess, A.D., and J.H. R a i n w a t e r . 1939. A method f o r measuring the f o o d p r e f e r e n c e o f t r o u t . C o p e i a , 154-157.  3:  j 6 n a s s o n , P.M. 1954. An improved f u n n e l t r a p f o r capt u r i n g emerging i n s e c t s , w i t h some p r e l i m i n a r y r e s u l t s . O i k o s , 5(2):179-188. . 1955. The e f f i c i e n c y of s i e v i n g t e c h n i q u e s f o r s a m p l i n g f r e s h w a t e r bottom f a u n a . O i k o s , 6 ( 2 ) : 183-207. . 1961. P o p u l a t i o n dynamics i n Chironomus a n t h r a c i n u s Z e t t . i n t h e p r o f u n d a l o f Lake Esrom. V e r h . i n t . V e r e i n . t h e o r . angew. L i m n o l . , 14:196-203. Lundbeck, J . 1926. Die bodentierwelt nordeutscher A r c h . H y d r o b i o l . , 7:1-473.  seen.  M i l l e r , R.B. 1941. A c o n t r i b u t i o n t o the e c o l o g y of the Chironomidae of C o s t e l l o Lake, A l g o n q u i n P a r k , O n t a r i o . P u b i s Ont. F i s h . Res. Lab., 49:7-63. Mundie, J.H. 1956. Emergence t r a p s f o r a q u a t i c i n s e c t s . M i t t . i n t . V e r e i n . t h e o r . angew. L i m n o l . , 7:1-13. . 1957. The e c o l o g y o f Chironomidae i n s t o r a g e r e s e r v o i r s . T r a n s . R. e n t . Soc. Lond., 109(5):149-232. . 1959. The d i u r n a l a c t i v i t y of the l a r g e r i n v e r t e b r a t e s a t the s u r f a c e o f Lac La Ronge, S a s k a t chewan. Can. J . Z o o l . , 37(6):945-956. Nose, T. 1961. On the emerging b e h a v i o r Chironomus plumosus l a r v a e . B u l l . Freshw. F i s h . Res. Lab. Tokyo., 11(2);: 11-18. P r l t c h a r d , A.E., and R.F. Smith. 1963. Odonata. pp. 106153 in R.L. U s i n g e r (ed.) A q u a t i c i n s e c t s of C a l i f o r n i a . U n i v . of C a l i f o r n i a P r e s s , B e r k e l e y .  89  P r o v o s t , M.W. , and N. Branch. 1959. Food o f c h i r o n o m i d l a r v a e i n P o l k County l a k e s . F l a . Ent., 42 (2): 49-62. Rawson, D.S. 1930. The bottom fauna o f Lake Simcoe and i t s r o l e i n t h e e c o l o g y o f t h e l a k e . P u b i s Ont. F i s h . Res. L a b . , 40:1-183.  Rempel, J.G. 1936. The l i f e h i s t o r y and morphology o f Chironomus h y p e r b o r e u s . J . B i o l . Bd. Can*, 2(2):209-  TZT.  R i c k e r , W.E. 1937. The food and t h e f o o d s u p p l y o f sockeye salmon (Oncorhynchus nerka Walbaum) i n C u l t u s Lake, B r i t i s h Columbia. J . B i o l . Bd. Can., 3(5):450468.  ~  . 1946. P r o d u c t i o n and u t i l i z a t i o n o f f i s h p o p u l a t i o n s . E c o l . Monogr., JL6(4) :373-391. S u b l e t t e , J.E., and J.S. Dendy, 1958. P l a s t i c m a t e r i a l f o r s i m p l i f i e d t e n t and f u n n e l t r a p s . SWest. N a t . , 3:220-223.  Walshe, B.M. 1951. The f e e d i n g h a b i t s o f c e r t a i n chironomid l a r v a e (subfamily Tendipedinae). Proc. z o o l . Soc. Lond., 121:63-79.  APPENDIX I ADULT EMERGENCE AND LARVAL DENSITIES OF THE CHIRONOMIDAE  T a b l e I . A d u l t emergence o f t h e Chironomidae i n numbers c o l l e c t e d p e r week. (Traps sampled an a r e a o f 0.9 m^) 1964 Number o f samples S u b f a m i l y Tanypodinae Procladius sp.A P r o c l a d i u s freemani Ablabesmyia~monilis Procladius denticulatus Thienemannimyia s p . A Psilotanypus bellus Clinotanypus sp. A Larsia acrocincta Psectrotanypus varius Subfamily Orthocladinae H e t e r o t r i s s o c l a d i u s sp. A P a r a k i e f f e r i e l l a nigra Psectrocladius sp. C Psectrocladius sp. D Heterotanytarsus sp. A Psectrocladius sp. A Psectrocladius sp. F Psectrocladius sp. B P a r a k i e f f e r i e l l a coronata Corynoneura s p . A Cricotopus t r i c i n c t u s Psectrocladius sp. G S u b f a m i l y Chironominae Tribe Chironomini Sergentia sp. A Chironomus r e m p e l i i Microtendipes pedellus H a r n i s c h i a alphaeus  6 13  MAY 20  18 27  27  18 27 27  3 6 — —  2 10  11 16  27  JUNE 3 10 17 24  4 2  10 4 1 3 — 11 13 9 2 37 25 9 3 2 5 3 18 15 33 17 2 — 8 3 3 1 — 1 197 150 34 1  7 21 1 —  4 4 3  4 2 8 3 -- — 1 — 2  JULY 8 15 22 29  18 18 18 18 18 18  7 7  AUGUST 5 12 19 26  9 18 18  3 9 20 61 41 17 20 18 14 1 4 11 24 10 10 21 37 ._ i __ __ 2 5 11 11 12 1  9 18  9 12  2  SEPTEMBER 9 16 23 30  9 13 10  6  6  8  8 10 22 19 8 3 3 2  8  4  3 1  1  l  1 --  1 -- 1 11 9 11  1 6  1 4  1 21 70 144 92 21 6 1 14 9 10 ; .1  1 4  2 15  2 1  ~  1  —  17 17 11  1 — 14 ,1  OCTOBER 7 14 21 28  4 5  __ 1  1  —  —  1  1 —  7 11 12 16-16 12  9  1  1 — — - 1 1  1 —  —  Table I (cont'd.) MAY 6 13 20 27 Number o f samples P a g a s t i e l l a sp. A Tribelos protextus Chironomus modestus Cryptochironomus sp. A Cryptochironomus sp. B P o l y p e d i l i u m nubeculosum P o l y p e d i l i u m simulans H a r n i s c h i a amachaerus Harnischia galaptera Polypedilium tritum H a r n i s c h i a potamogeti Tribe Tanytarsini Lundstroemia sp. A Tanytarsus sp. C Stempellina bausei Tanytarsus~excavatus Z a v r e l i a sp. B Lundstroemia sp. B Tanytarsus sp. B Tanytarsus sp. A  18 27  27 18  JUNE 3 10 17 24 27 27  JULY 8  15  22 29  18 18  18  18  18  18  73 69 146 71 — 5 7 11 2 1 1 1  52 9 1  48 26 2  20 17  8 5  6 10 2  5 12  4 2 •-41 75 260 71 126 64  1 13  81 29 48 8 1 3 12 6  .__ —  3  AUGUST 5 12 19 26  9 18 8 7  1 2 17  5 — 8 10 10 22  1  18  SEPTEMBER 2 9 16 23 30  OCTOBER 7 14 21 28  9 13 10  6  8  1 3 5 1 — 6 1 — 3 1 25 30 10 10 1 2  4 4  9 18  26 39 9 15 20 2 1  12 6  20 7  12  15  8  3  8  20  24  29 14 21  8 11  18 102 282 345 190 93 67  11  7  7  7  3  1  — 9 4  1 2  6  7  5 19 17  4  1 3  —  1 1  2 1 1 14  1  —  1  ~  3 6  — 1  to to  Table I I .  Chironomid l a r v a e c o l l e c t e d i n Marion Lake w i t h t h e 225 cm^ Ekman dredge; v a l u e s c o r r e c t e d f o r l o s s o f l a r v a e through c o a r s e s i e v i n g s c r e e n . Sep  Number o f d r e d g i n g s  1963 Oct Nov  18  27  18  Dec  Jan  18  9  1 9 6 4 Feb Apr May  Jun  J u l Aug  9  27  18  18  18  18  62  346 7  285 117  273 136  371 38  392 32  S u b f a m i l y Tanypodinae P r o c l a d i u s spp. + Psilotanypus bellus AblabesmyTa~~monilis Pentaneurini sp. A + B + C Larsia acrocincta Clinotanypus sp. A Subfamily  1 3 6  2 3 3  1  2 1 3  9  1 9 3  2  1 0 6  53  1 7 1  33  c O  2 1  1  Orthocladinae  T r i s s o c l a d i u s sp. A H e t e r o t r i s s o c l a d i u s sp. A P a r a k i e f f e r i e l l a nigra P s e c t r o c l a d i u s sp. C + E Psectrocladius" sp. D H e t e r o t a n y t a r s u s sp. A P s e c t r o c l a d i u s sp. A Psectrocladius" sp. B Protanypus sp. A P s e c t r o c l a d i u s sp. G  7  15  118 7  5  -—  370 66  196 151  19  492  851  915  3 493  3  3  4  12  26  155 159 109 420 21  79 79 5 2 90 33 720 2 i X  11  4 27 11 202 25  4 2 2 13 28  35  38  5 76 5 2 2  43 13 44  5 197  7 137  5  5  T a b l e I I (cont'd.)  Number of d r e d g i n g s  1963  1964  Sep  Oct  Nov  Dec  Jan  Feb  Apr  May  Jun  Jul  Aug  18  27  18  18  9  9  27  18  18  18  18  17  26  7  15  13  22  22  11  2  44  6  4  24  14  20  20  3  21 10  22 1  90 8  82 1  136 7  199 7  139 3  318 178 9 8 142  559 154 10 15 145  727 241 69 36 152  588 74 65 38 117  465 69 79 30 63  912 248 98 46 201  14  14  13  8  3 9  30  S u b f a m i l y Chironominae Tribe Chironomini Chironomus spp. S e r g e n t i a sp. A ( s p r i n g emergence) S e r g e n t i a sp. A ( f a l l emergence) Microtendipes pedellus H a r n i s c h i a alphaeus P a g a s t i e l l a sp. A T r i b e l o s protextus Chironomus modestus Cryptochironomus spp. P o l y p e d i l i u m nubeculosum Polypedilium tritum + P o l y p e d i l i u m simulans H a r n i s c h i a amachaerus Harnischia galaptera H a r n i s c h i a potamogeti Tribe Tanytarsini Z a v r e l i a sp. A + Stempellina bausei Other T a n y t a r s i n i  18 31 2 6 20  94  128  508 116 68 35 167  1 458 163 34 15 102  1 406 7 52 4 71  158 2  244 2  424 27  -—  1 3 43  166  376  595  505  348  657  24  75 2 804 2 12 6 313 11 1  5  62  18  21  351  489  282  47  APPENDIX II TAXONOMY OF THE CHIRONOMIDAE OF MARION LAKE, BRITISH COLUMBIA  2 TABLE OF ^CONTENTS INTRODUCTION TO THE TAXONOMIC SECTION  4  TAXONOMIC TREATMENT  6  METHODS OF ASSOCIATING L I F E STAGES  13  PREPARATION AND EXAMINATION OF MATERIAL  14  TERMINOLOGY  17  DESCRIPTIONS  20  S u b f a m i l y TANYPODINAE  „  20  T r i b e TANYPODINI__  20  T r i b e MACROPELOPI INI  21  T r i b e COELOTANYPODI NI  34  T r i b e PENTANEURINI  36  S u b f a m i l y ORTHOCLADINAE  51  T r i b e PROTANYPINI  52  T r i b e ORTHOCL AD 11 NI  55  T r i b e METRIOCNEMINI  83  S u b f a m i l y CHIRONOMINAE__  91  T r i b e CHIRONOMINI  91  T r i b e TANYTARSINI  135  PROVISIONAL KEYS TO THE CHIRONOMIDAE OF MARION LAKE  178  LITERATURE CITED  210  INDEX TO TAXA  213  3 LIST OF FIGURES Figure 1. 2. 3. 4.  Page Taxonomic t e r m i n o l o g y Chironomidae  of the a d u l t , .  157  Taxonomic t e r m i n o l o g y Chironomidae .  o f the immature . . „—_  158  Key c h a r a c t e r s o f t h e Tanypodinae the M a c r o p e l o p i i n i  and 159  Key c h a r a c t e r s o f the M a c r o p e l o p i i n i and the C o e l o t a n y p o d i n i —  .—...  160  5.  Key c h a r a c t e r s o f the P e n t a n e u r i n i — .  6.  Key c h a r a c t e r s o f the P e n t a n e u r i n i  7.  Key c h a r a c t e r s o f the P r o t a n y p i n i and the O r t h o c l a d i i n i  161 ._.  162  .  163  .  8.  Key c h a r a c t e r s o f the O r t h o c l a d i i n i —  164  9.  Key c h a r a c t e r s o f t h e O r t h o c l a d i i n i -  165  10.  Key c h a r a c t e r s of t h e O r t h o c l a d i i n i  166  11.  Key c h a r a c t e r s o f the M e t r i o c n e m i n i  12.  Key c h a r a c t e r s o f the C h i r o n o m i n i  13.  Key c h a r a c t e r s of the C h i r o n o m i n i — .  14.  Key c h a r a c t e r s of the C h i r o n o m i n i - .  15.  Key c h a r a c t e r s o f t h e C h i r o n o m i n i —  16.  Key c h a r a c t e r s o f the C h i r o n o m i n i .  17.  Key c h a r a c t e r s o f t h e C h i r o n o m i n i —  18.  Key c h a r a c t e r s o f the T a n y t a r s i n i .  174  19.  Key c h a r a c t e r s o f the T a n y t a r s i n i —  175  20. 21.  Key c h a r a c t e r s o f the T a n y t a r s i n i - . . The wing v e n a t i o n o f s e l e c t e d M a r i o n Lake Chironomidae . . ——. .  176  .  167  .  168 169 .  170 171  «  .  172 .  173  177  4 INTRODUCTION TO THE The  TAXONOMIC SECTION  c h i r o n o m i c D i p t e r a t y p i c a l l y form a v e r y impor-  t a n t and e c o l o g i c a l l y d i v e r s e component of the bottom fauna of f r e s h water l a k e s .  However, because of the  difficulties  inherent i n separating morphologically s i m i l a r species there has been a tendency to c o n s i d e r them as an e c o l o g i c a l u n i t , a s i t u a t i o n t h a t i n v a r i a b l y l e a d s to a v a s t o v e r s i m p l i f i c a t i o n of the r o l e p l a y e d i n the ecology, of a l a k e .  In Marion  Lake, B r i t i s h Columbia more than h a l f of the bottom organisms c o l l e c t e d were members of t h i s f a m i l y and  i t was  f e l t that  the v a l u e of t h i s i n v e s t i g a t i o n would be much enhanced i f the s p e c i e s were s e p a r a t e d  and s t u d i e d i n d i v i d u a l l y .  done and i n a d d i t i o n each s p e c i e s i s t e n t a t i v e l y to f a c i l i t a t e comparisons w i t h the f i n d i n g s of authors.  This i s identified  previous  D e s c r i p t i o n s are i n c l u d e d f i r s t because the c h i r o n -  omid fauna of w e s t e r n Canada i s not w e l l known and second to b e t t e r enable o t h e r s to e v a l u a t e t h i s work. One  of the major d i f f i c u l t i e s encountered w h i l e  w o r k i n g on the s y s t e m a t i c s of t h i s f a m i l y was nearctic  fauna i s so p o o r l y known.  The  t h a t the  taxonomy i s based on  the a d u l t s which are q u i t e r e a d i l y o b t a i n a b l e , yet the o n l y adequate treatment  of a North American group i s Townes  monograph on the t r i b e C h i r o n o m i n i  (Townes, 1945).  Johann-  sen (1937a, 1937b) and Roback (1957) have d e a l t w i t h the  5 immature s t a g e s of the f a m i l y , but t h e i r monographs are based m a i n l y on m a t e r i a l c o l l e c t e d e a s t of the Rocky Mounta i n s and as a r e s u l t they do not i n c l u d e many of the s p e c i e s found i n M a r i o n Lake.  A l a r g e p r o p o r t i o n of the s p e c i e s  found i n the l a k e a r e new t o N o r t h America and o n l y 17 of the 48 s p e c i e s f o r which male imagos were a v a i l a b l e are b e l i e v e d t o have been p r e v i o u s l y r e p o r t e d from t h i s  contin-  ent . The European  l i t e r a t u r e i s more complete and an  i n t e r e s t i n g aspect of t h i s s t u d y has been the s i m i l a r i t y of the c h i r o n o m i d fauna i n B r i t a i n and S c a n d i n a v i a w i t h t h a t i n Marion Lake.  At l e a s t t h r e e of the genera encountered  o c c u r i n n o r t h e r n Europe but have not p r e v i o u s l y been r e c o r d e d from N o r t h A m e r i c a .  I n a d d i t i o n , t h e r e are t h r e e  s p e c i e s not p r e v i o u s l y r e c o r d e d from t h i s c o n t i n e n t which appear t o be the same as European s p e c i e s and s e v e r a l o t h e r s whose c l o s e s t known r e l a t i v e s are from Europe.  Ecological  d a t a such as depth p r e f e r e n c e and p e r i o d s of emergence u s u a l l y c o i n c i d e d v e r y c l o s e l y w i t h the p u b l i s h e d European m a t e r i a l and when such e v i d e n c e was a v a i l a b l e i t was i n t o account when making s p e c i f i c  taken  identifications.  A t o t a l of 51 s p e c i e s i n c l u d i n g 12 15 O r t h o c l a d i n a e and 24 Chironominae  Tanypodinae,  (16 C h i r o n o m i n i and 8  T a n y t a r s i n i ) are known t o o c c u r i n Marion Lake.  Forty-  6  e i g h t o f t h e s p e c i e s a r e d e s c r i b e d from a d u l t s and t h r e e o f them a r e d e s c r i b e d o n l y from immature s t a g e s .  Pupae a r e  a s s o c i a t e d w i t h 45 o f t h e a d u l t s and l a r v a e a r e d e f i n i t e l y o r almost d e f i n i t e l y a s s o c i a t e d w i t h 31 o f t h e a d u l t s . remaining  larvae described  a r e not o r a r e o n l y  The  tentatively  a s s o c i a t e d w i t h t h e a d u l t s and pupae. In most cases each d e s c r i p t i o n i s based on more than one specimen.  The f i r s t c o u n t , r a t i o o r measurement  under each major h e a d i n g i s f o l l o w e d by a b r a c k e t e d  number  which i n d i c a t e s t h e number o f specimens used t o o b t a i n t h e result.  Subsequent measurements and counts a r e not f o l l o w e d  by b r a c k e t e d  numbers u n l e s s t h e number o f specimens examined  d i f f e r s from t h e f i r s t for  indicated.  The measurements g i v e n  t h e l a r v a e a r e t a k e n from f o u r t h i n s t a r l a r v a e except  where i n d i c a t e d o t h e r w i s e .  A l l measurements a r e e x p r e s s e d  i n m i l l i m e t r e s e x c e p t f o r t h e segmental p r o p o r t i o n s o f t h e l a r v a l antenna.  The l a t t e r a r e r e c o r d e d  i n eye p i e c e u n i t s  which a t the m a g n i f i c a t i o n used, each e q u a l 1/400 mm.  TAXONOMIC TREATMENT The  c l a s s i f i c a t i o n o f t h e Chironomidae i s i n a  confused s t a t e .  A large part of t h i s confusion  i s due t o  7  the r e d i s c o v e r y o f Meigen's o r i g i n a l d e s c r i p t i o n s .  Recent  r u l i n g s by t h e I n t e r n a t i o n a l Congress o f Z o o l o g i c a l Nomenc l a t u r e have i n v a l i d a t e d some o f these o r i g i n a l names and have h e l p e d c l a r i f y t h e s i t u a t i o n , but p o i n t s o f c o n t e n t i o n s t i l l remain.  Major r e v i s i o n s o f the s u b f a m i l y  Orthocladinae  ( B r u n d i n , 1956) and t h e t r i b e s P e n t a n e u r i n i , A n a t o p y n i and M a c r o p e l o p i i n i ( F i t t k a u , 1962), have c o n s o l i d a t e d t h e m a t e r i a l and may h e l p s t a b i l i z e t h e nomenclature. The  c l a s s i f i c a t i o n and nomenclature used i n t h i s  a r t i c l e i s i n accordance w i t h the f o l l o w i n g monographs. Tanypodinae a r e c l a s s i f i e d a c c o r d i n g t o F i t t k a u Brundin's  The  (1962).  c l a s s i f i c a t i o n ( B r u n d i n , 1956) i s used f o r t h e  O r t h o c l a d i n a e and t h e T a n y t a r s i n i a r e c l a s s i f i e d  according  t o Freeman (1958, 1961).  Townes (1945) was t h e major r e f e r -  ence f o r t h e C h i r o n o m i n i  and h i s c l a s s i f i c a t i o n i s used, but  m o d i f i e d as f o l l o w s i n o r d e r t o comply w i t h subsequent r u l i n g s o f t h e I n t e r n a t i o n a l Congress o f Z o o l o g i c a l Nomenclature. The  t r i b e T e n d i p e d i n i and t h e genus Tendipes a r e r e p l a c e d by  Chironomini  and Chironomus r e s p e c t i v e l y . The genus  Tanytarsus  1 I n t h e year 1800 Meigen d e s c r i b e d a number o f s p e c i e s o f D i p t e r a and had h i s work p u b l i s h e d i n a s m a l l l i t t l e - k n o w n p u b l i c a t i o n . I n 1803 he p u b l i s h e d a more e x t e n s i v e work i n which he renamed and r e d e s c r i b e d many s p e c i e s covered by t h e e a r l i e r p u b l i c a t i o n . The names g i v e n i n t h e l a t t e r p u b l i c a t i o n were used f o r o v e r a c e n t u r y but i n t h e l a s t h a l f c e n t u r y many workers have used t h e e a r l i e r names r e s u l t i n g i n many synonomies.  8 i s r e s e r v e d f o r another ( B u l l . . Z o o l . Nom.  genus i n the T r i b e T a n y t a r s i n i  18: O p i n i o n 616).  p l a c e of the subgenus T a n y t a r s u s  and  S e r g e n t i a i s used i n i s g i v e n g e n e r i c rank  as are the o t h e r former subgenera of T a n y t a r s u s Lit.). cle  The  but was  (Oliver, in  genus P a g a s t i e l l a B r u n d i n i s used i n t h i s not i n c l u d e d i n Townes' monograph.  arti-  Finally  the  arrangement of the genera w i t h i n t h i s s u b f a m i l y f o l l o w s the more c o n s e r v a t i v e g e n e r i c o r d e r used by Roback  (1957).  The p r e v i o u s d e s c r i p t i o n s r e f e r r e d t o f o l l o w i n g each genus and p r e v i o u s l y d e s c r i b e d s p e c i e s are u s u a l l y not a complete l i s t .  Only the o r i g i n a l d e s c r i p t i o n s and u s u a l l y  one o r more o f the r e c e n t d e s c r i p t i o n s t h a t make r e f e r e n c e to p r e v i o u s d e s c r i p t i o n s and synonomies are i n c l u d e d . The  f o l l o w i n g t a x a are r e p r e s e n t e d  mid fauna o f M a r i o n L a k e , B r i t i s h Columbia.  i n the c h i r o n o The a s t e r i s k s  denote genera t h a t are not thought to have been p r e v i o u s l y r e p o r t e d from N o r t h A m e r i c a . Subfamily Tribe  Tanypodinae Tanypodini  Genus Tanypus Meigen Tanypus sp. A  9  Tribe  Macropelopiini  Genus P s i l o t a n y p u s  Kieffer  P s i l o t a n y p u s b e l l u s (Loew) Genus P r o c l a d i u s Skuse Procladius denticulatus Sublette P r o c l a d i u s freemani Sublette P r o c l a d i u s s p . A. Genus P s e c t r o t a n y p u s K i e f f e r Psectrotanypus v a r i u s (Fabricius) Tribe  Coelotanypodini  Genus C l i n o t a n y p u s Clinotanypus Tribe  Kieffer sp. A  Pentaneurini  Genus Thienemannimyia F i t t k a u Thienemannimyia s p . A Genus Z a v r e l i m y i a F i t t k a u Zavrelimyia sp. A Z a v r e l i m y i a sp. B Zavrelimyia sp. C Genus L a r s i a * F i t t k a u L a r s i a a c r o c i n c t a (Goetghebeur) Genus A b l a b e s m y i a Johannsen Ablabesmyia m o n i l i s  (Linnaeus)  Pentaneurini  sp. A  Pentaneurini  sp. B  Pentaneurini  sp. C  Subfamily Orthocladinae Tribe  Protanypini  Genus P r o t a n y p u s K i e f f e r Protanypus sp. A Tribe  Orthocladiini  Genus T r i s s o c l a d i u s K i e f f e r T r i s s o c l a d i u s sp. A Genus H e t e r o t r i s s o c l a d i u s Sparck H e t e r o t r i s s o c l a d i u s sp. A Genus H e t e r o t a n y t a r s u s * Sparck Heterotanytarsus sp. A Genus C r i c o t o p u s van d e r Wulp Cricotopus t r i c i n c t u s Genus P s e c t r o c l a d i u s  Kieffer  P s e c t r o c l a d i u s sp. A Psectrocladius sp. B P s e c t r o c l a d i u s sp. C P s e c t r o c l a d i u s sp. D P s e c t r o c l a d i u s sp. E P s e c t r o c l a d i u s sp. F P s e c t r o c l a d i u s sp. G  (Meigen)  11 Tribe Metriocnemini Genus P a r a k i e f f e r i e l l a Thienemann P a r a k i e f f e r i e l l a c o r o n a t a (Edwards) P a r a k i e f f e r i e l l a nigra Brundin Genus Corynoneura W i n n e r t z Corynoneura s p . A  S u b f a m i l y Chironominae Tribe Chironomini Genus Cryptochironomus K i e f f e r Cryptochironomus s p . A Cryptochironomus s p . B Genus H a r n i s c h i a K i e f f e r H a r n i s c h i a (Cladopelma) g a l a p t e r a Townes H a r n i s c h i a (Cladopelma) alphaeus S u b l e t t e H a r n i s c h i a ( H a r n i s c h i a ) potamogeti Townes H a r n i s c h i a ( H a r n i s c h i a ) amachaerus Townes Genus P a g a s t i e l l a * B r u n d i n P a g a s t i e l l a sp. A Genus M i c r o t e n d i p e s K i e f f e r M i c r o t e n d i p e s p e d e l l u s (De Geer) Genus Chironomus  Meigen  Chironomus  (Limnochironomus) modestus Say  Chironomus  (Chironomus) r e m p e l i i Thien.  Chironomus  (Chironomus) decorus Johannsen  12 Genus P o l y p e d i l i u m K i e f f e r P o l y p e d i l i u m ( P o l y p e d i l i u m ) nubeculosum (Meigen) P o l y p e d i l i u m (Pentapedilium) t r i t u m (Walker) P o l y p e d i l i u m ( T r i p o d u r a ) s i m u l a n s Townes Genus S e r g e n t i a K i e f f e r Sergentia sp. A Genus T r i b e l o s Townes T r i b e l o s p r o t e x t u s (Townes) Tribe Tanytarsini Genus Z a v r e l i a K i e f f e r Z a v r e l i a sp. A Genus S t e m p e l l i n a Bause Stempellina bausei  (Kieffer)  Genus L u n d s t r o e m i a K i e f f e r Lundstroemia sp. A Lundstroemia sp. B Genus T a n y t a r s u s van d e r Wulp Tanytarsus  (Tanytarsus) sp. A  Tanytarsus  (Tanytarsus) sp. B  Tanytarsus  (Tanytarsus) sp. C  Tanytarsus  ( T a n y t a r s u s ) excavatus Edwards  T a n y t a r s i n i sp. A  13 METHODS OF ASSOCIATING L I F E STAGES The most s a t i s f a c t o r y method o f a s s o c i a t i n g t h e l a r v a , pupa and a d u l t o f a g i v e n s p e c i e s i s by r e a r i n g . t h i s study only f o u r t h i n s t a r larvae nearing pupation chosen f o r t h i s purpose.  In  were  They were kept i n d i v i d u a l l y i n two  o r f o u r dram v i a l s which were h a l f f i l l e d w i t h l a k e w a t e r and c o n t a i n e d  a s m a l l p i e c e o f non-absorbent s t y r o f o a m f o r  the a d u l t t o s e t t l e on.  The v i a l s were c l o s e d w i t h a wad o f  c o t t o n b a t t e n and immersed i n a water b a t h kept a t a p p r o x i m a t e l y 17°C.  The a d u l t s o f 16 Marion Lake s p e c i e s have been  a s s o c i a t e d w i t h t h e i r l a r v a l and p u p a l e x u v i a e i n t h i s manner. Other methods o f a s s o c i a t i n g l i f e s t a g e s  are l e s s  d i r e c t , b u t when enough e v i d e n c e i s a v a i l a b l e near p o s i t i v e a s s o c i a t i o n s can be e s t a b l i s h e d .  The t h r e e main c a t e g o r i e s  o f s u p p o r t i n g e v i d e n c e used i n t h i s study were t h e morpholo g i c a l , t h e e c o l o g i c a l and t h e l i t e r a t u r e . morphological  A piece of  e v i d e n c e o f t e n used t o a s s o c i a t e t h e l a r v a e and  pupae i s t h a t l a r v a e n e a r i n g p u p a t i o n  have p u p a l r e s p i r a t o r y  organs which a r e o f t e n v i s i b l e w i t h i n t h e t h o r a x , a f t e r t h e a n i m a l has been macerated w i t h KOH.  In a d d i t i o n , the pupal  markings o f t h e abdominal t e r g i t e s o f some o f t h e T a n y t a r s i n i are v i s i b l e through t h e t e r g i t e s o f t h e l a r v a p r i o r t o pupat i o n o r o c c a s i o n a l l y t h e l a r v a l e x u v i a remains a t t a c h e d t o  14 the pupa. . The pupae were r e l a t i v e l y easy t o a s s o c i a t e  with  the a d u l t s f i r s t because t h e hypopygium o f t h e male imago i s v i s i b l e through t h e pupa and second because most o f t h e a d u l t s and p u p a l e x u v i a e were c o l l e c t e d t o g e t h e r merged f u n n e l The  i n sub-  traps. e c o l o g i c a l evidence c o n s i s t e d of r e l a t i n g the  d e n s i t y , d i s t r i b u t i o n and d a t e s o f p u p a t i o n o f t h e l a r v a e w i t h t h e d a t a on a d u l t emergence..  F i n a l l y t h e specimens  were compared w i t h p r e v i o u s d e s c r i p t i o n s and when t h e l a r v a , pupa and a d u l t a l l keyed t o t h e same s p e c i e s o r i n some c a s e s even t h e same genus t h i s was c o n s i d e r e d strong supporting  evidence.  as v e r y  I n n e a r l y e v e r y case  to t h e l i t e r a t u r e s u b s t a n t i a t e d  the morphological  reference and e c o l -  o g i c a l evidence.  PREPARATION AND EXAMINATION OF MATERIAL When they were a v a i l a b l e , p i n n e d specimens and those p r e s e r v e d d r y i n v i a l s were used f o r c o l o r d e t e r m i n a t i o n as t h e c o l o r s o f a l c o h o l p r e s e r v e d specimens fade r a p i d l y making d e t a i l e d d e s c r i p t i o n s o f c o l o r impossible.  T h i s may not be o f much importance however,  s i n c e many workers now c o n s i d e r overestimated  patterns  t h a t c o l o r has been,much  as a taxonomic c h a r a c t e r  and they r e l y almost  e n t i r e l y on s t r u c t u r a l d e t a i l s as i n d i c a t o r s o f taxonomic  15 p o s i t i o n ( B r u n d i n , 1956).  The a u t h o r ' s e x p e r i e n c e  many o f these s t r u c t u r a l d e t a i l s can not be seen  i s that adequately  u n l e s s t h e specimen i s mounted on a s l i d e . Most o f t h e s l i d e p r e p a r a t i o n s were made f o l l o w i n g a method m o d i f i e d from one suggested (in  by D r . D. R. O l i v e r  Lit.). The wings of a d u l t s p r e s e r v e d  i n 7 0 % e t h a n o l were  removed and t r a n s f e r r e d through one t o t h r e e p r o g r e s s i v e l y increasing concentrations of ethanol u n t i l a concentration of 100% was r e a c h e d .  They were then t r a n s f e r r e d t o cedar  wood o i l f o r about f i v e minutes b e f o r e mounting i n Canada balsam u s i n g a c o v e r s l i p 10-12 mm. i n d i a m e t e r . The remainder o f t h e a d u l t was t r e a t e d as f o l lows.  A l l s t e p s were c a r r i e d o u t a t room temperature and  the time spent a t each c o u l d be v a r i e d c o n s i d e r a b l y w i t h o u t any n o t i c e a b l e h a r m f u l 1.  effects.  Macerated i n c o l d 10% KOH f o r 24 h o u r s .  2. . P l a c e d i n g l a c i a l a c e t i c a c i d f o r 15 m i n u t e s . 3.  P l a c e d i n two r i n s e s o f a b s o l u t e e t h a n o l f o r 15 minutes each.  4.  Placed i n a v i a l containing absolute ethanol layered o v e r cedar wood o i l u n t i l t h e specimen had s e t t l e d  16 to t h e bottom o f t h e o i l . 5.  C l e a r e d i n c e d a r wood o i l f o r 15 m i n u t e s .  6.  Mounted  i n Canada balsam.  The antenna, head and hypopygium were mounted under a s i n g l e c o v e r s l i p and on t h e same s l i d e as t h e w i n g s . Care was t a k e n t o mount t h e head and hypopygium d o r s a l s i d e up.  The t h o r a x , l e g s and abdomen were mounted r i g h t s i d e up  under a t h i r d c o v e r s l i p . Most o f t h e p u p a l e x u v i a e and t h e l a r v a e o f the O r t h o c l a d i n a e and Chironominae were mounted f o l l o w i n g t h e method o u t l i n e d f o r t h e wings w h i l e t h e pupae and l a r v a l Tanypodinae were t r e a t e d l i k e t h e body o f the a d u l t .  The  pupae and p u p a l e x u v i a e were mounted d o r s a l s i d e up.  The  l a r v a e were d e c a p i t a t e d p r i o r t o mounting.  Each head was  mounted v e n t r a l s i d e up under one c o v e r s l i p and t h e approp r i a t e t h o r a x and abdomen was p l a c e d on i t s s i d e under a second c o v e r s l i p . A second method o f mounting specimens was t o t r a n s fer  them t o d i s t i l l e d w a t e r e i t h e r from a l c o h o l o r from 10%  KOH and t h e n mount d i r e c t l y i n T u r t o x CMC-10. are  much q u i c k e r t o p r e p a r e and when r i n g e d appear t o be  permanent. of  Such s l i d e s  An a d d i t i o n a l advantage i s t h a t a s m a l l amount  s t a i n such as f a s t green can be added t o t h e medium  17 r e s u l t i n g i n some c h a r a c t e r s , p a r t i c u l a r l y t h e wing  venation,  b e i n g much e a s i e r t o s e e .  TERMINOLOGY Most o f t h e m o r p h o l o g i c a l  characters referred to  i n t h i s a r t i c l e a r e i l l u s t r a t e d i n F i g u r e s 1-A t o 2-E but the f o l l o w i n g e x p l a n a t i o n s  are included to help e l i m i n a t e  confusion. The t e r m i n o l o g y  o f t h e wing v e n a t i o n  based on t h e o r i g i n a l Comstock-Needham system.  ( F i g . 1-D) i s Several  r e c e n t a u t h o r s have adopted T i l l y a r d ' s m o d i f i c a t i o n o f t h i s system but L i n d e b e r g  (1964) g i v e s e v i d e n c e s u g g e s t i n g  that  t h i s m o d i f i c a t i o n i s not a p p l i c a b l e t o t h e Chironomidae and he f e e l s t h a t Edwards' i n t e r p r e t a t i o n o f t h e o r i g i n a l system (Edwards, 1929). i s best r e t a i n e d .  The wing h a i r s a r e d e s i g -  nated as m a c r o t r i c h i a o r m i c r o t r i c h i a . The m a c r o t r i c h i a r e f e r t o t h e l a r g e r h a i r s e a s i l y seen a t a m a g n i f i c a t i o n o f 40-100 and m i c r o t r i c h i a r e f e r t o t h e s m a l l e r h a i r s t h a t r e q u i r e a m a g n i f i c a t i o n o f a t l e a s t 200 and more o f t e n 4001000 t o be seen.  The wing l e n g t h was t a k e n from t h e wing  apex t o t h e a r c u l u s , t h e prominent c r o s s - v e i n  approximately  l e v e l w i t h t h e j u n c t i o n o f t h e main p a r t o f t h e wing w i t h the  alula. The c h a e t o t a x i s o f t h e a d u l t t h o r a x  ( F i g . 1-C) i s  18 essentially  t h a t used by O l i v e r (1959).  Two  r a t i o s f r e q u e n t l y used i n c h i r o n o m i d taxonomy  are the l e g r a t i o  (= L.R.)  which i s the l e n g t h of the i  fore  b a s i t a r s u s d i v i d e d by the l e n g t h of the f o r e t i b i a and antennal r a t i o  (= A.R.)  which i s the l e n g t h of the  the  terminal  segment d i v i d e d by the combined l e n g t h of the b a s a l segments of the f l a g e l l u m .  I n the case of the Tanypodinae the  o f the s h o r t t e r m i n a l and  lengths  l o n g p r e a p i c a l segment are both  i n c l u d e d i n the numerator. The  presence o r absence of a t a r s a l beard i s o f t e n  of taxonomic i m p o r t a n c e .  T h i s beard ( F i g . 1-B)  c o n s i s t s of  l o n g h a i r s t h a t are i n a d d i t i o n to the s h o r t h a i r s t h a t always p r e s e n t on the  are  tarsus.  Some of the s t r u c t u r e s of the hypopygium ( F i g . t h a t are used as taxonomic c h a r a c t e r s the c o x i t e and  the s t y l e .  The  are the a n a l p o i n t ,  l a t t e r two  s t r u c t u r e s have  been r e f e r r e d t o by some a u t h o r s as t h e - s t y l e and tistyle respectively. lobes.  The  1-E)  the d i s -  c o x i t e o f t e n has d i s t i n c t i v e  These c o n s i s t of a s u p e r i o r and  basal  an i n f e r i o r appendage  which i n the case of the T a n y t a r s i n i o f t e n each have an accessory  appendage.  are d e s i g n a t e d The  I n t h i s paper the a c c e s s o r y  appendages  as appendages l a and 2a r e s p e c t i v e l y . term t e r g i t e and s t e r n i t e r e f e r r e s p e c t i v e l y  19 to t h e upper and lower s u r f a c e s o f each segment. i s g e n e r a l throughout t h e c h i r o n o m i d t h i s r e a s o n t h e usage i s c o n t i n u e d speaking,  T h e i r use  l i t e r a t u r e and f o r  here a l t h o u g h  strictly  t h e c o r r e c t terms a r e tergum and sternum. The  s p i n u l e s on t h e abdominal t e r g i t e s o f t h e pupa  are o f v a r i o u s s i z e s and o f t e n a r e arranged i n c h a r a c t e r i s t i c "shagreen" p a t t e r n s . the pupa i s u s u a l l y m o d i f i e d  The l a s t abdominal segment o f i n t o a c h a r a c t e r i s t i c swim f i n  c o n s i s t i n g o f two o f t e n f r i n g e d  a n a l l o b e s and two g e n i t a l  lobes. The head c a p s u l e of t h e l a r v a has a number o f s t r u c t u r e s which a r e o f t e n used as taxonomic  indicators.  Most o f these c h a r a c t e r s a r e i l l u s t r a t e d i n F i g u r e s 2-A and 2-B.  O t h e r s i n c l u d e t h e shape, s i z e and l o c a t i o n o f t h e  eye s p o t s and the shape o f t h e l a b r a l b r i s t l e s .  In the  case o f t h e Tanypodinae use i s o f t e n made o f the a n t e n n a l ratio  (= A.R.) which i s the r a t i o o f t h e l e n g t h o f t h e b a s a l  segment t o t h e combined l e n g t h o f t h e t e r m i n a l segments. A species i s designated  as abundant i f t h e den-  s i t y o f i n d i v i d u a l s p e r square metre i s more t h a n  250,common  i f i t i s between 25 and 249 and r a r e i f i t i s l e s s than 25.  20 DESCRIPTIONS Subfamily  TANYPODINAE  A d u l t s of t h i s f a m i l y are c h a r a c t e r i z e d by  the  p r e s e n c e of v e i n R 2 , a s m a l l c r o s s - v e i n which j o i n s R i ^2+3  n  e  a  r  t h e i r apices.  always p r e s e n t  and  and  I n a d d i t i o n , the c r o s s - v e i n m-cu  the c o x i t e of the hypopygium l a c k s  o r appendages.  The  t o r y organs and  the a n a l l o b e s n o r m a l l y  is  lobes  pupae have s i m p l e non-branched r e s p i r a -  l a t e r a l b r i s t l e s or f i l a m e n t s .  The  have two p a i r s of  l a r v a e have l o n g r e t r a c -  t i l e antennae and r e l a t i v e l y l a r g e heads w i t h u n i t e d , commonly r e n i f o r m e y e s p o t s .  The  mandibles have a l a r g e a p i c a l  t o o t h and u s u a l l y one o r more minute l a t e r a l s . pharynx has subfamily  a characteristic lingua.  are u s u a l l y f r e e l i v i n g  The  The  l a r v a e of  hypothis  predators.  At l e a s t 13 s p e c i e s o c c u r i n Marion Lake.  Usually  the l a r v a e of a p a r t i c u l a r s p e c i e s are w i d e l y d i s t r i b u t e d w i t h i n the l a k e and the a d u l t s u s u a l l y emerge o v e r a p e r i o d of s e v e r a l months.  T r i b e TANYPODINI Genus TANYPUS Meigen Tanypus Meigen, 1803, Tanypus Edwards, 1929,  I l l i g e r s Mag.  f . I n s e c t e n k d e . p.  261.  T r a n s , e n t . Soc. Lond. 77:299.  A s i n g l e s p e c i e s i s known to o c c u r i n M a r i o n Lake.  21 Tanypus sp. A The and  l a r v a and  a d u l t of t h i s s p e c i e s are unknown  the s i n g l e f e m a l e pupa a v a i l a b l e was  suitable for specific P u p a : — l e n g t h 6.1  not i n a c o n d i t i o n  identification.  mm.;  r e s p i r a t o r y organ l o s t .  t e r g i t e s u n i f o r m l y shagreened; segments I to VI  Abdomen: without  l a t e r a l f i l a m e n t s ; l a t e r a l f i l a m e n t s on segments V I I V I I I 5-5;  a n a l l o b e s ( F i g . 3-A)  much r e d u c e d , each w i t h  l a r g e f i l a m e n t s and w i t h o u t m a r g i n a l Ecology:—  a s i n g l e pupa was  a d e p t h of 3.5  and two  spines.  c o l l e c t e d F e b r u a r y 12, 1964  at  metres.  M a t e r i a l e x a m i n e d : — 1? pupa 12.11.64.  Marion Lake,  B.C.  T r i b e MACROPELOPIINI Genus PSILOTANYPUS K i e f f e r P s i l o t a n y p u s K i e f f e r , 1906,  i n WYTSMAN, G e n e r a l  Insectorum.  42:34. P r o c l a d i u s (subg. P s i l o t a n y p u s ) Edwards, 1929,  Trans, ent.  Soc. Lond. 77:301-302. One genus.  s p e c i e s from M a r i o n Lake came under t h i s  22 P s i l o t a n y p u s b e l l u s (Loew) Tanypus b e l l u s Loew, 1866, Protenthes  B e r l . e n t . Z.  b e l l u s M a l l o c h , 1915,  10:4.  B u l l . 111. S t . Lab.  nat.  H i s t . 10:388 P r o c l a d i u s b e l l u s S u b l e t t e , 1964,  P r o c . U.S.  natn.  Mus.  115:126 T h i s s p e c i e s was  not r e a r e d but the l a r v a i s  almost c e r t a i n l y c o r r e c t l y a s s o c i a t e d .  The  a d u l t male and  the immature s t a g e s a l l agree w e l l w i t h p u b l i s h e d d e s c r i p t i o n s and  t h e r e i s l i t t l e doubt t h a t the Marion Lake s p e c i -  mens are P.  bellus.  Male i m a g o : — b r o w n i s h , abdominal segments I I I , IV and VI to V I I I brownish b l a c k and much d a r k e r than a d j a c e n t Antenna: A.R.  segments.  1.50-1.69(2), f l a g e l l u m w i t h 14 segments.  Head: p a l p p r o p o r t i o n s 5:8:9:15; c l y p e u s w i t h 14 o r  15  b r i s t l e s ; t e m p o r a l h a i r s i n s i n g l e rows which extend t o p o i n t s midway between v e r t e x angles of eyes and mid head.  Thorax: pronotum w i t h 2 o r 3 f i n e b r i s t l e s ;  central bristles and  13 i n a s i n g l e row;  l i n e of dorso-  supra-alar b r i s t l e s  4  a single*post-alar b r i s t l e ; scutellum with a s i n g l e  t r a n s v e r s e row of b r i s t l e s .  Wing: l e n g t h 1.40-1.55;  m a c r o t r i c h i a p r e s e n t on o u t e r p a r t of wing membrane but very sparse; C extending c r o s s - v e i n r-m  0.08  mm.  beyond j u n c t i o n of R4+5;  surrounded by a p a t c h of d a r k brown.  Legs:  23 L.R.  0.62-0.63, f o r e t i b i a w i t h a s i n g l e s p u r about as  long  as w i d t h of t i b i a at apex, s p u r w i t h 5 l a t e r a l s p i n e s ; f o r e tarsus without and 0.03  mm.  a b e a r d ; m i d d l e t i b i a w i t h s p u r s about  0.04  l o n g , each w i t h 4 o r 5 l a t e r a l t e e t h ; h i n d  t i b i a w i t h s p u r s about 0.043 and 0.033 mm. comb w i t h 11 s p i n e s .  long;  Hypopygium: ( F i g . 3-B)  tibial  d i s t a l end  of  s t y l e narrow and s l i g h t l y c u r v e d , p o s t e r i o r p r o j e c t i o n of s t y l e reduced. P u p a : — l e n g t h 3.6-3.7 mm.(3), e x u v i a l i g h t brown. p i r a t o r y organ ( F i g . 3-C)  0.27-0.28 mm.  Res-  l o n g and 0.05-0.06  mm.  wide.  mm.  l o n g ; t e r g i t e I I to V I I I u n i f o r m l y shagreened; a n a l  lobes  Abdomen: t e r g i t e I w i t h a median r i d g e 0.11-0.12  ( F i g . 3-D)  each w i t h two  m a r g i n a l s p i n e s and w i t h o u t Larva:— ( F i g . 3-F)  l a t e r a l f i l a m e n t s , 19-21  a caudo-mesal s p u r .  l i g h t coloured,, maximum l e n g t h 7 mm.  Antenna:  b a s a l segment 0.115-0.135 mm.(6) l o n g .  l e n g t h 0.46-0.50; eye s p o t s form; l i n g u a ( F i g . 3-G)  long  ( F i g . 3-E)  Head:  connected and  reni-  w i t h 5 dark t e e t h , the m i d d l e  one  the s m a l l e s t ; s u p e r l i n g u a  ( F i g . 3-G)  with 1 or 2 inner  s p i n e s , a l o n g a p i c a l and  5 or 6 outer spines; pecten with 7  o r 8 s p i n e s p e r s i d e ; p a r a l a b i a l comb ( F i g . 3-H)  with 6 or 7  d a r k t e e t h and a l i g h t m e d i a l t o o t h ; mandible ( F i g . w i t h a l o n g dark a p i c a l t o o t h , a l i g h t curved and a minute a c c e s s o r y  tooth.  lateral  Abdomen: a n a l p a p i l l a  3-1) tooth tubular,  24 0.15  mm.  l o n g and 0.03  mm.  wide and w i t h at l e a s t 11 a p i c a l  b r i s t l e s ; a n a l g i l l s c o n i c a l , about 0.13 mm.  mm.  l o n g and  wide at base;, p o s t e r i o r p r o l e g s about 0.42  Ecology:—  mm.  0.03  long.  l a r v a e o f t h i s s p e c i e s were common a t a l l depths  but o c c u r r e d l e s s f r e q u e n t l y below 4 m e t r e s .  I n 1964  emergence of t h i s s p e c i e s took p l a c e between J u l y 15  the and  September 15. M a t e r i a l e x a m i n e d : — lo", 2 3 . V I I I . 6 4 ; 23.VIII.64;  5 l a r v . , 21.VIII.64,  lo", 2.IX.64; 3  Marion L a k e ,  pup.,  B.C.  Genus PROCLADIUS Skuse P r o c l a d i u s Skuse, 1889,  P r o c . L i n n . Soc. N.S.W. (2) 4:283  P r o c l a d i u s subg. P r o c l a d i u s Edwards, 1929,  Trans, ent.  Soc.  Lond. 77:301 T h i s genus i s w e l l r e p r e s e n t e d  i n Marion Lake.  At l e a s t t h r e e s p e c i e s are known t o o c c u r .  Procladius denticulatus Sublette P r o c l a d i u s d e n t i c u l a t u s S u b l e t t e , 1964, Mus.  P r o c . U.S.  nata.  115:124-126  T h i s s p e c i e s was  not r e a r e d but the l a r v a i s  almost c e r t a i n l y c o r r e c t l y a s s o c i a t e d .  The  specimens f r o m  25 M a r i o n Lake are p r o b a b l y  P. d e n t i c u l a t u s .  The  s t y l e of  hypopygium i s v e r y s i m i l a r to t h a t of the p a r a t y p e and median i n t e r n a l s t r u t a t the base of the c o x i t e has spicuous  the  con-  d e n t i c l e s , a suggested d i a g n o s t i c c h a r a c t e r i s t i c  of the s p e c i e s . A.R.,  the  A d u l t males from M a r i o n Lake have a h i g h e r  a lower L.R.,  and  the m e d i a l margin of the c o x i t e  l a c k s the s m a l l l o b e i l l u s t r a t e d by S u b l e t t e (1964b). a d u l t keys to P. c u l i c i f o r m i s Townes (1952) and  (Linnaeus)  The  i n Johannsen  and  the pupa keys P. c u l i c i f o r m i s i n Roback  (1957); however, S u b l e t t e t h i n k s t h a t the specimens of Johannsen and Townes are i n f a c t P. d e n t i c u l a t u s . Male i m a g o : — b r o w n i s h b l a c k .  Antenna: A.R.  2 . 2 4 ( 3 ) , f l a g e l l u m w i t h 14 segments. t i o n s 8:12:17:22; c l y p e u s w i t h 11-14  2.06-2.40 mean  Head: p a l p bristles;  propor-  temporal  h a i r s i n a s i n g l e row m e d i a l l y and  i n an i r r e g u l a r double  a l o n g the l a t e r a l margin of head.  Thorax: pronotum w i t h  row  about 16 f i n e b r i s t l e s ; d o r s o - c e n t r a l b r i s t l e s 22-27 i n a s i n g l e row;  supra-alar b r i s t l e s  14-19  and  a l a r b r i s t l e ; p r e s c u t e l l a r b r i s t l e s 3-5;  a s i n g l e postscutellum with a  s i n g l e t r a n s v e r s e row of b r i s t l e s near the l a t e r a l margin and numerous s c a t t e r e d b r i s t l e s l e n g t h 2.4-2.6 mm.; C extending L.R.  i n the median a r e a .  Wing:  wing membrane w i t h numerous m a c r o t r i c h i a ;  about 0.15  mm.  0.74-0.79 mean 0.77;  beyond j u n c t i o n of R4+5.  Legs:  f o r e t i b i a l s p u r about as l o n g  w i d t h of t i b i a at apex and w i t h 4 o r 5 l a t e r a l t e e t h ;  as  26 t a r s a l beard s p a r s e o r absent; m i d d l e l e g t i b i a l about 0.07  and 0.06  mm.  spurs  l o n g , each w i t h 5 l a t e r a l t e e t h ;  h i n d l e g t i b i a w i t h s p u r s about 0.08  and 0.06  mm.  long,  each w i t h 6 l a t e r a l t e e t h ; p r e a p i c a l comb of t i b i a w i t h spines.  11  Hypopygium: ( F i g . 3 - J ) ; p o s t e r i o r p r o j e c t i o n of  s t y l e p r o m i n e n t , about 3.5  t i m e s i n t o t o t a l l e n g t h of  style;  median i n t e r n a l s t r u t at base of c o x i t e w i t h c o n s p i c u o u s d e n t i c l e s at apex. P u p a : — l e n g t h 5.8-7.1 mm.(5), e x u v i a dark brown. p i r a t o r y organ: ( F i g . 3-L)  0.44-0.56 mm.  Res-  l o n g and 0.13-0.18  mm.  wide.  Abdomen: t e r g i t e I w i t h a median s c a r 0.20-0.23  mm.  l o n g ; t e r g i t e I I t o V I I I u n i f o r m l y shagreened; a n a l  l o b e s (Fig.. 3-K)  each w i t h 2 l a t e r a l f i l a m e n t s , 27-36  c o a r s e m a r g i n a l s p i n e s and a caudo-mesal s p u r . Larva:—  y e l l o w i s h , maximum l e n g t h 10 mm.  of b a s a l segment 0.18-0.19 mm.(5). mm.;  ble  superlingua  i n n e r s p i n e s , a l o n g a p i c a l and 3-5  p e c t e n w i t h 12-14 3-M)  Head: l e n g t h 0.84-0.97  e y e s p o t s connected and r e n i f o r m ; l i n g u a v e r y s i m i l a r  to t h a t shown i n F i g u r e 3-S; 1-2  Antenna: l e n g t h  w i t h 7-8  ( F i g . 3-N)  with  l a t e r a l spines;  s p i n e s p e r s i d e ; p a r a l a b i a l comb ( F i g .  d a r k t e e t h and a l i g h t median t o o t h ; mandi-  s i m i l a r to t h a t shown i n F i g u r e 3-U.  Abdomen: a n a l  p a p i l l a t u b u l a r about 4 t i m e s as l o n g as broad and w i t h a p i c a l b r i s t l e s ; a n a l g i l l s t a p e r i n g t o a p o i n t and  14  about  27 0.24 mm.  long.  E c o l o g y : — l a r v a e o f t h i s s p e c i e s a r e common o r abundant a t a l l depths i n M a r i o n Lake.  I n 1964 emergence l a s t e d from  mid June u n t i l e a r l y O c t o b e r . M a t e r i a l examined:—  4o"o" ?. VI11.64; 3 pup. exuv., 10. V I I I . ?  64; 2 pup. exuv., 20.VI.64;  5 l a r v . , 22.VII.64, M a r i o n  Lake, B.C.  P r o c l a d i u s freemani Sublette P r o c l a d i u s f r e e m a n i S u b l e t t e , 1964, P r o c . U.S. n a t n . Mus. 115:122-123 T h i s s p e c i e s was r e a r e d .  The specimens  from  M a r i o n Lake agree w e l l w i t h S u b l e t t e s ' d e s c r i p t i o n and probably are t h i s species.  A d u l t males key t o P. choreus  (Meigen) i n Johannsen and Townes (1952) and i n M a l l o c h (1915).  The pupa a r e s i m i l a r t o those o f P. choreus des-  c r i b e d by Roback (1957) and by Johannsen  (1937a). but have  45-53 m a r g i n a l s p i n e s on t h e a n a l f i n r a t h e r than 33-40.  A  second r e a s o n f o r not i d e n t i f y i n g my specimens as P. choreus i s t h a t t h e v a l i d i t y o f t h e s p e c i e s i s i n doubt  (Sublette,  1964b). Male i m a g o : — t h o r a x and abdomen b l a c k i s h brown, l e g s and antennae d a r k brown.  Antenna: A.R. 2.14-2.54 mean 2 . 3 8 ( 4 ) ,  28 f l a g e l l u m w i t h 14 segments. 16:21; c l y p e u s w i t h 19-30  Head: p a l p p r o p o r t i o n s 10:14:  b r i s t l e s ( 3 ) ; temporal h a i r s i n  i r r e g u l a r d o u b l e rows which extend to p o i n t s about 3/4  of  the d i s t a n c e from the v e r t e x a n g l e s of the eyes t o the midl i n e of head.  Thorax:, pronotum w i t h 20-23 b r i s t l e s ; d o r s o  c e n t r a l b r i s t l e s i n a s i n g l e row; i n a s i n g l e row;  p o s t - a l a r b r i s t l e s 1-2;  i n a s i n g l e t r a n s v e r s e row ted near m i d l i n e . (3); C extending r-m  supra-alar b r i s t l e s  scutellum, b r i s t l e s  l a t e r a l l y and randomly d i s t r i b u -  Wing: ( F i g . 23-A); l e n g t h 2.6-2.65 0.12  mm.  Legs: L.R.  0.74-0.76; f o r e  t i b i a w i t h an a p i c a l s p u r about as l o n g as w i d t h of at apex; f o r e t a r s u s w i t h a s p a r s e b e a r d ; m i d d l e and 0.06  mm.  p a s t j u n c t i o n of R4+5; c r o s s - v e i n  surrounded by a d a r k p a t c h .  s p u r s about 0.07  17-23  mm.  tibia  tibial  l o n g and each w i t h 5 l a t e r a l  t e e t h ; h i n d t i b i a l s p u r s about 0.075 and 0.06  mm.  long  and  each w i t h 5 l a t e r a l t e e t h ; p r e a p i c a l comb of t i b i a w i t h spines.  Hypopygium: ( F i g . 3-0)  s t y l e q u i t e prominent, about 5.7  11  p o s t e r i o r p r o j e c t i o n of times i n t o t o t a l l e n g t h of  s t y l e ; s t r u t s at base of c o x i t e s w i t h o u t comspicuous d e n t i cles . P u p a : — l e n g t h 6.4-6.9 mm.(4), e x u v i a b r o w n i s h . organ: ( F i g . 3-P)  0.52-0.60 mm.  Respiratory  l o n g and 0.18-0.22 mm.  Abdomen: t e r g i t e I w i t h a median s c a r about 0.22  mm.  t e r g i t e s I I to V I I I u n i f o r m l y shagreened; each a n a l ( F i g . 3-Q)  w i t h 2 l a t e r a l f i l a m e n t s , 45-53 f i n e  wide. long;  lobe  marginal  29  s p i n e s and a caudo-mesal s p u r . Larva:—  y e l l o w w i t h brown f l e c k s , maximum l e n g t h 10  Antenna l e n g t h of b a s a l segment 0.175-0.19 mm.(5). l e n g t h 0.81-0.85; l i n g u a ( T i g . 3-S) median one  the s h o r t e s t ; s u p e r l i n g u a  mm. Head  w i t h 5 d a r k t e e t h , the ( F i g . 3-S)  with  1-2  i n n e r s p i n e s , a l o n g a p i c a l and 4 o r 5 o u t e r s p i n e s ; p e c t e n w i t h 11 to 15 s p i n e s per s i d e ; p a r a l a b i a l comb ( F i g . w i t h 7-9 3-U)  dark t e e t h and a l i g h t m e d i a l t o o t h ; mandible ( F i g .  w i t h a l o n g d a r k a p i c a l , a l i g h t curved  minute a c c e s s o r y about 0.2 mm.  mm.  tooth.  mm.  l a t e r a l and  a  Abdomen: a n a l p a p i l l a t u b u l a r ,  l o n g and 0.04  l o n g and 0.06  Ecology:—  mm.  wide; a n a l g i l l s about  0.2  wide at base, t a p e r i n g to a p o i n t .  B e n t h i c l a r v a e are common o r abundant at a l l  depths i n M a r i o n Lake. and  3-T)  I n 1964  emergence took p l a c e i n  May  June.  Material examined:— 4.V.64; 3 pup.  „8.V.65; ',3&<f, 7.V.64; 1 pup.  exuv.,  exuv., 24.V.64; 5 l a r v . , 27.V.64, Marion Lake,  B.C.  P r o c l a d i u s sp. A T h i s s p e c i e s was  not r e a r e d , but the l a r v a i s  almost c e r t a i n l y c o r r e c t l y a s s o c i a t e d .  The v e r y l a r g e s i z e  of the a d u l t male and the shape of the s t y l e w i l l  separate  30 i t f r o m any of the d e s c r i b e d species.known t o the  author.  The pupa a l s o has an u n u s u a l l y l a r g e number of s p i n e s on  the  anal lobes. Male i m a g o : — b l a c k . 14 segments.  Antenna A.R.  3.65(1), f l a g e l l u m w i t h  Head: p a l p p r o p o r t i o n s 10:20:24:33; c l y p e u s  w i t h 37 b r i s t l e s ; t e m p o r a l h a i r s i n 2-3 extend t o p o i n t s about 3/4  i r r e g u l a r rows which  of the d i s t a n c e s from the v e r t e x  a n g l e s of the eyes t o the m i d l i n e of head.  Thorax: pronotum  w i t h 18 b r i s t l e s on the v e n t r a l t h i r d ; d o r s o - c e n t r a l  bristles  i n a s i n g l e row p o s t e r i o r l y and s c a t t e r e d randomly a n t e r i orly;  s u p r a - a l a r b r i s t l e s 30; a n t e r o - l a t e r a l b r i s t l e s  p r e s c u t e l l a r b r i s t l e s 5 and p o s t - a l a r b r i s t l e s 3; m e d i a l l y w i t h many s c a t t e r e d b r i s t l e s and t r a n s v e r s e row of 11 b r i s t l e s . produced 0.14  mm.  26;  scutellum  l a t e r a l l y with a  Wing: l e n g t h 3.5  mm.;  C  beyond j u n c t i o n of R 4 5 ; wing membrane +  w i t h numerous m a c r o t r i c h i a and a dark brown p a t c h .  Legs: L.R.  c r o s s - v e i n r-m 0.74;  surrounded by  f o r e t i b i a l s p u r about  as l o n g as w i d t h of t i b i a at apex and w i t h 5 l a t e r a l t e e t h ; fore tarsus without 0.08  mm.  s p u r s 0.1  a b e a r d ; m i d d l e t i b i a l s p u r s 0.095 and  l o n g , each w i t h 5 o r 6 l a t e r a l t e e t h ; h i n d and 0.075 mm.  ( F i g . 4-A);  tibial  l o n g , each w i t h 5 o r 6 l a t e r a l  t e e t h ; p r e a p i c a l comb of t i b i a w i t h 10 s p i n e s . s t y l e without  Hypopygium:  a prominent p o s t e r i o r p r o j e c t i o n  and s t r u t s at base of c o x i t e w i t h o u t d e n t i c l e s .  3  31 P u p a : — l e n g t h 8.1-9.8 mm.(4), e x u v i a d a r k brown. t o r y organ { F i g . 4-C) wide.  0.73-0.82 mm.  Respira-  l o n g and 0.32-0.33  mm.  Abdomen: t e r g i t e I w i t h a median s c a r 0.25-0.30  mm.  l o n g ; t e r g i t e I I t o V I I I u n i f o r m l y shagreened; a n a l l o b e s ( F i g . 4-B)  each w i t h 2 l a t e r a l f i l a m e n t s , 61-75  f i n e marginal  s p i n e s and a caudo-mesal s p u r . Larva:—  y e l l o w i s h brown, maximum l e n g t h 16 mm.  l e n g t h of b a s a l segment 0.22-0.27 mm. 1.25  Antenna:  Head: l e n g t h  1.12-  mm.(6); e y e s p o t s connected and r e n i f o r m ; l i n g u a s i m i l a r  t o t h a t shown i n F i g u r e 3-S, l i n g u a ( F i g . 4-E)  w i t h 2-3  r a r e l y w i t h only 4 t e e t h ; superi n n e r s p i n e s , an a p i c a l and  o u t e r s p i n e s ; p e c t e n w i t h 15-17 comb ( F i g . 4-D) tooth. and 0.09  w i t h 8-10  s p i n e s per s i d e ; p a r a l a b i a l  dark t e e t h and a l i g h t m e d i a l  Abdomen: a n a l p a p i l l a t u b u l a r , about 0.35 mm.  mm.  wide and w i t h 14 a p i c a l b r i s t l e s ; a n a l  p o i n t e d , about 0.55  mm.  4  l o n g and 0.17  mm.  long gills  wide a t base.  E c o l o g y : — T h i s i s a r a r e s p e c i e s i n Marion Lake.  Larvae  were c o l l e c t e d at depths of 4-6  adult  metres and  emergence took p l a c e d u r i n g A p r i l and  May.  M a t e r i a l e x a m i n e d : — lo", 11.V.64; 2 pup., exuv., 18.V.64; 1 pup.  i n 1964  ?.V.64; 1  pup.  exuv., 7.V.64; 3 l a r v . , 12.11.64; 3  l a r v . , 15.IV. 64, Marion Lake,  B.C.  32 Genus PSECTROTANYPUS K i e f f e r P s e c t r o t a n y p u s K i e f f e r , 1909,  B u l l . Soc. Nat. H i s t . Metz.  26:43 P s e c t r o t a n y p u s F i t t k a u , 1962, Akaderaie-Verlag, B e r l i n ,  pp.  129-133 One  s p e c i e s i s known to o c c u r i n Marion Lake.  Psectrotanypus v a r i u s ( F a b r i c i u s ) Chironomus v a r i u s F a b r i c i u s , 1787, p. 325, Psectrotanypus  Mantissa  Insectorium  45  v a r i u s F i t t k a u , 1962, A k a d e m i e - V e r l a g , B e r l i n ,  pp.  134-140  The  a d u l t male and p u p a l e x u v i a examined appear t o  be i d e n t i c a l w i t h the European s p e c i e s P. v a r i u s .  The  t i o n and pigment p a t t e r n s o f the wing are remarkably t o t h a t i l l u s t r a t e d by F i t t k a u (1962).  vena-  similar  S u b l e t t e (1964) does  not l i s t P. v a r i u s as a s p e c i e s o c c u r r i n g i n North  America.  The specimen from Marion Lake keys t o c o u p l e t 11 i n h i s key, but has two brown bands on the t i b i a u n l i k e A.  guttalaris  ( C o q u i l l e t ) and has a l o n g e r t a r s a l beard than A.  venusta  (Coquillet). Male i m a g o : — t h o r a x head and antenna b l a c k i s h brown; abdomen brown w i t h a n t e r i o r p a r t of t e r g i t e s much d a r k e r ;  33 l e g s brown w i t h dark r i n g s as f o l l o w s , femur and t i b i a each w i t h a b a s a l and an a p i c a l band, t a r s u s 1, 2 and 3 near a p i c e s , t e r m i n a l segments a l l d a r k . 2 . 3 3 ( 1 ) , f l a g e l l u m w i t h 14 segments.  darker  Antenna:  Head: p a l p  A.R.  proportions  9:18:22:25; c l y p e u s w i t h 21 b r i s t l e s ; t e m p o r a l h a i r s p o s t e r i o r l y i n d o u b l e rows which n e a r l y meet a t the m i d l i n e of head.  Thorax: pronotum w i t h 24 h a i r s ; d o r s o - c e n t r a l b r i s t l e s  s c a t t e r e d , about 48 i n number; a n t e r o - l a t e r a l b r i s t l e s  6;  s u p r a - a l a r b r i s t l e s s c a t t e r e d , about 50 i n number; p o s t - a l a r b r i s t l e s 6; p r e s c u t e l l a r b r i s t l e s 3; s c u t e l l u m w i t h a s i n g l e t r a n s v e r s e row of b r i s t l e s except i n the median area where t h e r e i s an a d d i t i o n a l t r a n s v e r s e row.  Wing: l e n g t h 3.5  mm.;  a r c u l u s d a r k and squama w i t h a d a r k spot near j u n c t i o n w i t h a l u l a ; wing membrane w i t h d a r k p a t c h e s around c r o s s - v e i n s m-cu  and r-m  and between C and R4+5J m a c r o t r i c h i a numerous;  c r o s s - v e i n r-m vein  m-cu.  o b l i q u e and about 3 times as l o n g as c r o s s -  Legs: L.R.  0.65;  f o r e t i b i a l s p u r 7/8  as  long  as w i d t h o f t i b i a a t apex and w i t h at l e a s t 15 s h o r t , b l u n t , l a t e r a l t e e t h ; p r e a p i c a l comb of f o r e t i b i a w i t h 4 l o n g s p i n e s ; t a r s a l beard p r e s e n t , l o n g e r b r i s t l e s 5-6  times  as  l o n g as d i a m e t e r of t a r s u s ; m i d d l e t i b i a l s p u r s 0.095 and 0.09  mm.  l o n g , w i t h 18 and  middle t i b i a without 0.09  and 0.08  mm.  14 l a t e r a l t e e t h r e s p e c t i v e l y ;  a p r e a p i c a l comb; h i n d t i b i a l  l o n g , w i t h 17 and  spurs  16 l a t e r a l t e e t h  t i v e l y ; p r e a p i c a l comb of h i n d t i b i a w i t h 9 s p i n e s ;  respecpulvilli  34 p r e s e n t and about h a l f as l o n g as c l a w s .  Hypopygium: ( F i g .  4-F) s t y l e s t r a i g h t w i t h an e n l a r g e d base. P u p a : — l e n g t h about 7.0 mm.  (abdominal  segments I - I V mis-  s i n g ) , e x u v i a brown, t e r g i t e s d a r k e r near t h e median l i n e . R e s p i r a t o r y organ: 0.2 mm. wide.  ( F i g . 4-H) s p i n o u s , 0.68 mm. l o n g and  Abdomen: t e r g i t e s v e r y f i n e l y shagreened;  t e r g i t e s V I I and V I I I w i t h 6 and 5 l a t e r a l b r i s t l e s r e s p e c t i v e l y ; a n a l f i n ( F i g . 4-G) 1.05 times as l o n g as wide, each l o b e w i t h about 55 l a t e r a l h a i r s and about 29 i n n e r ones. Ecology:—  The o n l y specimens o b t a i n e d were an a d u l t and a  p u p a l e x u v i a c o l l e c t e d i n an emergence t r a p on October 11, 1964. M a t e r i a l e x a m i n e d : — 1°", 11.X.64; 1 pup. exuv., 11.X.64, Marion L a k e , B.C.  T r i b e COELOTANYPODINI Genus CLINOTANYPUS K i e f f e r C l i n o t a n y p u s K i e f f e r , 1913, Rec. I n d i a n Mus. 9:157 C l i n o t a n y p u s Edwards, 1929, T r a n s , e n t . Soc. Lond. 77:302 One s p e c i e s i s known t o o c c u r i n Marion Lake.  35 Clinotanypus sp. A T h i s s p e c i e s was not r e a r e d and o n l y l a r v a e and a s i n g l e female pupa a r e a v a i l a b l e .  The pupa and l a r v a b o t h  key t o C. t h o r a c i c u s (Loew), i n Roback (1957) but t h e M a r i o n Lake s p e c i e s i s l a r g e r and has about 4 t i m e s as many p o i n t s on t h e l a r v a l p e c t e n . P u p a : — l e n g t h 11.0 mm.  R e s p i r a t o r y organ: ( F i g . 4 - J ) ;  about 3 times as l o n g as broad and covered w i t h s p i n u l e s . Abdomen: t e r g i t e s u n i f o r m l y shagreened; t e r g i t e s I-VI appare n t l y w i t h o u t l a t e r a l b r i s t l e s o r s p i n e s ; segment V I I w i t h 5-7 l a r g e l a t e r a l b r i s t l e s  (specimen d e s c r i b e d had 5 b r i s -  t l e s on one s i d e and 7 on t h e o t h e r ) ; t e r g i t e V I I I w i t h 5 l o n g b r i s t l e s ; a n a l f i n ( F i g . 4-1) about 1.1 times as wide as l o n g , each l o b e f r i n g e d w i t h more than 160 f i n e h a i r s . Larva:—  r e d d i s h o r brownish,, maximum l e n g t h 14 mm.  Anten-  na: ( F i g . 4-K);.A.R. 1 3 - 1 4 ( 2 ) , u s u a l l y p r o j e c t i n g i n p r e s e r ved l a r g a e , b a s a l segment 0.78-0.85 mm. l o n g , s e n s o r i u m about 0.08 mm. from apex.  Head: l e n g t h 1.24-1.28 mm.; e y e -  s p o t s c o n t i g u o u s and r e n i f o r m ; m a x i l l a r y p a l p u s w i t h a s i n g l e b a s a l segment which i s about 4.5 times as l o n g as g r e a t e s t w i d t h ; mandible ( F i g . 4-M) hook shaped w i t h a d a r k p o i n t e d a p i c a l t o o t h , about 5 s m a l l b l u n t l a t e r a l s  and a  v e r y prominent a c c e s s o r y t o o t h ; l i n g u a ( F i g . 4-L) w i t h 6 p a l e t e e t h and s u p e r l i n g u a  ( F i g . 4-L) w i t h a l o n g a p i c a l  36 which may be notched on e i t h e r s i d e ; p e c t e n w i t h 33-36 short spines per s i d e .  Abdomen: w i t h a dense row o f h a i r s  on e i t h e r s i d e o f body; a n a l p a p i l l a about 2.5 t i m e s as l o n g as broad and w i t h 14 o r 15 t e r m i n a l b r i s t l e s ; i o r p r o l e g s w i t h about 16 u n i f o r m l y c o l o u r e d  poster-  claws.  E c o l o g y : — T h i s i s a r a r e s p e c i e s i n M a r i o n Lake.  Larvae  were c o l l e c t e d a t depths from 0.5-1.5 metres and the pupa was c o l l e c t e d J u l y 29, 1964 i n an emergence t r a p s e t o v e r a d e p t h o f one metre. M a t e r i a l examined:— lo"pup., 29.VII.64; 1 l a r v . ,  7.VII.63;  1 l a r v . , 22.VII.64, M a r i o n L a k e , B.C.  T r i b e PENTANEURINI Genus THIENEMANNIMYIA F i t t k a u Thienemannimyia  F i t t k a u , 1957, A r c h . H y d r o b i o l . 53:313-322.  Thienemannimyia  F i t t k a u , 1962, Akademie-Verlag, B e r l i n , pp.  164-174, One s p e c i e s i s known t o o c c u r i n M a r i o n Lake.  Thienemannimyia  sp. A  T h i s s p e c i e s i s c l o s e t o T. f u s c i c e p s (Edwards), a European s p e c i e s ; however, t h e a d u l t male has a narrower  37 s t y l e than t h a t o f T. f u s c i c e p s and t h e p u p a l r e s p i r a t o r y organ i s not spinous fusciceps.  as i s t h e case w i t h t h e pupa o f T.  The n e a r e s t d e s c r i b e d North American s p e c i e s  appears t o be T. norena (Roback). Male i m a g o : — b r o w n i s h , a n t e r i o r p a r t s o f t e r g i t e s  III-VIII  b r o w n i s h b l a c k , l e g s u n i f o r m l y brown, h a l t e r e s w h i t e . Antenna: A.R. 2 0 5 ( 1 ) , f l a g e l l u m w i t h 14 segments.  Head:  p a l p p r o p o r t i o n s 11:17:20:23; c l y p e u s w i t h 15 b r i s t l e s ; temp o r a l h a i r s i n s i n g l e rows which n e a r l y meet a t m i d l i n e o f head.  Thorax: pronotum w i t h about 6 f i n e b r i s t l e s ;  dorso-  c e n t r a l and s u p r a - a l a r b r i s t l e s i n s i n g l e i r r e g u l a r rows; p o s t - a l a r b r i s t l e s 2; s c u t e l l u m w i t h 2 t r a n s v e r s e rows o f b r i s t l e s and a few a d d i t i o n a l s c a t t e r e d b r i s t l e s near t h e midline.  Wing l e n g t h 2.7 mm.,  l i g h t c o l o u r e d except f o r an  a r e a around t h e c r o s s - v e i n r-m and a second area above Cu; wing membrane w i t h numerous m a c r o t r i c h i a ; a r c u l u s l i g h t and squama w i t h a d a r k spot near j u n c t i o n o f a l u l a . 0.77;  Legs: L.R.  f o r e t i b i a l s p u r about 3/4 as l o n g as w i d t h o f t i b i a  a t apex and w i t h 6 l a t e r a l t e e t h ; t a r s u s w i t h a d i s t i n c t b e a r d , t h e l o n g e r h a i r s about 4 times as l o n g as d i a m e t e r of t a r s u s ; middle t i b i a l s p u r s 0.07 and 0.05 mm. l o n g , each w i t h 5 o r 6 l a t e r a l t e e t h ; p r e a p i c a l comb o f h i n d t i b i a w i t h 7 spines.  Hypopygium: ( F i g . 5-A) s t y l e much e n l a r g e d a t  base; base o f c o x i t e w i t h a d i s t i n c t i v e , s p i n o u s , i n n e r l o b e .  38 P u p a : — l e n g t h 6.1  mm.,  exuvia uniformly brownish.  a t o r y organ: ( F i g . 5-B);  0.25  mm.  Respir-  l o n g , l i g h t i n c o l o r and  s h a r p l y bent near attachment t o body, r e s p i r a t o r y chamber convaluted  and w i t h o u t  a sieve plate.  Abdomen: t e r g i t e s  and p l e u r a u n i f o r m l y covered w i t h minute s p i n u l e s , i n t e g u ments between t e r g i t e s and p l e u r a b a r e ; l a t e r a l f i l a m e n t s on segments I I - V I I I 6-6-6-6-6-5-5.  A n a l f i n ( F i g . 5-C)  t i m e s as l o n g as wide, lobes of a n a l f i n w i t h o u t  1.09  marginal  spinules. E c o l o g y : — This i s a r a r e species i n Marion Lake.  The  larva  i s unknown and the a d u l t and p u p a l e x u v i a were c o l l e c t e d June 27,  1964  i n an emergence t r a p .  M a t e r i a l e x a m i n e d : — lo", 27.VI.64; 1 pup. Marion Lake,  exuv., 27.VI.64,  B.C.  Genus ZAVRELIMYIA F i t t k a u Z a v r e l i m y i a F i t t k a u , 1962,  Akademie-Verlag, B e r l i n , pp.  285-  294 At l e a s t one  and p r o b a b l y  two  species occur i n  Marion Lake.  Z a v r e l i m y i a sp. A S p e c i f i c i d e n t i f i c a t i o n of the one  adult a v a i l a b l e  39 was  not d e t e r m i n e d .  Male i m a g o : — t h o r a x and  antenna d a r k brown; abdomen w h i t i s h  w i t h d a r k m a r k i n g s , p a r t i c u l a r l y on the p o s t e r i o r t e r g i t e s , l e g s u n i f o r m l y brown. 14 segments.  Antenna: A.R.  2.0(1), f l a g e l l u m w i t h  Head: p a l p p r o p o r t i o n s 12:18:18:27; c l y p e u s  w i t h 18 b r i s t l e s ; t e m p o r a l h a i r s i n s i n g l e rows which n e a r l y meet at the m i d l i n e of head.  Thorax: pronotum w i t h 5 f i n e  b r i s t l e s ; d o r s o - c e n t r a l b r i s t l e s 28 i n a s i n g l e row; a l a r b r i s t l e s 13 o r 14 i n a d o u b l e i r r e g u l a r row; post-alar  b r i s t l e and 2 p r e s c u t e l l a r b r i s t l e s ;  w i t h 2 t r a n s v e r s e rows of b r i s t l e s .  supra-  one scutellum  Wing: l e n g t h 2.8  mm.;  a r c u l u s y e l l o w i s h ; squama w i t h a dark brown s p o t ; wing membrane l i g h t c o l o r e d and w i t h numerous m a c r o t r i c h i a . L.R.  0.70;  f o r e t i b i a l s p u r ( F i g . 5-E)  about 3/4  Legs:  as l o n g  as  w i d t h of t i b i a at apex, l y r e shaped w i t h 9 p o i n t e d t e e t h ; m i d d l e t i b i a l s p u r s 0.05  and 0.04  mm.  p o i n t e d t e e t h ; h i n d t i b i a l s p u r s 0.09  long, w i t h 5 to 7 long and 0.04  p r e a p i c a l comb of h i n d t i b i a w i t h 7 s p i n e s . (Fig.  5-D);  Ecology:—  mm.  long;  Hypopygium:  s t y l e l o n g and narrow w i t h a l o n g a p i c a l s p i n e . The o n l y specimen c o l l e c t e d was  t a k e n June 10, 1965  an a d u l t male  a l o n g the shore of Marion L a k e .  M a t e r i a l e x a m i n e d : — lo", 10.VI. 65, M a r i o n L a k e ,  B.C.  40 Z a v r e l i m y i a sp. B S p e c i f i c i d e n t i f i c a t i o n of t h i s s p e c i e s was  not  attempted. Male i m a g o : — head, antenna and  t h o r a x brown, l e g s u n i f o r m l y  l i g h t brown and abdominal t e r g i t e s I I - V I I d a r k e r on ior halves. segments. 21-27  Antenna: A.R.  anter-  1.88-2.20(2), f l a g e l l u m w i t h  14  Head: p a l p p r o p o r t i o n s 13:17:18:29; c l y p e u s w i t h  b r i s t l e s ; t e m p o r a l h a i r s i n s i n g l e rows which n e a r l y  meet at the m i d l i n e of head.  Thorax: pronotum w i t h 6  b r i s t l e s ; d o r s o - c e n t r a l b r i s t l e s , about 26 i n a d o u b l e i r r e g u l a r row;  s u p r a - a l a r b r i s t l e s 13, one p o s t - a l a r b r i s -  t l e ; s c u t e l l u m w i t h a t r a n s v e r s e row of l a r g e b r i s t l e s near the p o s t e r i o r margin and a s h o r t e r a n t e r i o r row of s m a l l e r bristles.  Wing: l e n g t h 2.5,-2.8 mm.;  a r c u l u s dark  and  squama w i t h a d a r k s p o t near j u n c t i o n w i t h a l u l a ; wing membrane l i g h t c o l o r e d and w i t h numerous m a c r o t r i c h i a . L.R.  Legs:  0.74(1) f o r e t i b i a l s p u r l y r e shaped, w i t h at l e a s t 7  p o i n t e d t e e t h ; f o r e t a r s u s w i t h a b e a r d , the l o n g e r h a i r s 4 t i m e s as l o n g as w i d t h of t a r s u s ; m i d d l e t i b i a l s p u r s and 0.03  mm.  l o n g , each w i t h 4 o r ,5 p o i n t e d t e e t h ; h i n d  t i b i a l s p u r s 0.075 and 0.04 t i b i a with 4 or 5 spines. about 2/3  0.05  mm.  l o n g ; p r e a p i c a l comb of h i n d  Hypopygium: ( F i g . 5-F);  style  as l o n g as c o x i t e and w i t h a b l u n t t e r m i n a l s p i n e .  E c o l o g y : — A d u l t s were c o l l e c t e d a l o n g the shore of M a r i o n  41 Lake d u r i n g May,  1965.  M a t e r i a l examined:—  lo", 8.V.65; lo", 25.V.65, M a r i o n Lake,  B.C.  Z a v r e l i m y i a sp. C The o n l y known specimen of t h i s s p e c i e s i s a p u p a l e x u v i a c o l l e c t e d June 10, 1965 on the s u r f a c e of Marion Lake.  S p e c i f i c determination  was not attempted but the d a t e  of c o l l e c t i o n s u g g e s t s t h a t t h i s i s the pupa of Z s p . A. However, i t i s p o s s i b l e t h a t t h i s pupa i s t h a t of Z sp. B. Pupa:—  l e n g t h 5.8 mm.,  e x u v i a u n i f o r m l y l i g h t brown.  Res-  p i r a t o r y organ: ( F i g . 5-G); r e s p i r a t o r y f u n n e l c i r c u l a r and much c o n s t r i c t e d at base.  Abdomen: t e r g i t e s not shagreened;  t e r g i t e s I-VI w i t h o u t l a t e r a l f i l a m e n t s o r h a i r s ; t e r g i t e s V I I and V I I I w i t h 4 o r 5 p a i r s o f l a t e r a l f i l a m e n t s r e s p e c t i v e l y ; a n a l f i n ( F i g . 5-H)  1.36  t i m e s as l o n g as b r o a d ,  each lobe w i t h 2 v e r y wide l a t e r a l f i l a m e n t s , about 24 l a t e r a l s p i n u l e s and about 9 i n n e r s p i n u l e s . M a t e r i a l examined:—  1 pup. exuv., 10.VI.65, Marion Lake,  B.C.  Genus LARSIA F i t t k a u L a r s i a F i t t k a u , 1962, A k a d e m i e - V e r l a g , B e r l i n , pp. 339-346,,  42 One  s p e c i e s i s known to o c c u r i n M a r i o n Lake.  L a r s i a a c r o c i n c t a (Goetghebuer) A b l a b e s m y i a a c r o c i n c t a Goetghebuer, 1942,  B u l l . Mus.  r. Hist,  n a t . B e l g . 76:9-10 L a r s i a a c r o c i n c t a F i t t k a u , 1962,  Akademie-Verlag, B e r l i n ,  pp. 347-349 T h i s s p e c i e s was tentatively associated.  not r e a r e d and the l a r v a i s o n l y  The  specimens from M a r i o n Lake are  p r o b a b l y L. a c r o c i n c t a , a r a t h e r v a r i a b l e s p e c i e s t h a t i s wide spread  i n Europe.  T h e - t i p of the s t y l e of the a d u l t  male i s somewhat curved whereas i n F i t t k a u ' s d i a g r a m the s t y l e i s almost s t r a i g h t .  O t h e r c h a r a c t e r i s t i c s of  a d u l t male and the pupa agree w e l l w i t h those of  the  L.  acrocincta. Male i m a g o : — t h o r a x y e l l o w , abdomen w h i t i s h w i t h f a i n t brown bands and  l e g s u n i f o r m l y l i g h t brown.  1.44(1), f l a g e l l u m w i t h 14 segments.  Head:  Antenna:  A.R.  palp,propor-  t i o n s 7:8:11:15; c l y p e u s w i t h 15 b r i s t l e s ; d o r s o - c e n t r a l b r i s t l e s 21 i n a s i n g l e row except at a n t e r i o r end where they are s c a t t e r e d ; s u p r a - a l a r b r i s t l e s 9 i n a d o u b l e i r r e g u l a r row;  one p o s t - a l a r b r i s t l e and 3 p r e s c u t e l l a r  b r i s t l e s ; s c u t e l l u m w i t h 2 t r a n s v e r s e rows of b r i s t l e s ,  the  43 p o s t e r i o r row c o n s i s t s of much the c o a r s e r b r i s t l e s . l e n g t h 1.65  mm.;  Wing:  a r c u l u s l i g h t and squama w i t h a d i s t i n c t  brown spot about h a l f way  a l o n g o u t e r margin; wing membrane  h a i r y and u n i f o r m l y c o l o r e d .  Legs: L.R.  0.72;  fore  tibial  s p u r l y r e shaped w i t h 9 o r 10 p o i n t e d t e e t h ; t a r s u s w i t h a short beard; middle t i b i a l spurs  l y r e shaped, each w i t h 8  t e e t h ; h i n d t i b i a l s p u r s l y r e shaped each w i t h 8 o r 9 t e e t h (Fig.  6-B) ;, p r e a p i c a l comb of h i n d t i b i a w i t h 7 s p i n e s ( F i g .  6-B).  Hypopygium: ( F i g . 6-A);  s t y l e l o n g and narrow w i t h a  long terminal spine. P u p a : — l e n g t h 3.6  mm.(l), e x u v i a y e l l o w i s h w i t h prominent  d a r k brown markings a l o n g the a n t e r i o r h a l f of each abdominal tergite 0.23  mm.,  ( F i g . 6-C). covered  R e s p i r a t o r y organ: ( F i g . 6-D)  with spinules.  Cephalothorax:  length w i t h about  13 b l u n t s p i n e s near the base of each r e s p i r a t o r y o r g a n . Abdomen: t e r g i t e s w i t h minute s p i n u l e s p l a c e d i n s h o r t t r a n s v e r s e rows; segments I-VI w i t h o u t  l a t e r a l h a i r s or f i l a m e n t s ;  segments V I I and V I I I w i t h 4 o r 5 p a i r s of l a t e r a l f i l a m e n t s r e s p e c t i v e l y ; a n a l f i n ( F i g . 6-E)  1.83  times as l o n g as wide,  each l o b e w i t h about 14 l a t e r a l s p i n u l e s and no i n n e r s p i n u l e s ; l a t e r a l f i l a m e n t s of a n a l l o b e s v e r y broad Larva:—  greenish.  apically.  Antenna ( F i g . 6-F):.A.R. 4.1-4.3(2),  b a s a l segment 0.22-0.24 mm.  l o n g , s e n s o r i u m 0.54-0.57 of  d i s t a n c e t o the apex of segment I .  the  Head: l e n g t h 0.53-0.58  44  mm.,  somewhat r e c t a n g u l a r i n shape ( F i g . 6-G);  ( F i g . 6-G)  eyespots  c o n t i g u o u s and r e n i f o r m ; m a x i l l a r y p a l p u s w i t h a  s i n g l e b a s a l segment, about 3 times as l o n g as b r o a d ; mandib l e ( F i g . 6-1)  w i t h a broad a p i c a l , 2 s m a l l l a t e r a l s and a  t h i r d l a r g e r l a t e r a l ; l i n g u a ( F i g . 6-H)  w i t h 5 t e e t h ; super-  l i n g u a b i f i d and p e c t e n w i t h 12 o r 13 t e e t h p e r s i d e . Abdomen: a n a l p a p i l l a about 4 t i m e s as l o n g as broad and w i t h 7 a p i c a l b r i s t l e s ; a n a l g i l l s l o n g , narrow and t a p e r i n g t o a point;, p o s t e r i o r p r o l e g s w i t h t e r m i n a l claws a l l of the same color. E c o l o g y : — T h i s i s a r a r e s p e c i e s i n M a r i o n Lake.  In  1964  a d u l t s and p u p a l e x u v i a e were c o l l e c t e d i n emergence t r a p s s e t o v e r depths of l e s s than 1.0 metres d u r i n g August, September and e a r l y O c t o b e r . M a t e r i a l examined:—  lo", 1 9 . y i I I . 6 4 ; 1 pup. exuv., 19. V I I I .  64; 2 l a r v . , 7.VII.64, M a r i o n Lake,  Genus ABLABESMYIA Ablabesmyia Johannsen,  B.C.  Johannsen  1905, B u l l . N.Y.  S t . Mus.  86:135  A b l a b e s m y i a F i t t k a u , 1962, Akademie-Verlag, B e r l i n , pp.  416-  429 At l e a s t one s p e c i e s o c c u r s i n Marion Lake.  Some  of the l a r v a e f o r which the genus c o u l d not be d e t e r m i n e d  45 may  a l s o belong  t o t h i s genus.  Ablabesmyia m o n i l i s T i p u l a monilus Linnaeus,  1758,  (Linnaeus)  S y s t . Nat. Ed. X. p.  P e n t a n e u r a (Ablabesmyia) m o n i l i s Roback, 1959, e n t . Soc.  Trans.  Am.  85:128-130  A b l a b e s m y i a m o n i l i s F i t t k a u , 1962, pp.  587  Akademie-Verlag, B e r l i n .  437-440  T h i s s p e c i e s was  reared.  A l l the l i f e  stages  agree w e l l w i t h the p u b l i s h e d d e s c r i p t i o n s of A.  monilis  and the a d u l t male keys t o A. m o n i l i s i n Roback  (1959).  T h i s s p e c i e s i s widespread throughout Europe and  North  America. Male i m a g o : — t h o r a x , head and abdomen b l a c k i s h brown, segments VI and V I I n e a r l y b l a c k , h a l t e r e s w h i t e ;  legs  l i g h t brown w i t h d a r k brown bands; femur w i t h a s i n g l e a p i c a l b a n d , . t i b i a w i t h an a p i c a l , a d i s t a l and a c e n t r a l band, b a s a l segment of t a r s u s w i t h two bands and the remaini n g segments e n t i r e l y d a r k brown o r w i t h a s i n g l e band. Antenna: A.R.  2.1-2.2(2), f l a g e l l u m w i t h 14 segments.  Head:  p a l p p r o p o r t i o n s 12:20:14:26; c l y p e u s w i t h 32-39 b r i s t l e s ; t e m p o r a l h a i r s randomly p l a c e d and v e r y numerous, p a r t i c u l a r l y between v e r t e x a n g l e s of eye and the m i d l i n e of head. Thorax: pronotum w i t h 15 o r 16 f i n e h a i r s ; d o r s o - c e n t r a l  46 b r i s t l e s i n a s i n g l e row which i s c o n t i n u o u s c u t e l l a r b r i s t l e s ; s u p r a - a l a r b r i s t l e s mostly  w i t h the p r e s i n a single  i r r e g u l a r row; one p o s t - a l a r b r i s t l e ; s c u t e l l u m w i t h two i r r e g u l a r rows o f b r i s t l e s near t h e l a t e r a l margin and media l l y with scattered b r i s t l e s . 2.6-2.7 mm.;  Wing: ( F i g . 21-B); l e n g t h  wing membrane w i t h brown markings and numerous  m a c r o t r i c h i a which a r e brown i n pigmented a r e a s and c o l o r l e s s i n o t h e r a r e a s ; a r c u l u s d a r k and squama w i t h a d a r k spot near j u n c t i o n w i t h a l u l a .  Legs: L.R. 0.78-0.85; f o r e  t i b i a l s p u r about as l o n g as w i d t h o f t i b i a a t apex; f o r e tarsus without mm.  a b e a r d ; middle t i b i a l s p u r s 0.07 and 0.04  l o n g ; h i n d t i b i a l s p u r s 0.07 and 0.04 mm. l o n g , each w i t h  about 8 l a t e r a l t e e t h ; p r e a p i c a l comb o f h i n d t i b i a absent. Hypopygium: ( F i g . 6 - J ) ; s t y l e l o n g and narrow, a p i c a l l y w i t h two p r o j e c t i o n s , t h e l a r g e r one dark and spoon shaped. P u p a : — l e n g t h 5.3-5.8 mm.(6), e x u v i a y e l l o w i s h w i t h brown m a r k i n g s , p a r t i c u l a r l y a l o n g c a u d a l margins o f abdominal tergites.  R e s p i r a t o r y organ: ( F i g . 6-K); d a r k brown and  f i n e l y r e t i c u l a t e , about 1.5 times as l o n g as broad and w i t h out a s i e v e p l a t e .  Abdomen: t e r g i t e s v e r y f i n e l y shagreened;  t e r g i t e s I-VI w i t h o u t  l a t e r a l hairs or b r i s t l e s ; tergites VII  and V I I I w i t h 4 and 5 p a i r s o f l a t e r a l b r i s t l e s r e s p e c t i v e l y ; a n a l f i n ( F i g . 6-L) about 1.25 times as l o n g as b r o a d , and each lobe w i t h about 25 f i n e s p i n u l e s on l a t e r a l margin and none on i n n e r m a r g i n . Larva:—  y e l l o w , w i t h prominent brown m a r k i n g s .  Antenna:  47 A. R. 5.2-5.5(4), b a s a l segment 0.40-0.48 mm.  long, sensorium  0.56-0.6 o f the d i s t a n c e t o the apex o f segment I . l e n g t h 0.94-1.06 mm.,  e y e s p o t s c o n t i g u o u s and r e n i f o r m ; max-  i l l a r y p a l p u s ( F i g . 6-N) (Fig.  Head:  w i t h 2 b a s a l segments;  mandible  6-0) w i t h a l o n g p o i n t e d a p i c a l t o o t h and 3 l a t e r a l  t e e t h ; l i n g u a ( F i g . 6-M)  with 5 teeth; superlingua b i f i d  p e c t e n w i t h 14 o r 15 s p i n e s p e r s i d e .  and  Abdomen: a n a l p a p i l l a  about 3 times as l o n g as broad and w i t h 7 a p i c a l  bristles;  a n a l g i l l s l o n g , s l e n d e r and t a p e r i n g to a p o i n t ; p o s t e r i o r p r o l e g s w i t h 2 ( o c c a s i o n a l l y 1) s h o r t , dark c l a w s ( F i g . 6-P) i n a d d i t i o n to the numerous l o n g l i g h t c o l o r e d E c o l o g y : — T h i s s p e c i e s i s abundant  claws.  i n M a r i o n Lake.  l a r v a e o c c u r r e d f r e q u e n t l y at a l l depths and i n 1964  Benthic adult  emergence l a s t e d from the second week i n June u n t i l the middle  of October.  M a t e r i a l examined:-^-  l c f , 15.VI1.64;  l o " , 10.VI.65; 3 pup.  exuv., 15.VII.64; 2 pup. exuv., 22.VII.64; 1 pup. exuv.,  10.  V I I I . 6 4 ; 2 l a r v . , 22.VII.64; 2 l a r v . , 8 . V I I I . 6 4 , M a r i o n Lake, B. C.  P e n t a n e u r i n i sp. A T h i s s p e c i e s i s d e s c r i b e d o n l y from l a r v a e .  They  key t o Pentaneura b a s a l i s ( W a l l e y ) i n Roback (1957), but pupae and a d u l t s of P. b a s a l i s (^Ablabesmyia b a s a l i s ) a r e not known t o o c c u r i n o r around M a r i o n Lake.  48 Larva:— A.R.  body l i g h t c o l o r e d , l e n g t h about 7.0 mm.  5.0-5.7(3), b a s a l segment 0.46-0.48 mm.  long, sensorium  0.57-0.61 of the d i s t a n c e t o t h e apex of f i r s t Head: l e n g t h 0.98-1.13 mm.;  Antenna:  segment.  e y e s p o t s j o i n e d and r e n i f o r m ;  m a x i l l a r y p a l p u s ( F i g . 5-J) w i t h 6 b a s a l segments; mandible w i t h a l o n g p o i n t e d a p i c a l and 2 l a t e r a l t e e t h ; l i n g u a ( F i g . 5-1) w i t h 5 dark t e e t h ; s u p e r l i n g u a b i f i d and p e c t e n w i t h 15 o r 16 s p i n e s p e r s i d e .  Abdomen: a n a l p a p i l l a about 3 t i m e s  as l o n g as broad and w i t h 7 a p i c a l b r i s t l e s ; a n a l  gills  l o n g and t a p e r i n g t o a p o i n t ; p o s t e r i o r p r o l e g s each w i t h one a d d i t i o n a l d a r k e r , h o o k - l i k e c l a w . E c o l o g y : — The specimens examined were a l l c o l l e c t e d a t a depth o f 0.05 metres on June 10, 1964. M a t e r i a l examined:—  3 l a r v . , 10.VI.64, M a r i o n L a k e ,  B.C.  P e n t a n e u r i n i sp. B T h i s l a r v a c o u l d not be i d e n t i f i e d t o the g e n e r i c l e v e l , but i t keys t o c o u p l e t 17 i n Roback  (1957) and one of  the s p e c i e s i n c l u d e d t h e r e i s P. t e t r a s t i c a ?  (Kieffer).  F i t t k a n p l a c e s t h i s s p e c i e s i n the genus Z a v r e l i m y i a so i t i s p o s s i b l e t h a t t h i s i s the l a r v a l form o f e i t h e r Z. s p . A o r Z. s p . B. Larva:— 5-L) A.R.  l i g h t c o l o r e d , l e n g t h about 7 mm.  Antenna: ( F i g .  5.8-7.0(3) b a s a l segments 0.32-0.35 mm.  long,  49 s e n s o r i u m 0.66-0.69 o f t h e d i s t a n c e t o the apex of segment I.  Head: l e n g t h 0.83-0.95 mm.,  e y e s p o t s ( F i g . 5-K) c o n t i g u -  ous and r e n i f o r m ; m a x i l l a r y p a l p u s w i t h a s i n g l e b a s a l segment, about 3 t i m e s as l o n g as g r e a t e s t w i d t h ;  mandible  ( F i g . 5-N) w i t h a b l u n t a p i c a l t o o t h which i s darkened at t i p , 1 o r 2 minute l a t e r a l s and a narrow a c c e s s o r y t o o t h ; l i n g u a ( F i g . 5-M) w i t h 5 t e e t h ; s u p e r l i n g u a b i f i d and p e c t e n w i t h 22-26 t e e t h p e r s i d e .  Abdomen: a n a l p a p i l l a  about  t w i c e as l o n g as g r e a t e s t w i d t h , a p i c a l l y w i t h 7 b r i s t l e s ; a n a l g i l l s l o n g , narrow and t a p e r i n g t o a p o i n t ; p o s t e r i o r p r o l e g s w i t h claws a l l o f t h e same c o l o r . E c o l o g y : — B e n t h i c l a r v a e were c o l l e c t e d a t depths r a n g i n g from 0.5-3.5 metres.  I n 1964 no l a r v a e were c o l l e c t e d  after  June 10. M a t e r i a l examined:—  2 l a r v . , 13.V.64; 1 l a r v . ,  10.VI.64,  M a r i o n L a k e , B.C.  P e n t a n e u r i n i sp. C Only t h e l a r v a o f t h i s s p e c i e s i s known.  I t keys  to c o u p l e t 11 i n Roback, 1956 and i s c l o s e t o P. p e l e e n s i s ( W a l l e y ) , a s p e c i e s p l a c e d i n Ablabesmyia by F i t t k a u (1962). Larva:—  light colored.  segment 0.64 mm.  Antenna: A.R. 0 . 5 8 ( 1 ) , b a s a l  l o n g , s e n s o r i u m a t the m i d d l e o f segment I .  Head: l e n g t h 1.18 mm;  e y e s p o t s j o i n e d and r e n i f o r m ;  50 m a x i l l a r y palpus  ( F i g . 6-Q) w i t h 2 b a s a l segments; mandible  ( F i g . 6-R) w i t h a l o n g p o i n t e d a p i c a l t o o t h , 2 l a t e r a l s and a long accessory  tooth; l i n g u a very s i m i l a r to that i n  F i g u r e 5-1; s u p e r l i n g u a b i f i d and p e c t e n w i t h 18 t e e t h p e r side.  Abdomen: a n a l p a p i l l a s l i g h t l y t a p e r e d ,  about t w i c e  as l o n g as w i d t h a t base and w i t h 7 a p i c a l b r i s t l e s ; post e r i o r p r o l e g s each w i t h 2 a d d i t i o n a l dark h o o k - l i k e claws at apex. Ecology:—  The o n l y known l a r v a was c o l l e c t e d A p r i l 29,  1964 a t a depth o f 0.7 metres. M a t e r i a l e x a m i n e d : — 1 l a r v . , 29.IV.64, M a r i o n Lake, B.C.  51 S u b f a m i l y ORTHOCLADINAE B r u n d i n (1956) has i n c l u d e d the former s u b f a m i l y Diamesinae under t h i s s u b f a m i l y . d o i n g t h i s was stages.  H i s c h i e f reason f o r  because o f the s i m i l a r i t y of the immature  A d u l t s are g e n e r a l l y s m a l l to medium i n s i z e .  s t y l e i s movable and t u r n e d inward and the c o x i t e always has an i n n e r l o b e .  The c r o s s - v e i n m-cu  almost  i s present  i n the t r i b e s P r o t a n y p i n i and D i a m e s i n i and absent remaining t r i b e s . always had  The  i n the  The f l a g e l l u m of the male antenna almost  13 segments.  The  l e g r a t i o i s l e s s than 1.0  the f o r e t i b i a has a prominent  spur.  and  The r e s p i r a t o r y organs  of the pupa are s i m p l e and unbranched o r r a r e l y absent.  The  a n a l l o b e s u s u a l l y have 3 o r 4 t e r m i n a l b r i s t l e s and may  or  may  not have m a r g i n a l f i l a m e n t s . The  l a r v a e are w h i t e ,  y e l l o w , green o r r a r e l y r e d and few s p e c i e s are more than 8 mm.  long. T h i s s u b f a m i l y i s r e p r e s e n t e d by at l e a s t  s p e c i e s i n Marion Lake.  15  In a d d i t i o n , two o t h e r s p e c i e s  Prodiamesa sp., and P s e c t r o c l a d i u s sp. have been c o l l e c t e d a l o n g the shore l i n e of the l a k e and p o s s i b l y c o u l d have emerged from i t .  The s p e c i e s i n Marion Lake g e n e r a l l y have  q u i t e wide d i s t r i b u t i o n s w i t h i n the l a k e , and the a d u l t s have r e s t r i c t e d s e a s o n a l p e r i o d s of emergence.  Most of the  s p e c i e s emerge i n s p r i n g o r f a l l and some of them have two generations per year.  52 T r i b e PROTANYPINI Genus PROTANYPUS K i e f f e r P r o t a n y p u s K i e f f e r , 1921, B u l l . Soc. e n t . F r a n c e , pp.  287-  289 P r o t a n y p u s B r u n d i n , 1956, Rep.  I n s t . Freshwat. Res. D r o t -  t n i n g h o l m . 37:60-61 One s p e c i e s i s known t o o c c u r i n M a r i o n Lake.  P r o t a n y p u s sp. A T h i s s p e c i e s was not r e a r e d and o n l y two  larvae  were c o l l e c t e d i n M a r i o n Lake; however, l a r v a e , pupae and a d u l t s were c o l l e c t e d i n Babine Lake, a l a r g e l a k e i n n o r t h c e n t r a l B r i t i s h Columbia.  The l a r v a e from M a r i o n Lake  appear t o be i d e n t i c a l t o those from Babine Lake except t h a t the 5 l a t e r a l t e e t h of the mandible are about t i m e s as l o n g i n the M a r i o n Lake specimens.  1.3  B r u n d i n (1956)  i n h i s r e v i s i o n of the O r t h o c l a d i n a e s t a t e s t h a t t h i s  tribe  o c c u r s from Europe t o Japan, but P. caudatus Edwards has r e c e n t l y been r e p o r t e d from B a f f i n I s l a n d and E l l e s m e r e I s l a n d ( O l i v e r , 1963).  (Oliver,  1964)  A s p e c i e s of  P r o t a n y p u s has a l s o been r e p o r t e d t o o c c u r i n C o s t e l l o Lake, O n t a r i o ( M i l l e r , 1941).  The specimens from B r i t i s h  are c l o s e l y r e l a t e d to P. morio ( Z e t t . ) , a European  Columbia and  S i b e r i a n s p e c i e s , but the c a u d a l p a r t of the c o x i t e of the  53 male imago i s l o n g e r than i n a d u l t s of P. morio. keys to P. morio i n B r u n d i n  The  pupa  (1951) but the a d u l t w i l l  not  key to any of the known European s p e c i e s . Male i m a g o : — a n t e n n a l f l a g e l l u m , m a x i l l a r y p a l p s and u n i f o r m l y d a r k brown; eyes and  antennal p e d i c e l s black;  t h o r a x brownish b l a c k , l i g h t e r i n b r i s t l e p a t c h e s ; brown, d a r k e r near c a u d a l end.  Antenna: A.R.  mean 2 . 9 4 ( 4 ) , f l a g e l l u m w i t h 13 segments. p o r t i o n s 13:19:23:34; c l y p e u s w i t h o u t " hairs  legs  abdomen  2.71-3.23,  Head: P a l p  bristles;  pro-  temporal  numerous, i n an i r r e g u l a r broken band, each band  w i t h one  clump of h a i r s near the mid  second clump under the eyes.  b r i s t l e s s m a l l , 21-40  a  Thorax: pronotum w i t h 25-40  f i n e b r i s t l e s on the v e n t r a l 1/3 e i t h e r s i d e of the mid  l i n e of head and  and 7-11  fine bristles  on  l i n e of t h o r a x ; d o r s o - c e n t r a l mostly  i n a s i n g l e row;  two  antero-  l a t e r a l p a t c h e s of b r i s t l e s , d o r s a l , p a t c h w i t h  15-19  b r i s t l e s and v e n t r a l p a t c h w i t h 25-40 b r i s t l e s ;  supra-alar  bristles  10-17; p o s t - a l a r b r i s t l e s 3-5;  s c u t e l l u m w i t h about  60 s c a t t e r e d b r i s t l e s .  Wing: ( F i g . 21-C)  c r o s s - v e i n m-cu  and about as l o n g as the p a r t of  present  l e n g t h 3.9-4.3  between the f o r k of Cu and the j u n c t i o n of m-cu; the a p i c a l 1/3  of R4+5 w i t h m a c r o t r i c h i a , the  R, R^,  mm., Cu, and  remaining  membrane v e i n s and wing membrane w i t h o u t m a c r o t r i c h i a but w i t h m i c r o t r i c h i a ; a n a l l o b e prominent; squama f r i n g e d and a l u l a w i t h about 7 m a r g i n a l h a i r s . mean 0.66;  Legs: L.R.  f o r e t i b i a l s p u r about 0.12  mm.  long  0.63-0.68, and  54 approximately  as l o n g as w i d t h o f t i b i a a t apex; f o r e t a r s u s  w i t h a b e a r d , the l o n g e s t h a i r s about 6 times as l o n g as t h e d i a m e t e r o f t a r s u s ; m i d d l e t i b i a l s p u r s each about 0.09 mm. l o n g ; h i n d t i b i a l s p u r s about 0.13 and 0.08 mm. l o n g ; p r e a p i c a l comb o f h i n d t i b i a c o n s i s t s o f a dense clump o f s p i n e s ; p u l v i l l i minute.  Abdomen: t e r g i t e s VI and V I I w i t h  6-9 b r i s t l e s on e i t h e r s i d e o f t h e mid l i n e , more a n t e r i o r t e r g i t e s w i t h 18-22 b r i s t l e s grouped a l o n g t h e mid l i n e . Hypopygium: ( F i g . 7-A) c o x i t e extends beyond attachment o f s t y l e by a p p r o x i m a t e l y  the l e n g t h o f t h e s t y l e ; s t y l e w i t h  m i c r o t r i c h i a on p o s t e r i o r s u r f a c e . P u p a : — l e n g t h 8.3-10.6 mm.(4), e x u v i a u n i f o r m l y y e l l o w i s h brown.  R e s p i r a t o r y organ: ( F i g . 7-B) 0.50-0.59 mm.(3)  l o n g , p o i n t e d a p i c a l l y and w i t h o u t  spinules.  Cephalothorax:  w i t h two p a i r s o f t r u n c a t e d t u b e r c l e s on and a d j a c e n t t o the f r o n t a l p l a t e ( F i g . 7-G).  Abdomen: t e r g i t e s I - V I I w i t h  f i n e u n i f o r m shagreen; l a t e r a l b r i s t l e s on segments I I t o V I I u s u a l l y 2-2-2-3-3-3; t e r g i t e V I I I w i t h 3 p a i r s o f small e r b r i s t l e s ; s t e r n i t e V I I I o f male w i t h a rounded extension  caudal  ( F i g . 7-D) and s t e r n i t e V I I I of female w i t h 2  rounded c a u d a l e x t e n s i o n s ; a n a l l o b e s ( F i g . 7-D) each w i t h 4 o r 5 l a t e r a l b r i s t l e s and 4 l a r g e r a p i c a l Larva:—  bristles.  brownish w h i t e , maximum l e n g t h 13 mm.  Antenna:  55 (Fig.  7-E)  f o u r segmented, l e n g t h 0.12  mm.;  p o r t i o n s 31:8:2:3; s e n s o r i u m on b a s a l 1/4 and  antennal of f i r s t  pro-  segment  l a u t e r b o r n organs l a r g e , l o n g e r than segment 3.  l e n g t h 0.84 d o r s a l and  mm.  Head:  (Babine Lake specimens 0.82-0.93 mm.(3);  l a t e r a l margins covered  with fine hairs;  margin of head d a r k and c o n s p i c u o u s ,  caudal  l a t e r a l l y with a  rounded p o s t e r i o r p r o j e c t i o n ( F i g . 7-F); e y e s p o t s ( F i g . u n i t e d and c i r c u l a r ; l a b i a l p l a t e ( F i g . 7-G) w i t h a v e r y broad median t o o t h and l a t e r a l s ; mandible ( F i g . 7-H) and  two p a i r s of  mm.,  pointed  w i t h a long dark a p i c a l tooth  times as l o n g as broad w i t h  f i n e a p i c a l b r i s t l e s ; anal g i l l s mm.  Ecology:— metres. ing  w i d t h 0.26  5 dark l a t e r a l s ; premandible w i t h 3 pointed t e e t h .  Abdomen: a n a l p a p i l l a 2.5-3  0.20  7-F)  l o n g and 0.06  mm.  ( F i g . 7-1)  c o n i c a l about  wide a t base.  L a r v a e were c o l l e c t e d a t depths of 1.0 In 1965  5-6  and  4.5  a d u l t s were emerging from B a b i n e Lake d u r -  the week of May  16 t o May  22.  M a t e r i a l examined:-- 1 l a r v . , l . I V . 6 4 ; 1 l a r v . , 24.VI.64, M a r i o n Lake, B.C.  40*0",  exuv., 17.V.65; 1 pup. Babine L a k e ,  17.V.65; 1 pup.,  16.V.65; 2  pup.  exuv., 18.V.65; 3 l a r v . , 16.V.65,  B.C.  T r i b e ORTHOCLADIINI Genus TRISSOCLADIUS K i e f f e r T r i s s o c l a d i u s K i e f f e r , 1908,  Z. w i s s . I n s e c t B i o l .  IV:1-10,  56 33-39, 78-84 T r i s s o c l a d i u s Brundin,  1956,  Drottningholm. One  Rep.  I n s t . Freshwat.  Res.  37:73-76  s p e c i e s i s known to o c c u r i n Marion L a k e .  T r i s s o c l a d i u s sp. A T h i s s p e c i e s was  not r e a r e d but a p u p a l  respira-  t o r y o r g a n found i n s i d e a mature l a r v a appears i d e n t i c a l to t h a t of the pupa.  T h i s a l o n g w i t h the d a t a on the times  of  emergence s t r o n g l y s u g g e s t s t h a t the l a r v a i s c o r r e c t l y associated. conformis  The  a d u l t male i s s i m i l a r to t h a t of  T.  (Holmgren) and keys t o t h i s s p e c i e s i n B r u n d i n  (1956); however, the a n a l p o i n t of the M a r i o n Lake specimens i s b r o a d e r and ular.  The  the i n n e r l o b e of the c o x i t e i s not as  pupa keys to Hydrobaenus t a t r i c u s (Pagast)  Roback (1957).  This i s a species that Brundin  angin  includes i n  the genus T r i s s o c l a d i u s . Male i m a g o : — t h o r a x and abdomen b l a c k , l e g s brownish b l a c k . Antenna: A.R. segments. 8-12  2.16-2.64, mean 2 . 4 0 ( 7 ) , f l a g e l l u m w i t h  Head: p a l p p r o p o r t i o n s 6:10:10:16; c l y p e u s  with  b r i s t l e s ; t e m p o r a l h a i r s i n s i n g l e rows which n e a r l y  meet at the mid  l i n e of head.  Thorax: pronotum w i t h about  5 f i n e b r i s t l e s ; d o r s o - c e n t r a l b r i s t l e s 7-10 row;  13  s u p r a - a l a r b r i s t l e s 3-4;  in a single  s c u t e l l u m w i t h about 7  b r i s t l e s i n a s i n g l e t r a n s v e r s e row.  Wing: l e n g t h  2.15-  57 2.35 mm.;  base o f R w i t h a few s c a t t e r e d m a c r o t r i c h i a , the  o t h e r membrane v e i n s and wing membrane w i t h o u t m a c r o t r i c h i a ; C extends 0.04 mm. beyond j u n c t i o n o f R44.5.  Legs: L.R.  0.68-0.76, mean 0.72(5); f o r e t i b i a l s p u r 0.06 mm.  long,  about 1.3 times as l o n g as w i d t h o f t i b i a a t apex; f o r e tarsus without and 0.017 mm.  a beard; m i d d l e t i b i a l s p u r s about 0.025 l o n g ; h i n d t i b i a w i t h two s p u r s about 0.048  and 0.015 mm. l o n g and a p r e a p i c a l comb o f 9 o r 10 s p i n e s ; p u l v i l l i minute.  Hypopygium: ( F i g . 7-J) ; a n a l p o i n t broad  w i t h m a c r o t r i c h i a almost t o apex; s t y l e s h o r t and broad, apex d i s t i n c t l y r i g h t  angled.  P u p a : — l e n g t h 3.2-4.6 mm.(4), e x u v i a l i g h t brown.  Res-  p i r a t o r y organ ( F i g . 7-K); s p i n o u s , p o i n t e d and 0.34-0.40 mm. l o n g .  Abdomen: t e r g i t e s I I - V I each w i t h a c a u d a l band  of s p i n u l e s ; t e r g i t e s V I I and V I I I not shagreened, each l a t e r a l margin w i t h 4 f i l a m e n t s and an imbedder s p u r a t t h e c a u d o - l a t e r a l angle  ( F i g . 7 - L ) ; a n a l l o b e s rounded, each  w i t h 26-34 l a t e r a l f i l a m e n t s and 3 t e r m i n a l b r i s t l e s . Larva:—  b r o w n i s h , maximum l e n g t h about 11 mm.;  antennal  p r o p o r t i o n s 26:6:3:4:2.5; s e n s o r i u m on b a s a l 1/5 of f i r s t segment and the a n t e n n a l b l a d e extends t o near t i p o f segment 4.  Head: l e n g t h 0.37-0.45 mm.(5); e y e s p o t s ( F i g .  7-N) s e p a r a t e , d o r s a l eyespot rounded and v e n t r a l one c r e s c e n t shaped; labium w i t h a p a i r o f about 7-rayed palmate bristles;  l a b i a l p l a t e ( F i g . 7-0) w i t h two l a r g e , dark and  58 n a r r o w l y s e p a r a t e d median t e e t h and 5 p a i r s of dark t e e t h ; mandible ( F i g . 7-P)  w i t h a l i g h t a p i c a l t o o t h and  d a r k l a t e r a l t e e t h ; p r e m a n d i b l e ( F i g . 7-Q) a d d i t i o n a l small medial tooth.  b i f i d w i t h an  times as l o n g as  w i d t h at base and w i t h about 7 a p i c a l b r i s t l e s ; a n a l  Ecology:—  mm.  3  Abdomen: a n a l p a p i l l a  brown, w i t h o u t b a s a l s p u r s , about 1.3  p o i n t e d , about 0.16  lateral  l o n g and 0.03  mm.  gills  wide at base.  L a r v a thought to be t h i s s p e c i e s were abundant  at depths t o 4.5  metres.  In 1964  i n March, A p r i l and e a r l y May.  and  1965  a d u l t s emerged  T h i s s p e c i e s appears t o  have a one year l i f e c y c l e i n Marion L a k e . M a t e r i a l examined:-- 1*, 8.IV.64; 1*, 21.IV.64; 65; 5 pup.,  l . I V . 6 4 ; 1 pup.,  15.IV.64; 2 pup.,  l a r v . , 12.11.64; 3 l a r v . , 1.IV.64, Marion L a k e ,  10.IV. 13.V.64; 2 B.C.  Genus HETEROTRISSOCLADIUS Sparck H e t e r o t r i s s o c l a d i u s Sparck, 1922, H e t e r o t r i s s o c l a d i u s B r u n d i n , 1956, Drottningholm. One  Ent. Meddr. 14:92-94 Rep.  I n s t . Freshwat.  Res.  37:80  s p e c i e s o c c u r s i n Marion Lake.  H e t e r o t r i s s o c l a d i u s sp. A T h i s s p e c i e s was  reared.  H. s u b p i l o s u s K i e f f e r  has r e c e n t l y been r e p o r t e d to o c c u r on E l l e s m e r e I s l a n d  59 ( O l i v e r , 1963) but I do not b e l i e v e t h a t t h i s genus has been p r e v i o u s l y recorded  from mainland North A m e r i c a .  The s p e c i -  mens from M a r i o n Lake a r e somewhat i n t e r m e d i a t e between H. marcidus (Walker) and H. grimshawi (Edwards).  The wings o f  the a d u l t s a r e c o m p l e t e l y h a i r y as w i t h H. m a r c i d u s , b u t t h e i r l e n g t h i s t h e same as t h a t g i v e n by Edwards (1929) f o r H. g r i m s h a w i .  The hypopygium i s a l s o i n t e r m e d i a t e between  these two s p e c i e s .  ( B r u n d i n , 1947, F i g u r e s 29 and 30)  Male i m a g o : — t h o r a x b l a c k i s h , abdomen d a r k brown. A.R. 1.44(1), f l a g e l l u m w i t h 13 segments.  Antenna:  Head: p a l p  p o r t i o n s 5:19:15:18; c l y p e u s w i t h 17 b r i s t l e s ;  pro-  temporal  h a i r s i n s i n g l e i r r e g u l a r rows which n e a r l y meet a t t h e mid l i n e o f head.  Thorax; pronoturn w i t h about 5 f i n e  bristles;  d o r s o - c e n t r a l b r i s t l e s 28, i n a d o u b l e i r r e g u l a r row; s u p r a a l a r b r i s t l e s 11 i n a s i n g l e row; s c u t e l l u m w i t h about 20 bristles.  Wings: l e n g t h 2.6 mm.;  wing membrane d e n s e l y  h a i r y ; C does not extend p a s t j u n c t i o n o f a f r i n g e of long h a i r s . 0.06 mm.  R^+CJ'I  squama w i t h  Legs: L.R. 0.89; s p u r on f o r e  long; f o r e tarsus without  tibia  a b e a r d ; s p u r s on m i d d l e  t i b i a 0.042 and 0.032 mm. l o n g ; h i n d t i b i a w i t h two s p u r s 0.08 and 0.032 mm. l o n g and a p r e a p i c a l comb o f 13 s p i n e s ; p u l v i l l i absent.  Hypopygium: ( F i g . 8-A); a n a l p o i n t w i t h  m a c r o t r i c h i a almost t o apex; s t y l e rounded w i t h a p r e a p i c a l lobe which b e a r s a s i n g l e s p i n e . P u p a : — l e n g t h 3.7-4.6 mm.(6), e x u v i a l i g h t brown.  Respir-  a t o r y o r g a n ( F i g . 8-B); s p i n o u s , p o i n t e d and 0.30-0.36 mm.  60 (3) l o n g .  Abdomen: t e r g i t e I not shagreened; t e r g i t e I I  shagreened, the s p i n u l e s l a r g e r near the c a u d a l margin; t e r g i t e s I I I - V I I I u n i f o r m l y shagreened.  F i l a m e n t s on  e r a l margins of segments V I I and V I I I 3-4;  s t e r n i t e V I I I of  male pupa w i t h a c a u d a l band of c o a r s e s p i n e s and of female w i t h two  l o n g imbedded s p i n e s  lat-  (Fig.  8-C)  ( F i g . 8-D);  anal  l o b e s rounded, each w i t h 23-30 m a r g i n a l f i l a m e n t s and 3 d a r k bristles. Larva:—  d a r k green, v e n t r a l p a r t of head b l a c k ; maximum  l e n g t h 7 mm. mm.;  Antenna: ( F i g . 8-E)  0.15  a n t e n n a l p r o p o r t i o n s 30:13:2:7:2.5:2.5; s e n s o r i u m on  b a s a l 1/6  of f i r s t segment and  m i d d l e of segment 4. spots  s i x segmented, l e n g t h  ( F i g . 8-F)  a n t e n n a l b l a d e extends to the  Head: l e n g t h 0.34-0.40 mm.(8); eye-  contiguous,  a n t e r i o r eyespot about 2/3  d i a m e t e r of the p o s t e r i o r one;  l a b i a l p l a t e ( F i g . 8-G)  the with  12 d a r k t e e t h ; the medians the l a r g e s t ; mandible ( F i g .  8-H)  dark w i t h a dark a p i c a l t o o t h and 3 d a r k l a t e r a l t e e t h ; p r e m a n d i b l e ( F i g . 8-1)  s i n g l e but u s u a l l y w i t h a s m a l l  notch  near the t i p . Abdomen: a n a l p a p i l l a as l o n g as broad, w i t h 7 a p i c a l b r i s t l e s and no b a s a l s p u r s ; a n a l g i l l s about 0.14  mm.  ( F i g . 8-J)  l o n g , rounded a p i c a l l y and w i t h a c o n s t r i c t i o n  near c e n t e r . Ecology:— metres. I n 1964  B e n t h i c l a r v a e were abundant at d e p t h s to  Growth was  4.5  u s u a u a l l y r a p i d d u r i n g w i n t e r months.  a d u l t emergence took p l a c e i n A p r i l , May  and  June  61 and a g a i n i n September and October, which s u g g e s t s  that the  s p e c i e s has two g e n e r a t i o n s p e r y e a r . M a t e r i a l e x a m i n e d : — lo", 10.VI.65; 2 pup., 1.IV.64; 1 pup., 15.IV.64; 1 pup. exuv., 27.IV.64; 1 pup. exuv., 6.V.64; 1 pup.  exuv., 8.V.64; 3 l a r v . , 12.11.64; 3 l a r v . , 1.IV.64; 2  l a r v . , 21.VIII.64,  Marion L a k e , B.C.  Genus HETEROTANYTARSUS H e t e r o t a n y t a r s u s Sparck,  Sparck  1922, E n t . Meddr. 14:88-92  H e t e r o t a n y t a r s u s B r u n d i n , 1956, Rep. I n s t . Freshwat. Res. Drottningholm.  37:80-81  One s p e c i e s o c c u r s i n Marion Lake.  Heterotanytarsus sp. A T h i s s p e c i e s was not r e a r e d , but a l l evidence g e s t s t h a t t h e l a r v a has been c o r r e c t l y a s s o c i a t e d .  sug-  This i s  b e l i e v e d t o be t h e f i r s t N o r t h American r e c o r d o f t h e genus and B r u n d i n  (1956) s t a t e s t h a t t h e o n l y known s p e c i e s i n  t h i s genus i s H. a p i c a l i s ( K i e f f e r ) .  The Marion Lake s p e c i -  mens may i n f a c t be t h i s s p e c i e s as t h e a d u l t s agree w e l l w i t h the d e s c r i p t i o n s of Brundin  (1956) and Edwards  (1929).  I n a d d i t i o n , t h e l a r v a keys t o Metriocnemus a p i c a l i s i n Roback (1957) and t o H. a p i c a l i s i n Thienemann, 1944 and the pupa keys t o t h e genus H e t e r o t a n y t a r s u s i n Hennig  (1950).  62  One  d i f f e r e n c e i s t h a t the p u p a l r e s p i r a t o r y organ does not  have a d i v e r t i c u l u m at i t s base as does t h a t of H.  apicalis.  A second d i f f e r e n c e i s t h a t t h i s s p e c i e s has a one  year  l i f e c y c l e whereas H.  a p i c a l i s has two g e n e r a t i o n s per  i n Swedish Lakes ( B r u n d i n ,  1949).  Male i m a g o : — head antenna and l i g h t e r brown.  Antenna: A.R.  e l l u m w i t h 13 segments. c l y p e u s w i t h 7-9  year  t h o r a x dark brown, abdomen 0.52-0.62, mean 0 . 5 7 ( 6 ) , f l a g -  Head: p a l p p r o p o r t i o n s 3.5:8:9:11;  b r i s t l e s ; t e m p o r a l h a i r s i n s i n g l e rows  which extend m e d i a l l y about as f a r as v e r t e x a n g l e s of eyes. Thorax: pronotum w i t h about 8 f i n e b r i s t l e s ; d o r s o - c e n t r a l b r i s t l e s 8-10; bristles.  s u p r a - a l a r b r i s t l e s 4-5;  Wing: l e n g t h 1.35-1.60 mm.;  row of m a c r o t r i c h i a , r e m a i n i n g  scutellum with 4 R, R^ and R 4 5 w i t h a +  membrane v e i n s and wing mem-  brane bare except f o r s c a t t e r e d m a c r o t r i c h i a at wing apex; C e x t e n d s 0.03  mm.  beyond j u n c t i o n of R4+5J squama w i t h a  f r i n g e of about 6 l o n g h a i r s ; a n a l l o b e reduced. 0.53-0.57, f o r e t i b i a w i t h a s p u r about 0.04  mm.  Legs:  L.R.  long; f o r e  t a r s u s w i t h a b e a r d , l o n g e r h a i r s 4 times as l o n g as diame t e r of t a r s u s ; m i d d l e t i b i a w i t h two s p u r s about 0.02 0.015  mm.  l o n g ; h i n d t i b i a l s p u r s about 0.04  and 0.01  and mm.  l o n g , o c c a s i o n a l l y the s m a l l e r s p i n e i s absent;, p r e a p i c a l comb of h i n d t i b i a w i t h about 8 s p i n e s ; p u l v i l l i s m a l l but d i s t i n c t at a m a g n i f i c a t i o n of 400.  Hypopygium: ( F i g . 8-K);  a n a l p o i n t v e r y s h o r t ; apex of s t y l e r i g h t  angled.  63 Pupa:-- l e n g t h 3.0-3.3 mm.(4), e x u v i a u n i f o r m l y d a r k brown. R e s p i r a t o r y organ: ( F i g . 8 - L ) ; s p i n u o u s , and 0.26-0.27 mm.  long.  pointed  apically  Abdomen: t e r g i t e I not shagreened;  t e r g i t e I I w i t h a band o f c o a r s e s p i n u l e s a l o n g t h e c a u d a l margin and f i n e s p i n u l e s on t h e r e s t o f t h e c a u d a l h a l f o f the t e r g i t e ; t e r g i t e s I I I t o VI w i t h shagreen on most o f t h e d i s c , t h e .coarsest s p i n u l e s b e i n g near t h e c a u d a l margin; t e r g i t e s V I I and V I I I w i t h a c a u d a l row o f s p i n u l e s and a few s m a l l e r s c a t t e r e d s p i n u l e s j u s t a n t e r i o r t o t h i s row; l a t e r a l f i l a m e n t s on segments V I I and V I I I 4-4; a n a l  lobes  each w i t h 16-20 m a r g i n a l f i l a m e n t s and 3 t e r m i n a l b r i s t l e s . Larva:—  dark green, v e n t r a l p a r t o f head b l a c k ; maximum  l e n g t h 4.5 mm.  Antenna: ( F i g . 8-M); f o u r segmented; l e n g t h  0.31 mm. and a n t e n n a l p r o p o r t i o n s 48:59:8:3; s e n s o r i u m on b a s a l 1/6 o f f i r s t segment and a n t e n n a l b l a d e extends t o near t i p o f segment 3. (Fig.  8-N) c o n t i g u o u s ,  Head: l e n g t h 0.27-0.34(6); e y e s p o t s a n t e r i o r eyespot about 2/3 the diam-  e t e r o f t h e p o s t e r i o r one; l a b i a l p l a t e ( F i g . 8-0) w i t h 14 t e e t h , t h e medians and f i r s t  l a t e r a l s reduced i n s i z e ; man-  d i b l e w i t h a d a r k a p i c a l t o o t h and 3 d a r k l a t e r a l t e e t h ; p r e m a n d i b l e ( F i g . 8-P) w i t h f o u r t e e t h .  Abdomen: a n a l  p a p i l l a about 2.5 times as l o n g as b r o a d , w i t h 8 a p i c a l b r i s t l e s and w i t h o u t b a s a l s p u r s ; a n a l g i l l s about 0.12 mm.  ( F i g . 8-Q)  l o n g , rounded a p i c a l l y and w i t h a marked  c o n s t r i c t i o n near c e n t e r .  64 Ecology:—  L a r v a of t h i s s p e c i e s are common at a l l depths i n  M a r i o n Lake.  I n 1964  the a d u l t s emerged i n May  and e a r l y  June. M a t e r i a l e x a m i n e d : — lo", 6.V.64; 5o"o", ?.V.64; 4 pup.  exuv.,  18.V.64; 1 l a r v . , 1.IV.64; 3 l a r v . , 15.IV.64; 1 l a r v . , 29.IV. 64; 2 l a r v . , 13.V.64, Marion Lake,  B.C.  Genus CRICOTOPUS van d e r Wulp C r i c o t o p u s van d e r Wulp, 1874,  T i j d s c h r . E n t . 17:132  C r i c o t o p u s B r u n d i n , 1956,  I n s t . Freshwat. Res. D r o t t n i n g -  Rep.  holm. 37:109-114 One  s p e c i e s o c c u r s i n M a r i o n Lake.  Cricotopus t r i c i n c t u s Chironomus t r i c i n c t u s Meigen, 1818, der bekannten e u r o p a j s c h e n  (Meigen) Systematische  beschreibung  z w e i f l u g e l i g e n Insekten.  1:41 C r i c o t o p u s t r i c i n c t u s Edwards, 1929,  T r a n s , e n t . Soc. Lond.  77:319 T h i s s p e c i e s was almost c e r t a i n l y  not r e a r e d , but the l a r v a i s  correctly associated.  The  a d u l t male keys  to C. t r i c i n c t u s ( M e i g e n ) , i n Johannsen and Townes (1952) and the pupa and  l a r v a both key t o a c o u p l e t c o n t a i n i n g C.  t r i c i n c t u s * C. t r i f a s c i a t u s (Panzer)  and C.  sylvestris  65 ( F a b r i c i u s ) i n Roback (1957).  The Marion Lake specimens a r e  l a r g e r than t h e o t h e r d e s c r i b e d specimens o f t h i s s p e c i e s , but t h e s i m i l a r i t y o f o t h e r c h a r a c t e r s s t r o n g l y s u g g e s t s t h a t they a r e o n l y a l a r g e r form o f C. t r i c i n c t u s . Male imago:-— antenna and p a l p s dark brown; t h o r a x mixed w i t h y e l l o w ; femora brown, becoming b l a c k  black,  apically;  t i b i a y e l l o w w i t h a b l a c k band a t e i t h e r end; f o r e t a r s u s b l a c k ; m i d d l e and h i n d t a r s i b l a c k a t t i p s , but b a s a l  seg-  ments y e l l o w i s h ; abdominal t e r g i t e s I I , I I I , V, V I I I and I X b l a c k ; t h e a n t e r i o r 2/3 o f t e r g i t e V I , and t h e median 1/6 of t e r g i t e IV brownish b l a c k ; t h e r e m a i n i n g gites yellow.  abdominal t e r -  Antenna: A.R. 1.87-2.13, mean 2 . 0 ( 3 ) ,  e l l u m w i t h 13 segments.  flag-  Head: p a l p p r o p o r t i o n s 7:13:16:21;  c l y p e u s w i t h 10-11 b r i s t l e s ; t e m p o r a l h a i r s i n s i n g l e rows which extend m e d i a l l y as f a r o r s l i g h t l y f a r t h e r than v e r t e x a n g l e s o f eyes; eyes covered  with microtrichia.  Thorax:  pronotum w i t h about 8 f i n e b r i s t l e s ; d o r s o - c e n t r a l b r i s t l e s v e r y s m a l l , about 26 i n an i r r e g u l a r band; s u p r a - a l a r b r i s t l e s 4 o r 5; s c u t e l l u m w i t h about 11 c o a r s e b r i s t l e s i n a t r a n s v e r s e row.  Wing: l e n g t h 2.25-2.35 mm.;  of R w i t h about 11 m a c r o t r i c h i a , r e m a i n i n g  basal half  membrane v e i n s  and wing membrane w i t h o u t m a c r o t r i c h i a ; C extends s l i g h t l y (0.02 mm.)  beyond j u n c t i o n o f R4.+.5; squama f r i n g e d and w i t h  a d a r k spot near j u n c t i o n w i t h a l u l a .  Legs: L.R. 0.50-0.52;  f o r e t i b i a l s p u r about 0.07 mm. l o n g ; f o r e t a r s u s w i t h o u t a beard; m i d d l e t i b i a w i t h two s p u r s about 0.04 and 0.03 mm.  66 l o n g ; h i n d t i b i a w i t h two s p u r s about 0.07 and 0.035 mm. l o n g ; p r e a p i c a l comb o f h i n d t i b i a w i t h about 17 s p i n e s i n a s i n g l e row; p u l v i l l i p r e s e n t  and c o n s p i c u o u s .  Abdomen:  t e r g i t e s I I - I V each w i t h a median row o f 4-6 c o a r s e  black  spines.  Hypopygium: ( F i g . 8-R); s t y l e broad and about  0.13 mm.  l o n g , i n n e r lobe o f c o x i t e narrow and e l o n g a t e .  P u p a : — l e n g t h 5.0-5.5 mm.(5); e x u v i a u n i f o r m l y l i g h t brown. R e s p i r a t o r y organ: ( F i g . 8-S); t u b u l a r , w i t h o u t and 0.27-0.30 mm.  long.  spinules  Abdomen: t e r g i t e s I , V I I and V I I I  not shagreened; t e r g i t e s I I t o VI w i t h u n i f o r m  coarse  shagreen; l a t e r a l margins o f segments IV t o V I I I  without  f i l a m e n t s but w i t h 2 o r 3 p a i r s o f f i n e h a i r s each; a n a l l o b e s ( F i g . 8-T) rounded, w i t h o u t m a r g i n a l f i l a m e n t s and w i t h 3 o r r a r e l y 4 short coarse Larva:—  bristles.  brown, maximum l e n g t h 9 mm.  Antenna: ( F i g . 8-U);  a n t e n n a l p r o p o r t i o n s 26:6:4:2:2; a n t e n n a l b l a d e extends t o m i d d l e o f segment 3; l a u t e r b o r n organs l a r g e , a t l e a s t as l o n g as segment 3.  Head: l e n g t h 0.58-0.70(2); e y e s p o t s  (Fig.  and o b l i q u e ; l a b i a l p l a t e ( F i g . 8-W)  8-V) s e p a r a t e  d a r k w i t h 11 t e e t h , t h e median and f i r s t  l a t e r a l s are  l a r g e r t h a n o t h e r l a t e r a l s and o f t e n a r e weakly notched; mandible ( F i g . 8-X) w i t h a s h o r t dark a p i c a l t o o t h and 4 dark l a t e r a l s ; p r e m a n d i b l e ( F i g . 8-Y) b i f i d , w i t h rounded teeth.  Abdomen: segments IV t o I X each w i t h a t u f t o f  about 14 h a i r s near each c a u d o - l a t e r a l margin; a n a l p a p i l l a  67 about 1.5 times as l o n g as b r o a d , each w i t h about 7  apical  b r i s t l e s and w i t h o u t b a s a l s p u r s ; a n a l g i l l s t a p e r e d , about 0.19  mm.  l o n g and 0.06  mm.  wide at base.  E c o l o g y : — T h i s i s a r a r e s p e c i e s i n M a r i o n Lake.  Larvae  were t a k e n o n l y i n emergence t r a p s , which s u g g e s t s t h a t t h e y are a s s o c i a t e d w i t h a q u a t i c , p l a n t s r a t h e r than w i t h the bottom.  W i r t h (1957) r e p o r t s t h a t t h i s i s the case w i t h two  r e l a t e d s p e c i e s , C. t r i f a s c i a t u s and C. s y l v e s t r i s .  In 1963  and 1964 a d u l t s of the M a r i o n Lake s p e c i e s emerged d u r i n g September and O c t o b e r . M a t e r i a l examined:—  20*0", 18.IX.63; lo", 7.X.63; 4 pup.  exuv.,  18.IX.63; 1 pup. exuv., 29.IX.63; 1 l a r v . , 2.VII.63; 1 l a r v . , 9.VII.63, M a r i o n Lake,  B.C.  Genus PSECTROCLADIUS K i e f f e r Psectrocladius Kieffer,  1906, Me'm.  Soc. S c i . Brux. 30:356  P s e c t r o c l a d i u s B r u n d i n , 1956, Rep. I n s t . Freshwat. Res. D r o t t n i n g h o l m . 37:116-118 At l e a s t seven s p e c i e s a r e known t o o c c u r i n M a r i o n Lake.  They a l l d i f f e r from any of the d e s c r i p t i o n s  encountered and most o r a l l of them a r e p r o b a b l y new,  how-  e v e r , the l i t e r a t u r e on t h i s v e r y l a r g e genus i s w i d e l y s c a t t e r e d and many s p e c i f i c d e s c r i p t i o n s have undoubtedly been o v e r l o o k e d .  68 P s e c t r o c l a d i u s sp. A T h i s s p e c i e s was  reared.  The  l a r v a and pupa w i l l  not key out s a t i s f a c t o r i l y i n Roback, 1957. median t e e t h of the l a r v a l l a b i a l p l a t e and  The  joined  the p o i n t e d  a n a l l o b e s of the pupa are u n u s u a l f o r the genus. Male i m a g o : — t h o r a x , eyes and a n t e n n a l p e d i c l e s dark brown; a n t e n n a l f l a g e l l u m and  l e g s u n i f o r m l y brown; abdomen g r e e n -  i s h brown, t e r g i t e s browner than s t e r n i t e s . 1.94-2.15(2); f l a g e l l u m w i t h 13 segments. t i o n s 4:9:8:14; c l y p e u s b r o a d , w i t h 7-9  Antenna: Head: p a l p  bristles;  A.R. propor-  temporal  h a i r s i n s i n g l e rows which extend m e d i a l l y t o p o i n t s about h a l f way  between the v e r t e x a n g l e s of eyes and  of head.  the mid  Thorax: pronotum w i t h about 5 f i n e h a i r s ;  central bristles  mm.(3); p r o x i m a l 1/4  Wing: l e n g t h 2.15-2.40  of R w i t h s c a t t e r e d m a c r o t r i c h i a the  remaining  membrane v e i n s and wing membrane w i t h o u t  trichia.  Legs: L.R.  0.06  mm.  mm.  0.79-0.85; f o r e t i b i a l s p u r 0.06  mm.  a b e a r d ; middle t i b i a w i t h a s i n g l e s p u r  l o n g ; h i n d t i b i a w i t h a s i n g l e s p u r about  l o n g ; p r e a p i c a l comb of h i n d t i b i a w i t h at l e a s t  clumped s p i n e s ; p u l v i l l i rounded and c o n s p i c u o u s . ( F i g . 9-A); angled;  macro-  times as l o n g as w i d t h of t i b i a at apex;  fore tarsus without about 0.05  dorso-  10; s u p r a - a l a r b r i s t l e s 4 and s c u t e l l u m w i t h  a t r a n s v e r s e row of 3 o r 4 b r i s t l e s .  l o n g , about 1.5  line  a n a l p o i n t l o n g and b a r e ; apex of s t y l e  20  Hypopygium: right  i n n e r lobe of c o x i t e rounded and m e d i a l s t r u t at base  69 of c o x i t e n e a r l y p a r a l l e l w i t h the l o n g a x i s of  coxite.  P u p a : — l e n g t h 0.48-0.53 mm.(8), e x u v i a brown.  Respiratory  organ: ( F i g . 9-B);  t u b u l a r , 0.19-0.25 mm.  few s p i n u l e s near apex.  l o n g and w i t h a  Abdomen: t e r g i t e I not  shagreened;  t e r g i t e I I w i t h an e l e v a t e d c a u d a l band o f curved  spines;  t e r g i t e I I I l i g h t l y shagreened and w i t h a p o s t e r i o r band of s p i n u l e s ; t e r g i t e s IV t o V I I I shagreened and w i t h a c i r c u l a r p a t c h of c o a r s e s p i n e s near c e n t e r of d i s c . a n d a c a u d a l band of s p i n e s which are c o a r s e on t e r g i t e s IV and V ( F i g .  9-C)  and much s m a l l e r on t e r g i t e s VI and V I I ; t e r g i t e V I I I  sha-  greened but w i t h o u t  c o a r s e s p i n e s ; l a t e r a l h a i r s and  fila-  ments on segments V t o V I I I 4-4-4-5, the p r o j e c t i o n s on segments V and VI are h a i r l i k e and f i l a m e n t o u s ; a n a l l o b e s ( F i g . 9-D)  those on V I I and V I I I p o i n t e d , each w i t h 40-52  m a r g i n a l f i l a m e n t s and 3 o r 4 dark b r i s t l e s . Larva:— 9-E);  p a l e green, maximum l e n g t h 8 mm.  l e n g t h about 0.16  s e n s o r i u m on b a s a l 2/5  mm.,  a n t e n n a l p r o p o r t i o n s 36:10:7:5:2;\  of f i r s t segment and  extends to the m i d d l e o f segment 4. ( 5 ) ; e y e s p o t s ( F i g . 9-F)  Antenna: ( F i g .  separate;  w i t h a v e r y broad median t o o t h and  antennal  blade  Head: l e n g t h 0.41-0.52 labial plate (Fig.  9-G)  5 dark l a t e r a l t e e t h ;  p a r a l a b i a l p l a t e s l a r g e and p o i n t e d l a t e r a l l y ; mandible ( F i g . 9-H)  w i t h a l o n g p o i n t e d a p i c a l t o o t h and 3  darker  l a t e r a l s ; p r e m a n d i b l e s i n g l e , broad and s i c k l e shaped; labrum w i t h a p a i r of 4 o r 5 rayed palmate b r i s t l e s .  Abdomen:  70 a n a l p a p i l l a b r o w n i s h , about 3 times as l o n g as b r o a d , w i t h 5 a p i c a l b r i s t l e s and 2 s m a l l b a s a l s p u r s ; a n a l r o d - l i k e , about 0.20 Ecology:— I n 1964  mm.  l o n g and 0.015  mm.  wide.  L a r v a e were abundant a t depths of 0-4  a d u l t emergence l a s t e d from May  metres.  11 u n t i l June 8.  M a t e r i a l e x a m i n e d : — lo", 13.V.64; Id", 20.V.64; 4 pup. 18.V.64; 1 pup.  exuv., 19.V.64; 3 pup.  gills  exuv.,  exuv., 20.V.64; 1  l a r v . , l . I V . 6 4 ; 2 l a r v . , 15.IV.64; 2 l a r v . , 13.V.64, M a r i o n Lake,  B.C.  P s e c t r o c l a d i u s sp. B T h i s s p e c i e s was  not r e a r e d , but the l a r v a i s  almost c e r t a i n l y c o r r e c t l y a s s o c i a t e d .  The  w i l l not key out s a t i s f a c t o r i l y i n Roback  l a r v a and pupa (1957).  Male i m a g o : — t h o r a x b r o w n i s h orange; abdominal t e r g i t e s , l e g s and  a n t e n n a l f l a g e l l u m l i g h t brown; v e n t r a l p a r t of  abdomen green; e y e s , a n t e n n a l p e d i c l e s and postnotum d a r k brown.  Antenna: A.R.  w i t h 13 segments. b r o a d , w i t h 4-6  1.75-2.03, mean 1.86(3), f l a g e l l u m  Head: p a l p p r o p o r t i o n s 5:8:8:12; c l y p e u s  b r i s t l e s ; t e m p o r a l h a i r s i n s i n g l e rows  which extend m e d i a l l y t o p o i n t s about 2/3 v e r t e x a n g l e s of eyes to the mid d o r s o - c e n t r a l b r i s t l e s 9-12 b r i s t l e s 3-5;  the d i s t a n c e from  l i n e of head.  i n a s i n g l e row;  Thorax:  supra-alar  s c u t e l l u m w i t h about 4 b r i s t l e s .  Wing:  71 l e n g t h 2.05-2.25 mm., t r i c h i a , remaining macrotrichia. mm.  base of R w i t h a few s c a t t e r e d macro-  membrane v e i n s and wing membrane w i t h o u t  Legs: L.R.  l o n g , about 1.5  0.78-0.85; f o r e t i b i a l s p u r  0.07  times as l o n g as w i d t h of t i b i a at  apex; f o r e t a r s u s w i t h o u t  a beard; middle t i b i a w i t h  two  s p u r s about 0.05  and 0.02  mm.  long; hind t i b i a with  s p u r s about 0.06  and 0.02  mm.  l o n g ; p r e a p i c a l comb of h i n d  two  t i b i a w i t h a t l e a s t 20 clumped s p i n e s ; p u l v i l l i rounded conspicuous.  Hypopygium: ( F i g . 9-1);  anal point long  and  and  t a p e r i n g ; apex of s t y l e r i g h t a n g l e d ; m e d i a l s t r u t at base of c o x i t e almost at r i g h t a n g l e s t o the l o n g a x i s of P u p a : — l e n g t h 4.4-5.0 mm.(6), e x u v i a l i g h t brown. t o r y organ: ( F i g . 9 - J ) ; t u b u l a r 0.22-0.27 mm. a few s c a t t e r e d s p i n u l e s near apex.  coxite. Respira-  l o n g and  with  Abdomen: t e r g i t e I  w i t h o u t shagreen; t e r g i t e I I w i t h an e l e v a t e d c a u d a l band of curved  s p i n e s ; t e r g i t e I I I w i t h a c a u d a l band of s h o r t  s p i n e s ; t e r g i t e s I V - V I I f a i n t l y shagreened and w i t h a  cir-  c u l a r p a t c h of c o a r s e s p i n e s near the c e n t e r of each d i s c (Fig.  9-K);  c a u d a l s p i n e band i s s t r o n g on t e r g i t e s IV  and  V^ reduced on t e r g i t e VI and absent on t e r g i t e V I I ; t e r g i t e V I I I f a i n t l y shagreened and w i t h o u t  coarse s p i n e s ; anal  l o b e s p o i n t e d , each w i t h 23-29 l a t e r a l f i l a m e n t s and dark  3-5  bristles.  Larva:—green, l e n g t h 0.15  mm.;  maximum l e n g t h 8 mm.  Antenna: ( F i g . 9-L);  a n t e n n a l p r o p o r t i o n s 31:10:7:4:2;  72 s e n s o r i u m on b a s a l 1/3 o f f i r s t segment and a n t e n n a l b l a d e extends t o near t i p of' segment 4.  Head: l e n g t h 0.44-0.53  mm.(5) e y e s p o t s s e p a r a t e , the d o r s a l one rounded and the v e n t r a l one c r e s c e n t shaped; labrum w i t h a p a i r of 4 o r 5 rayed palmate b r i s t l e s ; l a b i a l p l a t e ( F i g . 9-M) median t o o t h which may  w i t h a broad  be weakly notched and 5 p a i r s of d a r k  l a t e r a l s ; p a r a l a b i a l s l a r g e and p o i n t e d l a t e r a l l y ; w i t h a l o n g brownish a p i c a l t o o t h and 3 dark premandible ( F i g . 9-N)  mandible  laterals;  s i n g l e , broad and h e a v i l y pigmented.  Abdomen: a n a l p a p i l l a ( F i g . 9-0)  b r o w n i s h , about 3 times as  l o n g as b r o a d , w i t h 5 a p i c a l b r i s t l e s and 1 o r 2 s m a l l b a s a l s p u r s ; a n a l g i l l s r o d - l i k e , about 0.17  mm.  l o n g and 0.02  mm.  wide. E c o l o g y : — L a r v a e of t h i s s p e c i e s were abundant at depths of 3.5-5  metres and almost absent at o t h e r d e p t h s .  In  1964  emergence l a s t e d from J u l y 5 u n t i l September 19. M a t e r i a l examined:—  3dd,  1 9 . V I I I . 6 4 ; 1 pup., 22.VII.64; 6  pup. exuv., 1 9 . V I I I . 6 4 ; 5 l a r v . , 22.VII.64, M a r i o n Lake,  B.C.  P s e c t r o c l a d i u s sp. C T h i s s p e c i e s was r e a r e d .  The l a r v a w i l l not key  out i n Roback (1957) and the pupa keys t o P.  stratiotis  ( K i e f f e r ) , but i s not t h i s s p e c i e s . Male i m a g o : — t h o r a x dark brown, l e g s and antenna brown,  73 abdomen g r e e n i s h brown.  Antenna: A.R.  ( 5 ) , f l a g e l l u m w i t h 13 segments.  1.73-3.23, mean  Head: p a l p  7:12:13:16; c l y p e u s b r o a d , w i t h 7-13  1.93  proportions  b r i s t l e s ; temporal h a i r s  i n s i n g l e s h o r t rows which extend m e d i a l l y about as f a r as v e r t e x a n g l e s of eyes. i n a s i n g l e row;  Thorax: d o r s o - c e n t r a l b r i s t l e s  s u p r a - a l a r b r i s t l e s 2-4;  b r i s t l e s i n a t r a n s v e r s e row.  7-11  scutellum with  7-9  Wing: l e n g t h 2.2-2.3 mm.;  base  of R w i t h a few s c a t t e r e d m a c r o t r i c h i a , o t h e r membrane v e i n s and wing membrane w i t h o u t m a c r o t r i c h i a ; C extends about mm.  beyond j u n c t i o n of R4+5.  t i b i a w i t h a s p u r about 0.06  Legs: L.R. mm.  0.74-0.77; f o r e  long; f o r e tarsus without  b e a r d ; m i d d l e t i b i a w i t h a s i n g l e s p u r about 0.04 h i n d t i b i a w i t h a s i n g l e s p u r about 0.06  mm.  mm.  Hypopygium: ( F i g . 9-P);  mm.  long.  rounded  inner  angled.  P u p a : — l e n g t h 4.5-4.8 mm.(5), e x u v i a brown. organ: ( F i g . 9-Q);  long;  apex of a n a l p o i n t  b a r e ; s t y l e 0.11-0.12 mm.long and rounded a p i c a l l y ; l o b e of c o x i t e r i g h t  a  l o n g and a p r e -  a p i c a l comb of at l e a s t 25 clumped s p i n e s ; p u l v i l l i and c o n s p i c u o u s .  0.03  Respiratory  s p i n o u s , rounded a p i c a l l y and 0.27-0.36  Abdomen: t e r g i t e I not shagreened; t e r g i t e I I  w i t h an e l e v a t e d c a u d a l band of s p i n e s ; t e r g i t e s I I I to VI l i g h t l y shagreened and w i t h p a i r e d p a t c h e s of c o a r s e on c e n t e r of d i s c ( F i g . 9-R)  and  spines  a c a u d a l band of s p i n e s ;  t e r g i t e s V I I and V I I I f a i n t l y shagreened, w i t h 4 and  5 pairs  of l a t e r a l f i l a m e n t s r e s p e c t i v e l y ; a n a l l o b e s rounded,each w i t h 32-37 m a r g i n a l f i l a m e n t s and 3 t e r m i n a l b r i s t l e s .  74 L a r v a : — green, maximum l e n g t h 7 mm.  Antenna:  ( F i g . 9-S);  a n t e n n a l p r o p o r t i o n s 28:6:3:2:1.5; s e n s o r i u m on b a s a l 1/7 of segment 1 and a n t e n n a l b l a d e extends t o near t i p of segment 4.  Head: l e n g t h 0.40-0.45 mm.(6); e y e s p o t s s e p a r a t e , d o r s a l  eyespot around and v e n t r a l one c r e s c e n t shaped; l a b i u m w i t h a p a i r of 7 r a y e d palmate b r i s t l e s ; l a b i a l p l a t e ( F i g s . 9-U)  9-T,  w i t h a broad o f t e n t r u n c a t e d median t o o t h and 5 p a i r s  of d a r k l a t e r a l t e e t h ; mandible w i t h a d a r k a p i c a l t o o t h which i s s h o r t e r t h a n the combined w i d t h of the 3 d a r k e r a l t e e t h ; permandible ( F i g . 9-V)  narrow and s i c k l e  lat-  shaped.  Abdomen: a n a l p a p i l l a about t w i c e as l o n g as b r o a d , w i t h 5 a p i c a l b r i s t l e s and no b a s a l s p u r s ; a n a l g i l l s c u r v e d , rounded a p i c a l l y and about 0.12 mm.  mm.  ( F i g . 9-W)  l o n g and  0.04  wide.  E c o l o g y : — L a r v a e of t h i s s p e c i e s are common at a l l depths i n Marion Lake.  There appears t o be two g e n e r a t i o n s p e r  y e a r and i n 1964 the f i r s t p e r i o d of emergence was A p r i l and i n May and the second was  i n late  i n September and  early  October. M a t e r i a l examined:—  lo", 2.V.64; 1°\ 6.V.64; 1°*, 8.V.65;  lrf, 7.IV.64; Id", 7.V.64; 4 pup. exuv. ,. 18.V.64; 1 pup. 25.IV.64;  2 l a r v . , 15.IV.64;  2.IX.64, M a r i o n Lake,  B.C.  exuv.,  2 l a r v . , 21.VIII.63; 2 l a r v . ,  75 P s e c t r o c l a d i u s sp. D T h i s s p e c i e s was r e a r e d .  The l a r v a keys t o P.  e l a t u s Roback i n Roback (1957); however, t h e l a b i a l p l a t e o f the l a r v a i s v e r y d i f f e r e n t from t h a t o f P. e l a t u s . pupa keys t o P. s t r a t i o t i s t a i n l y not t h i s  The  ( K i e f f e r ) but t h e l a r v a i s c e r -  species.  Male i m a g o : — t h o r a x brown, abdomen g r e e n i s h brown. Antenna: A.R. 1.53-1.75, mean 1.64(4), f l a g e l l u m w i t h 13 segments. Head: p a l p p r o p o r t i o n s 4:9:10:14; c l y p e u s b r o a d , w i t h 8-13 bristles;  temporal h a i r s i n s i n g l e rowswhich extend m e d i a l l y  as f a r as o r s l i g h t l y p a s t t h e v e r t e x a n g l e s o f eyes. Thorax: pronotum w i t h about 5 f i n e b r i s t l e s ; bristles  dorso-central  7-9 i n a s i n g l e row; s u p r a - a l a r b r i s t l e s 3-4;  s c u t e l l u m w i t h about 6 b r i s t l e s .  Wing: l e n g t h 1.70-2.05  mm.;  base o f R w i t h about 3 m a c r o t r i c h i a , t h e o t h e r membrane v e i n s and wing membrane w i t h o u t m a c r o t r i c h i a ; C extends about 0.02 mm. beyond j u n c t i o n o f R4+5.  Legs: L.R. 0.75-0.81; f o r e  t i b i a w i t h a s p u r about 0.05 mm. l o n g ; f o r e t a r s u s w i t h o u t a b e a r d ; m i d d l e t i b i a w i t h 2 s p u r s about 0.04 and 0.01 mm. long ( o c c a s i o n a l l y the s h o r t e r spur i s absent); hind t i b i a w i t h a s p u r about 0.06 mm. l o n g and u s u a l l y a second s p u r t h a t may be as l o n g as 0.02 mm.; p r e a p i c a l comb o f h i n d t i b i a N  w i t h a t l e a s t 20 clumped s p i n e s ; p u l v i l l i rounded and conspicuous.  Hypopygium: ( F i g . 10-A); a n a l p o i n t l o n g and  bare; s t y l e 0.095-0.11 mm.  long.  76 \ \ P u p a : — l e n g t h 3.8-4.5 mm.(12), e x u v i a l i g h t brown.  Res-  p i r a t o r y organ: ( F i g . 10-B); s p i n o u s , rounded a p i c a l l y and 0.27-0.35 mm.  long.  Abdomen: t e r g i t e I bare; t e r g i t e s I I  and I I I f a i n t l y shagreened and w i t h a c a u d a l band o f s p i n e s and s p i n u l e s ; t e r g i t e s IV t o VI f a i n t l y shagreened and w i t h a c a u d a l row o f s p i n e s and p a i r e d p a t c h e s o f c o a r s e s p i n e s near t h e c e n t r a l p a r t o f d i s c ( F i g . 10-C); t e r g i t e s V I I and V I I I l i g h t l y shagreened and u s u a l l y w i t h 4 and 5 p a i r s of l a t e r a l f i l a m e n t s r e s p e c t i v e l y ; a n a l l o b e s ;  rounded,  each w i t h 21-28 m a r g i n a l f i l a m e n t s and 3 t e r m i n a l b r i s t l e s . L a r v a : - - l i g h t green, maximum l e n g t h 7 mm. 10-D); l e n g t h about 0.11 mm.;  Antenna ( F i g .  a n t e n n a l p r o p o r t i o n s 30:5:3:  2:1.5; s e n s o r i u m on b a s a l 1/6 o f f i r s t segment and a n t e n n a l blade extends t o end o f segment 4.  Head: l e n g t h 0.39-0.47  mm.(6); e y e s p o t s ( F i g . 10-E) s e p a r a t e ; 6-8 rayed palmate b r i s t l e s ; broad n a r r o w l y s e p a r a t e d  labrum w i t h a p a i r o f  l a b i a l p l a t e ( F i g . 10-F) w i t h  median t e e t h and 5 p a i r s o f dark  l a t e r a l t e e t h ; mandible ( F i g . 10-G) w i t h a long, l i g h t a p i c a l t o o t h and 3 dark l a t e r a l t e e t h ; p r e m a n d i b l e ( F i g . 10H) broad and s i n g l e .  Abdomen: a n a l p a p i l l a  as l o n g as b r o a d , w i t h 5 a p i c a l b r i s t l e s basal spurs; anal g i l l s  about 2.5 times  and 1 o r 2 s m a l l  ( F i g . 10-1) t a p e r i n g , p o i n t e d  a p i c a l l y , about 0.23 mm. l o n g and 0.025 mm. wide a t base. Ecology:—  L a r v a e o f t h i s s p e c i e s were common a t depths  from 0.5 t o 4.0 metres.  There a p p a r e n t l y a r e two g e n e r a t i o n s  77 p e r y e a r and i n 1964 the f i r s t p e r i o d of emergence was i n May and June and t h e second was d u r i n g August and  September.  M a t e r i a l examined:—  rf  1°", 2.V.64; 1<*, 6 . V I I I . 6 3 ; 2°' , 8 . V I I I .  63; 2 pup. exuv., 18.IX.63; 3 pup. exuv., 22.IX.63; 1 pup. exuv., 29.IX.63; 1 pup. exuv., 6.V.64; 4 pup. exuv., 18.V.64; 1 pup. exuv., 1.VI.64; 2 l a r v . , 12.11.64;  1 larv.,  1.IV.64;  1 l a r v . , 15.IV.64; 3 l a r v . , 29.IV.64; 1 l a r v . , 2.IX. 64, M a r i o n Lake,  B.C.  P s e c t r o c l a d i u s sp. E T h i s s p e c i e s was not r e a r e d and the l a r v a i s unknown.  The pupa keys t o P. s t r a t i o t i s ( K i e f f e r ) i n Roback  ( 1 9 5 7 ) , b u t the a d u l t male i s d i f f e r e n t from t h a t d e s c r i b e d r  by Edwards (1929). Male i m a g o : —  brownish.  lum w i t h 13 segments.  Antenna: A.R.  1.0-1.13(2), f l a g e l -  Head: p a l p p r o p o r t i o n s 3:8:7:12.5;  c l y p e u s b r o a d , w i t h about 14 b r i s t l e s ; t e m p o r a l h a i r s i n s i n g l e s h o r t rows which extend m e d i a l l y about as f a r as v e r t e x a n g l e s of eye.  Thorax: d o r s o - c e n t r a l b r i s t l e s about  8; s u p r a - a l a r b r i s t l e s 2-3; s c u t e l l u m w i t h 4-5 Wing: l e n g t h 1.4 mm.; Legs: L.R.  bristles.  wing membrane w i t h o u t m a c r o t r i c h i a .  0.72(1); f o r e t i b i a w i t h a s p u r 0.045 mm.  long,  about 1.4 t i m e s as l o n g as w i d t h of t i b i a a t apex; f o r e tarsus without a beard; middle t i b i a with a s i n g l e spur about 0.035 mm.  l o n g ; h i n d t i b i a w i t h a s i n g l e s p u r about  78 0.05 mm.  l o n g and a p r e a p i c a l comb w i t h a t l e a s t 20 clumped  s p i n e s ; p u l v i l l i rounded and c o n s p i c u o u s .  Hypopygium: ( F i g .  1 0 - J ) ; a n a l p o i n t bare and t a p e r i n g ; s t y l e narrow a p i c a l l y and about 0.075 mm.  long.  P u p a : — l e n g t h 3.0-3.4 mm.(4), e x u v i a almost but t i n g e d w i t h brown.  transparent  R e s p i r a t o r y organ: ( F i g . 10-K);  s p i n o u s , rounded a p i c a l l y and 0.21-0.23 mm. l o n g . t e r g i t e I not shagreened; t e r g i t e I I and I I I f i n e l y  Abdomen: sha-  greened and w i t h a c a u d a l band o f s p i n e s ; t e r g i t e s IV t o VI f i n e l y shagreened and each w i t h a c a u d a l row o f c o a r s e s p i n e s and a s i n g l e o v a l p a t c h o f c o a r s e s p i n e s near t h e c e n t e r o f t h e d i s c ; t e r g i t e s V I I and V I I I w i t h u n i f o r m  fine  shagreen, no c o a r s e s p i n e s , and w i t h 4 and 5 p a i r s o f l a t e r a l f i l a m e n t s r e s p e c t i v e l y ; a n a l l o b e s rounded each w i t h 13-16  m a r g i n a l f i l a m e n t s and 3 t e r m i n a l b r i s t l e s .  Ecology:—  T h i s i s a r a r e s p e c i e s i n M a r i o n Lake.  I n 1964  a d u l t s were c o l l e c t e d from l a t e August u n t i l mid October i n emergence t r a p s s e t o v e r depths o f 0.5-3.0 metres. M a t e r i a l examined:-- Id", 18.IX.63; lcf.pup., 13.IX.64; l d pup.,  18.IX.63; 1 pup. exuv., 18.IX.63; 1 pup. exuv., 26.  V I I I . 6 4 , M a r i o n Lake, B.C.  P s e c t r o c l a d i u s sp. F T h i s s p e c i e s was n o t r e a r e d and no l a r v a has been  79 a s s o c i a t e d w i t h the pupa and a d u l t .  I t i s possible that  the  l a r v a t e n t a t i v e l y a s s o c i a t e d w i t h P s e c t r o c l a d i u s sp. G i s i n f a c t the l a r v a of P. sp. F.  The male imago of t h i s  i s d e s c r i b e d from a male pupa t h a t was The  species  s t a r t i n g to emerge.  a d u l t keys to P s e c t r o c l a d i u s i n B r u n d i n  (1956) and  the  pupa and a d u l t both resemble P. s o r d i d e l l u s ( Z e t t . ) , however, the a d u l t male does have a s m a l l e r a n a l p o i n t and has a more a n g u l a r  inner lobe.  The  the c o x i t e  abdominal t e r g i t e s of  the pupa a l s o l a c k s p i n e p a t c h e s on the c e n t r a l p a r t of  the  disc. Male i m a g o : — b l a c k i s h . 13 segments.  Antenna: A.R.  2.21,  flagellum with  Head: c l y p e u s w i t h 12 b r i s t l e s .  Thorax:  pronotum w i t h 11 f i n e b r i s t l e s near the v e n t r a l margin 5 b r i s t l e s on e i t h e r s i d e of the mid  l i n e of  and  thorax;  a c r o s t i c h i a l b r i s t l e s f i n e , about 5 i n number; d o r s o - c e n t r a l b r i s t l e s about 14; s u p r a - a l a r b r i s t l e s 6, s c u t e l l u m w i t h about 8 b r i s t l e s . l o n g , about 1.7  L e g s : f o r e t i b i a w i t h a s p u r 0.08  times as l o n g as w i d t h of t i b i a at apex;  m i d d l e t i b i a w i t h s p u r s about 0.04 t i b i a w i t h one without  mm.  s p u r about 0.065 mm.  and 0.015 l o n g and  mm.  long; hind  apparently  a second s p u r ; p r e a p i c a l comb of h i n d t i b i a  with  about 13 s p i n e s i n a s i n g l e row;. p u l v i l l i rounded and spicuous.  con-  Hypopygium: ( F i g . 10-L); a n a l l o b e v e r y s h o r t  i n n e r lobe of c o x i t e a n g u l a r . P u p a : — l e n g t h 4.4  mm.,  e x u v i a u n i f o r m l y l i g h t brown.  and  80 R e s p i r a t o r y organ: ( F i g . 10-M); t u b u l a r , p o i n t e d  apically  and w i t h s c a t t e r e d rounded s c a l e s on t h e m i d d l e p o r t i o n . Abdomen: t e r g i t e I not shagreened; t e r g i t e I I w i t h an e l e v a t e d c a u d a l band o f s p i n e s ; t e r g i t e s I I I t o V I I I w i t h a c a u d a l row o f s p i n e s and w i t h f i n e shagreen on t h e c a u d a l 1/3 o f each t e r g i t e ; c a u d a l s p i n e s on t e r g i t e s V I - V I I I ( F i g , 10-N) much l a r g e r than those on a n t e r i o r t e r g i t e s ;  tergites  V I I and V I I I w i t h 4 and 5 p a i r s o f l a t e r a l f i l a m e n t s r e s p e c t i v e l y ; a n a l l o b e s rounded, each w i t h about 42 m a r g i n a l f i l a m e n t s and 3 t e r m i n a l b r i s t l e s . Ecology:—  T h i s s p e c i e s i s r a r e i n M a r i o n Lake and t h e o n l y  specimens c o l l e c t e d were t a k e n i n June and J u l y o v e r depths of 0.5-3.0 metres. M a t e r i a l e x a m i n e d : — 1°" pup., 17.VI1.64, M a r i o n L a k e , B.C.  P s e c t r o c l a d i u s sp. G T h i s s p e c i e s was not r e a r e d and t h e l a r v a i s o n l y tentatively associated.  The M a r i o n Lake s p e c i e s resembles  the European s p e c i e s P. conjungens (Brundin)  but t h e male  imago i s s m a l l e r and t h e a n a l p o i n t o f t h e hypopygium i s broader.  The w h o r l o f l o n g s c a l e s on t h e h i n d t i b i a l  spur  of t h e a d u l t resembles t h a t o f a d u l t s o f t h e genus Chaetoc l a d i u s but t h e s t r u c t u r e o f t h e p u l v i l l i p l a c e s t h i s i n t h e genus P s e c t r o c l a d i u s .  species  The pupa resembles those o f  P. p i l o s u s Roback and P. f l a v u s (Johannsen) but d i f f e r s from  81 pupa of P. p i l o s u s by the absence of a median s p i n e  patch  on t e r g i t e s I I I t o IV and from t h a t of P. f l a v u s by i t s s h o r t e r r e s p i r a t o r y organ and by h a v i n g o n l y about h a l f  as  many f i l a m e n t s on the a n a l l o b e . Male i m a g o : — antenna and brownish black. 13 segments. w i t h 31-32  l e g s brown, t h o r a x and abdomen  Antenna: A.R.  2.23-2.64(2); f l a g e l l u m w i t h  Head: p a l p p r o p o r t i o n s 8:12.5:11.5:16; c l y p e u s  b r i s t l e s ; t e m p o r a l h a i r s i n s i n g l e l o n g rows which  n e a r l y meet at the mid  l i n e of head.  Thorax: pronotum w i t h  about 15 b r i s t l e s ; a c r o s t i c h i a l b r i s t l e s , s m a l l curved wards; d o r s o - c e n t r a l b r i s t l e s about 27 i n an  back-  irregular  d o u b l e row;  s u p r a - a l a r b r i s t l e s i n a t r a n s v e r s e row.  Wing:  l e n g t h 2.35  mm.(l); R and R^ w i t h a row of m a c r o t r i c h i a , the  o t h e r membrane v e i n s w i t h o u t m a c r o t r i c h i a ; wing membrane w i t h a few m a c r o t r i c h i a at wing apex. f o r e t i b i a w i t h a s p u r about 0.07 without 0.02 mm.  mm.  mm.  Legs: L.R.  0.72-0.78;  long; fore tarsus  a b e a r d ; m i d d l e t i b i a w i t h two s p u r s about 0.06 l o n g ; h i n d t i b i a w i t h two s p u r s about 0.07  and  and 0.02  l o n g , the l o n g e r one w i t h a c o n s p i c u o u s w h o r l of p o i n t e d  s c a l e s ; p r e a p i c a l comb of h i n d t i b i a w i t h 14 s p i n e s ; rounded and c o n s p i c u o u s .  Hypopygium: ( F i g . 10-0)  pulvilli  anal point  v e r y broad and bare near apex; i n n e r lobe of c o x i t e rounded. P u p a : — l e n g t h 5.1  mm.(l), e x u v i a l i g h t brown.  organ: ( F i g . 10-P); 0.25  mm.  o v e r l a p p i n g rounded s c a l e s .  l o n g , a p i c a l 4/5  Respiratory  covered  with  Abdomen: t e r g i t e I not shagreened;  82 t e r g i t e I I f i n e l y shagreened and w i t h an e l e v a t e d band of curved  s p i n e s a l o n g c a u d a l margin; t e r g i t e s I I I to V I I I  f a i n t l y shagreened and w i t h c a u d a l bands o r rows of s p i n e s , the c a u d a l s p i n e s on t e r g i t e s V I I and V I I I l o n g e r occasionally b i f i d 1-4  and  ( F i g . 10-Q); t e r g i t e s IV to VI each have  l o n g e r s p i n e s on the c e n t r a l p a r t of d i s c ; f i l a m e n t s on  l a t e r a l margins of segments IV t o V I I I 4-4-4-4-5; a n a l  gills  rounded^ each w i t h about 65 m a r g i n a l f i l a m e n t s and 2 o r 3 small hair l i k e Larva:—  bristles.  g r e e n , maximum l e n g t h 7 mm.  l e n g t h 0.21  mm.,  a n t e n n a l p r o p o r t i o n s 56:10:5:4:2.5; sen-  s o r i u m on b a s a l 1/10 to end of setment 3. spots ous;  ( F i g . 10-S)  of segment 1 and a n t e n n a l b l a d e Head:  extends  l e n g t h 0.48-0.53 mm.(5); eye-  h o r i z o n t a l , c i r c u l a r and n e a r l y c o n t i g u -  labrum w i t h a p a i r of 6-9  l a b i a l p l a t e ( F i g . 10-T) medians and  Antenna: ( F i g . 10-R);  rayed palmate b r i s t l e s ;  w i t h broad n a r r o w l y  separated  5 p a i r s of d a r k l a t e r a l s ; mandible ( F i g .  10-U)  w i t h a l o n g l i g h t a p i c a l t o o t h and 3 dark l a t e r a l t e e t h ; p r e m a n d i b l e ( F i g . 10-V) short medial  tooth.  w i t h a l o n g a p i c a l t o o t h and  Abdomen: a n a l p a p i l l a ( F i g . 10-W)  a about  1.7  times as l o n g as g r e a t e s t w i d t h , w i t h 5 a p i c a l b r i s t l e s  and  two  mm.  l o n g and 0.3  l a r g e b a s a l s p u r s ; a n a l g i l l s r o d - l i k e , about  Ecology:—  mm.  0.13  wide.  T h i s i s a r a r e s p e c i e s i n M a r i o n Lake.  In  1964  a d u l t s were c o l l e c t e d d u r i n g October i n emergence t r a p s s e t  83 o v e r depths of l e s s than 1.0  metres.  M a t e r i a l e x a m i n e d : — lo", 22.X.64; lo", 29.X.64; 1 pup.  exuv.,  29.X.64; 1 l a r v . , 29.IV.64; 1 l a r v . , 27.V.64; 2 l a r v . , VI.64, Marion L a k e ,  10.  B.C.  T r i b e METRIOCNEMINI Genus PARAKIEFFERIELLA T h i e n . Parakiefferiella  Thienemann, 1936,  S t e t t i n , e n t . Z t g . 97:43  P a r a k i e f f e r i e l l a B r u n d i n , 1956, Rep.  Inst.  Freshwat.  Res.  D r o t t n i n g h o l m . 37:148-151 Two  s p e c i e s are known to o c c u r i n Marion Lake,  Parakiefferiella Spaniotoma ( E u k i e f f e r i e l l a )  coronata  B.C.  (Edwards)  c o r o n a t a Edwards, 1929,  Trans.  e n t . Soc. Lond. 77:354 Parakiefferiella  c o r o n a t a B r u n d i n , 1956, Rep.  Inst.  Freshwat.  Res. D r o t t n i n g h o l m . 37:152-153 T h i s s p e c i e s was tentatively  associated.  not r e a r e d and the l a r v a  The Marion Lake a d u l t s and pupa are  s l i g h t l y s m a l l e r than t h e d e s c r i b e d specimens of P. but key t o t h i s s p e c i e s i n B r u n d i n (1956). emergence i s v e r y s i m i l a r  i s only  coronata,  The p e r i o d of  t o t h a t f o r P. c o r o n a t a i n Swedish  h i g h l a n d l a k e s and except f o r the s m a l l d i f f e r e n c e i n s i z e  84 (wing  l e n g t h 0.85-0.95 mm.  compared to 1.2  mm.  P. c o r o n a t a ) they are m o r p h o l o g i c a l l y v e r y Male i m a g o : — head and t e r g i t e s I I I and  o r more f o r  similar.  t h o r a x b r o w n i s h b l a c k ; abdominal  IV grey, t e r g i t e s V and  V I I I brownish b l a c k ,  remainder of abdomen l i g h t e r i n c o l o r ; femora brown, t i b i a and  tarsi whitish.  Antenna: A.R.  f l a g e l l u m w i t h 13 segments. c l y p e u s w i t h 5-8  0.37-0.64,. mean 0.45(4),  Head: p a l p p r o p o r t i o n s 2:3:5:9;  b r i s t l e s ; t e m p o r a l h a i r s i n s i n g l e rows  which extend m e d i a l l y about as f a r as v e r t e x a n g l e s of eyes. Thorax: d o r s o - c e n t r a l b r i s t l e s 4-6; and s c u t e l l u m w i t h 2 b r i s t l e s .  one  supra-alar  bristle  Wing: l e n g t h 0.85-0.95;  wing membrane and membrane v e i n s w i t h o u t m a c r o t r i c h i a ; a n a l l o b e s reduced and squama w i t h o u t L.R.  a f r i n g e of h a i r s .  0.425-0.465; f o r e t i b i a l s p u r and  t a r s a l beard b o t h  a b s e n t ; m i d d l e t i b i a w i t h a s i n g l e s p u r about 0.01 h i n d t i b i a w i t h a s i n g l e s p u r about 0.02  Legs:  mm.  mm.  long;  l o n g and  p r e a p i c a l comb of about 13 s p i n e s i n a s i n g l e row.  a  Hypo-  pygium: ( F i g . l l - A ) ; i ; a n a l p o i n t a b s e n t ; l o b e of c o x i t e p o i n t e d and  angular.  P u p a : — l e n g t h 1,6-1.9 mm.(7); abdominal t e r g i t e s I-V e x u v i a b r o w n i s h b l a c k , the remainder of e x u v i a R e s p i r a t o r y o r g a n : ( F i g . 11-B); o v a l , about 0.06 and w i t h a few s p i n u l e s near base.  of  transparent. mm.  long  Abdomen: t e r g i t e I w i t h  a c a u d a l band of s p i n u l e s ; t e r g i t e s I I - V I each w i t h a  caudal  and  without  a c e n t r a l band of s p i n u l e s ; t e r g i t e s V I I and V I I I  85 s p i n u l e s ; t e r g i t e V I I w i t h 4 p a i r s of l a t e r a l h a i r s and t e r g i t e V I I I w i t h 4 p a i r s of l a t e r a l f i l a m e n t s ; a n a l ( F i g . 11-C) Larva:—  lobes  p o i n t e d each w i t h 3 b r i s t l e s and no f i l a m e n t s .  g r e e n i s h w h i t e , l e n g t h 2.5  4 segmented and 0.05  mm.  s e n s o r i u m on b a s a l 1/4  mm.  Antenna: ( F i g . 11-D);  l o n g ; a n t e n n a l p r o p o r t i o n s 11:4:2.5:1;  of segment 1 and a n t e n n a l blade  extends  t o t i p of segment 3; l a u t e r b o r n organs l a r g e , more than h a l f as l o n g as segment 3.  Head: l e n g t h 0.25  mm.;  e y e s p o t s con-  t i g u o u s i n a h o r i z o n t a l p l a n e and the a n t e r i o r eyespot i s about 2/3  the d i a m e t e r of the p o s t e r i o r one;  ( F i g . 11-E)  w i t h a broad p a l e c e n t r a l p l a t e which has  minute median t e e t h , l a t e r a l t e e t h a b s e n t . 11-F)  labial plate  Mandible ( F i g .  p a l e w i t h a v e r y l o n g narrow a p i c a l t o o t h and 4 minute  laterals.  Abdomen: a n a l p a p i l l a s l i g h t l y t a p e r e d ,  l o n g as w i d t h at base and w i t h a t l e a s t 5 a p i c a l a n a l g i l l s t a p e r i n g and p o i n t e d a p i c a l l y , 0.19 0.06  two  mm.  about as  bristles;  mm.  long  and  wide at base.  Ecology:—  T h i s was  a common s p e c i e s at depths of 0.5-3.0  metres and absent f r o m the deeper a r e a s .  I n 1964  a d u l t s of  t h i s s p e c i e s emerged from mid August u n t i l , m i d September. M a t e r i a l examined:-- lo", 1 7 . V I I I . 6 4 ;  lo", 19.VIII.64; 20*0",  2.IX.64; 1 pup.,  26.VIII.64;  2.IX.64; 1 pup. Lake,  B.C.  19.VIII.64;  3 pup.,  exuv., 2 3 . V I I I . 6 4 ;  2  pup.,  1 l a r v . , 12.VI.64, M a r i o n  86 Parakiefferiella nigra P a r a k i e f f e r i e l l a n i g r a Brundin, Res. D r o t t n i n g h o l m .  Brundin  1949, Rep. I n s t . Freshwat.  30:827-828  T h i s s p e c i e s was r e a r e d , but t h e l a r v a l e x u v i a was l o s t so t h e a s s o c i a t i o n o f t h e l a r v a i s not c e r t a i n .  The  l a r v a c o u l d not be keyed o u t i n Hennig (1950) but i t i s close to that of P a r a k i e f f e r i e l l a .  The pupa keys t o  P a r a k i e f f e r i e l l a i n Hennig's key and t h e pupa and a d u l t male b o t h key t o P. n i g r a i n B r u n d i n  (1956).  The a d u l t male  d i f f e r s from B r u n d i n ' s specimens i n some r e s p e c t s . i s higher  The A.R.  (1.15-1.24 compared t o about 0.9) and t h e wing  l e n g t h i s l e s s (1.60-1.65 mm. compared t o 1.7-2.5 mm.). Male i m a g o : — t h o r a x and most o f abdomen b l a c k ; abdominal t e r g i t e s V I I and V I I I grey.  Antenna: A.R. 1.15-1.24(2),  f l a g e l l u m w i t h 13 segments.  Head: p a l p p r o p o r t i o n s 4:7:7:11;  c l y p e u s w i t h 5-7 b r i s t l e s ; t e m p o r a l h a i r s i n s i n g l e rows which extend m e d i a l l y t o p o i n t s about 1/3 t h e d i s t a n c e from the v e r t e x a n g l e s o f eyes t o t h e mid l i n e o f head.  Thorax:  pronotum w i t h o u t b r i s t l e s ; d o r s o - c e n t r a l b r i s t l e s 6-7; s u p r a - a l a r b r i s t l e s 3 and s c u t e l l u m w i t h about 4 b r i s t l e s . Wing: l e n g t h 1.60-1.65; wing membrane and membrane v e i n s without m a c r o t r i c h i a ; anal lobe moderately w e l l developed; C extends about 0.07 beyond j u n c t i o n o f R4+5»  Legs: L.R.  0.50-0.56; f o r e t i b i a w i t h a s p u r about as l o n g as w i d t h of t i b i a a t apex; m i d d l e t i b i a w i t h s p u r s about 0.02 and  87 0.015 mm.  l o n g ; h i n d t i b i a w i t h a s i n g l e s p u r 0.03 mm.  long  and a p r e a p i c a l comb o f 12-14 s p i n e s i n a s i n g l e row; p u l v i l l i present  but v e r y minute.  a n a l p o i n t a b s e n t ; s t y l e curved enlarged;  Hypopygium: ( F i g . 11-G); and the a p i c a l t h i r d  i n n e r lobe o f c o x i t e e l o n g a t e ,  t r i c h i a but w i t h o u t  slightly  apex w i t h macro-  microtrichia.  P u p a : — l e n g t h 2.8-3.1 mm.(8), abdominal t e r g i t e s I I t o V o f e x u v i a d a r k brown; t e r g i t e s I and VI l i g h t brown, remainder of e x u v i a t r a n s p a r e n t .  R e s p i r a t o r y organ: ( F i g . 11-H); o v a l  0.05-0.07 mm. l o n g and w i t h o u t  spinules.  Abdomen: t e r g i t e  I not shagreened; t e r g i t e s I I t o VI w i t h a t r a n s v e r s e  caudal  band o f s p i n u l e s and a t r i a n g u l a r p a t c h o f s p i n u l e s on t h e c e n t r a l p a r t o f d i s c , t h i s p a t c h much reduced on t e r g i t e V I ; t e r g i t e s V I I and V I I I not shagreened, each w i t h 4 p a i r s of l a t e r a l h a i r s ; a n a l l o b e s ( F i g . 11-1) each w i t h 3 b r i s t l e s and no f i l a m e n t s o r h a i r s . Larva:—  g r e y i s h green, maximum l e n g t h 4.0 mm.  ( F i g . 1 1 - J ) ; f o u r segmented and about 0.05 mm.  Antenna: long;  anten-  n a l p r o p o r t i o n s 10:7:1:0.7; s e n s o r i u m on b a s a l 1/4 o f f i r s t segment and a n t e n n a l b l a d e extends t o t i p o f segment 4. Head: l e n g t h 0.17-0.23(3); e y e s p o t s ( F i g . 11-K) and  contiguous  i n a h o r i z o n t a l p l a n e ; l a b i a l p l a t e ( F i g . 11-L) w i t h a  v e r y l a r g e t r a n s p a r e n t median t o o t h and 6 p a i r s o f l a t e r a l t e e t h , t h e s i x t h l a t e r a l s a r e more s h a r p l y p o i n t e d neighbors;  mandible ( F i g . 11-M) w i t h a l o n g l i g h t  than apical  88 t o o t h and 3 d a r k l a t e r a l t e e t h , t h e f i r s t  l a t e r a l i s some-  what t r u n c a t e d and t h e o t h e r two a r e p o i n t e d ; p r e m a n d i b l e ( F i g . 11-N) b i f i d and l i g h t i n c o l o r .  Abdomen: a n a l  p a p i l l a about as l o n g as b r o a d , w i t h a t l e a s t 4 a p i c a l b r i s t l e s ; a n a l g i l l s tapered and p o i n t e d a p i c a l l y ,  about 0.04  mm. l o n g and 0.01 mm. wide a t base. E c o l o g y : — L a r v a e , o f t h i s s p e c i e s were common a t d e p t h s o f more than one metre and i n 1964 a d u l t emergence o c c u r r e d d u r i n g A p r i l and May. M a t e r i a l examined:—  lo", 6.V.64; lo", 8.V.65; 1 pup.  exuv.,  2.V.64; 2 pup. exuv., 6 . V I I I . 6 4 ; 5 pup. exuv., 8 . V I I I . 6 4 ; 3 l a r v . , 15.IV.64, M a r i o n Lake, B.C.  Genus CORYNONEURA W i n n e r t z Corynoneura W i n n e r t z , 1846, S t e t t i n . E n t . Z t g . 7:12 Corynoneura B r u n d i n , 1956, Rep. I n s t .  Freshwat. Res.  D r o t t n i n g h o l m . 37:172 One s p e c i e s o c c u r s i n M a r i o n Lake.  Corynoneura sp. A T h i s s p e c i e s was n o t r e a r e d and t h e l a r v a and pupa a r e o n l y t e n t a t i v e l y  associated.  The t i p o f antenna o f  the one male specimen a v a i l a b l e was l o s t so a s p e c i f i c  89 d e t e r m i n a t i o n was i m p o s s i b l e .  The l a r v a keys t o C. t a r i s  Roback i n Roback (1957) and t h e pupa keys t o c o u p l e t 2 where t h e low number of f i l a m e n t s on the a n a l l o b e s s u g g e s t s t h a t i t i s more c l o s e l y r e l a t i o n t o C. t a r i s than t o C. c e l e r i p e s Winnertz.  The M a r i o n Lake specimens a r e however,  much l a r g e r than C. t a r i s and a r e p r o b a b l y Male i m a g o : — brownish b l a c k .  Head: p a l p p r o p o r t i o n s 2:3:  3.5:7; c l y p e u s w i t h about 9 b r i s t l e s ( l ) . without  b r i s t l e s ; dorso-central b r i s t l e s  bristles mm.;  a new s p e c i e s .  1-2; s c u t e l l u m w i t h 2 b r i s t l e s .  Thorax: pronotum 5; s u p r a - a l a r Wing: l e n g t h 1.02  wing membrane and membrane v e i n s w i t h o u t m a c r o t r i c h i a ;  C f u s e d w i t h R, l e n g t h from l e v e l o f a r c u l u s o n l y 3/10 o f the wing l e n g t h ; a n a l l o b e l a c k i n g and squama w i t h o u t a f r i n g e of h a i r s . 0.025 mm.  Legs: L.R. 0.57; f o r e t i b i a w i t h a s p u r  l o n g , about 1.3 times as l o n g as w i d t h o f t i b i a a t  apex; f o r e t a r s u s w i t h o u t  a b e a r d ; middle t i b i a w i t h a s i n g l e  s p u r about 0.02 mm. l o n g ; h i n d t i b i a apex e n l a r g e d ,  about  1.6 times as wide as remainder o f t i b i a ; h i n d t i b i a w i t h 2 s p u r s , one s t r a i g h t and 0.04 mm.  l o n g and the o t h e r  curved  and 0.015 mm. l o n g ; p r e a p i c a l comb o f h i n d t i b i a w i t h about 18 s p i n e s i n a s i n g l e row. curved  Hypopygium: ( F i g . 11-0); s t y l e  and narrow a p i c a l l y ; c o x i t e w i t h a c o n s p i c u o u s i n n e r  lobe. P u p a : — l e n g t h 1.6 mm.(l); e x u v i a l i g h t brown. organ: a p p a r e n t l y absent.  Abdomen: t e r g i t e s  Respiratory  without  90 d i s t i n c t i v e shagreen; t e r g i t e s V I - V I I I each w i t h 4 p a i r s of l a t e r a l f i l a m e n t s ; anal lobes  ( F i g . 11-P)  18 m a r g i n a l f i l a m e n t s and w i t h o u t Larva:—  terminal b r i s t l e s .  p a l e green, maximum l e n g t h 2.5  mm.  11-Q); f o u r segmented; l e n g t h about 0.44 1.6  rounded, each w i t h  Antenna: ( F i g .  mm.,  approximately  times as l o n g as head; a n t e n n a l p r o p o r t i o n s 83:41:43:2;  a n t e n n a l blade about 2/5  as l o n g as segment 2.  0.25-0.30 mm.(2); e y e s p o t s ( F i g . 11-R)  Head:  contiguous  length  and  in a  h o r i z o n t a l plane; epipharyngeal  comb w i t h 14 s h o r t even  t e e t h ; l a b i a l p l a t e ( F i g . 11-S)  w i t h 13 t e e t h , the median  t o o t h v e r y minute; mandible ( F i g . 11-T) t o o t h and 4 dark l a t e r a l s , the f i r s t a p i c a l and second l a t e r a l .  with a short  l a t e r a l l o n g e r than  Abdomen: a n a l p a p i l l a , about as  l o n g as w i d e , w i t h 4 a p i c a l b r i s t l e s ; a n a l g i l l s t a p e r i n g , about 0.50  mm.  apical  l o n g and 0.08  mm.  slightly  wide a t base;  p o s t e r i o r p r o l e g s w i t h a c o n s p i c u o u s b a s a l s p u r ( F i g . 11-U). Ecology:—  The  o n l y l a r v a e c o l l e c t e d were taken i n emergence  t r a p s d u r i n g J u l y , August and September. nearing pupation  Most of them were  and t h i s a l o n g w i t h the f a c t t h a t the  few  pupa and a d u l t s c o l l e c t e d were taken i n emergence t r a p s d u r i n g August, September and O c t o b e r i n d i c a t e s t h a t t h i s s p e c i e s emerges i n l a t e summer and  autumn.  M a t e r i a l e x a m i n e d : — lo", 18.IX.63; 1 pup., 15.VII.63; 1 l a r v . , 2 6 . V I I I . 6 4 ,  ?.VIII.64;  Marion Lake,  B.C.  1 larv.,  91  S u b f a m i l y CHIRONOMINAE Adults of t h i s subfamily follows.  The c r o s s - v e i n m-cu  can be c h a r a c t e r i z e d as  i s always a b s e n t , the s t y l e s  of t h e hypopygium l a c k t e r m i n a l s p i n e s and are d i r e c t e d rigidly  backwards.  The l e g r a t i o i s almost always g r e a t e r  than 1.0 and the f o r e t i b i a has an a p i c a l s c a l e t h a t may o r may not t e r m i n a t e  i n a spur.  The m i d d l e and h i n d  tibia  each have a p a i r o f a p i c a l combs which may be u n i t e d .  The  pupa have c l o s e d r e s p i r a t o r y organs which may be branched, the caudo l a t e r a l margin of abdominal segment V I I I u s u a l l y bears a comb o r s p u r and the a n a l l o b e s a r e always f r i n g e d with filaments.  The l a r v a a r e g e n e r a l l y r e d and have non  r e t r a c t i l e antennae.  The e y e s p o t s a r e u s u a l l y s e p a r a t e and  s t r i a t e d p a r a l a b i a l p l a t e s are p r e s e n t . At l e a s t 22 s p e c i e s t h a t b e l o n g t o t h i s o c c u r i n M a r i o n Lake.  subfamily  The emergence p e r i o d s o f most o f  them a r e of r a t h e r s h o r t d u r a t i o n and the l a r v a e  generally  have a v e r y r e s t r i c t e d d i s t r i b u t i o n w i t h i n the l a k e .  T r i b e CHIRONOMINI Genus CRYPTOCHIRONOMUS K i e f f e r Cryptochironomus K i e f f e r , 1918, E n t . M i t t . _ 7 : 3 8 Cryptochironomus Townes, 1945, Am. M i d i . Nat. 34;96-97 Two s p e c i e s a r e known t o o c c u r i n M a r i o n Lake.  92 Cryptochironomus s p . A T h i s s p e c i e s was not r e a r e d but t h e l a r v a i s almost c e r t a i n l y c o r r e c t l y a s s o c i a t e d .  The a d u l t male shows  some s i m i l a r i t i e s t o t h a t o f C. f u l v u s (Johannsen) but f r o n t a l t u b e r c l e s are present  and c o n s p i c u o u s .  I n a d d i t i o n the  c e p h a l i c t u b e r c l e s o f t h e pupa a r e s i m p l e not b i f i d as Sublette  (1964a) i n d i c a t e s i s the case w i t h t h e pupa o f C.  fulvus. Male i m a g o : — t h o r a x b l a c k i s h ; l e g s , antenna and abdomen b l a c k i s h brown. ments.  Antenna: A.R. 3.93, f l a g e l l u m w i t h 11 seg-  Head: p a l p p r o p o r t i o n s  11:28:17:25; c l y p e u s w i t h 33  b r i s t l e s ; f r o n t a l t u b e r c l e s s a c l i k e , l e n g t h about 2.5 t i m e s g r e a t e s t w i d t h ; t e m p o r a l h a i r s i n bands o f 2 o r more rows which extend m e d i a l l y t o p o i n t s about 1/3 the d i s t a n c e from the v e r t e x a n g l e s o f eyes t o t h e mid l i n e o f head.  Thorax:  pronotum p r o j e c t s t o o r s l i g h t l y beyond mesoscutum; d o r s o c e n t r a l b r i s t l e s i n a d o u b l e i r r e g u l a r row; s u p r a - a l a r b r i s t l e s 9, i n a s i n g l e row; s c u t e l l u m w i t h a t r a n s v e r s e band o f b r i s t l e s , m e d i a l l y t h e b r i s t l e s a r e i n 3 o r 4 i r r e g u l a r rows and l a t e r a l l y they a r e i n a s i n g l e row. l e n g t h 4.3 mm. R,  R\  and o u t e r 1/3 o f R4+5 w i t h a row o f  m a c r o t r i c h i a ; wing membrane w i t h o u t R  2+3  w  i  d  e  ly  below r-m.  separated  Wing:  m a c r o t r i c h i a ; R-^ and  a t t i p ; c u b i t a l f o r k almost d i r e c t l y  Legs: L.R. 1.36; apex o f f o r e t i b i a w i t h a  t r i a n g u l a r s p u r l e s s s c a l e ; f o r e t a r s a l beard s p a r s e ;  middle.  93  t i b i a with separate  combs, each w i t h a s h o r t t e r m i n a l  h i n d t i b i a l combs s i m i l a r to t h o s e on m i d d l e t i b i a .  spine5 Hypo-  pygium: ( F i g . 13-A); w i t h a l o n g , narrow a n a l p o i n t ; s u p e r i o r appendage l o b e shaped, covered w i t h m i c r o t r i c h i a and  about t w i c e as l o n g as broad; i n f e r i o r appendage s m a l l  about as l o n g as s u p e r i o r appendage; s t y l e s l i g h t l y P u p a : — l e n g t h 11.2-12.5 mm.(2). 13-B); l o n g c o n i c a l and bristle. I and  curved.  Cephalic tubercle: ( F i g .  u s u a l l y with a short p r e a p i c a l  R e s p i r a t o r y organ: f i l a m e n t o u s .  Abdomen: t e r g i t e s  I I honey combed and w i t h a p o s t e r i o r band of  s p i n u l e s ; t e r g i t e s I I I t o V ( F i g . 13-C)  coarse  honey combed  and  w i t h a s i n g l e c a u d a l row of s h o r t s p i n e s ; t e r g i t e VI honey combed a n t e r i o r l y g r a d i n g i n t o f i n e shagreen, p o s t e r i o r p a r t of t e r g i t e bare except f o r a row of coarse  spines  along  margin; t e r g i t e V I I bare except f o r a c a u d a l band of  coarse  s p i n e s ; t e r g i t e V I I I w i t h f i n e shagreen near c a u d o - l a t e r a l margin and w i t h o u t  a comb o r s p u r ;  l a t e r a l f i l a m e n t s on  segments V to V I I I 4-4-4-5; segment IX w i t h a two  pronged  t e r m i n a l p r o j e c t i o n ( F i g . 13-D); a n a l f i n s each w i t h 120+  lateral filaments.  Larva:—  red,, maximum l e n g t h 13 mm.  Antenna: ( F i g . 13-E);  a n t e n n a l p r o p o r t i o n s 33:15:13:1.5:2; s e n s o r i u m on 1/3  105-  of f i r s t segment and  end of segment 2. 13-F)  antennal blade  attached  distal near o u t e r  Head: l e n g t h 0.50-0.60(4); e y e s p o t s ( F i g .  s e p a r a t e , d o r s a l eyespot a n t e r i o r of v e n t r a l one;  94 l a b i a l p l a t e ( F i g . 13-G) w i t h a l i g h t rounded t o o t h l e s s median a r e a and 5 p a i r s o f l a t e r a l t e e t h , w i d t h o f c l e a r a r e a 4.1-5.6 times i n t o w i d t h o f l a b i a l p l a t e ; mandible ( F i g . 13-H) w i t h a v e r y l o n g c l u b shaped a c c e s s o r y  tooth;  p r e m a n d i b l e ( F i g . 13-1) w i t h 5 l o n g narrow t e e t h .  Abdomen:  a n a l p a p i l l a about as l o n g as b r o a d , w i t h 8 t e r m i n a l b r i s t l e s ; anal g i l l s  ( F i g . 13-J) s h o r t , p o i n t e d , about 3 times as l o n g  as b r o a d . Ecology:—  T h i s i s a r a r e s p e c i e s i n M a r i o n Lake.  Larvae  were taken a t depths from 0.5-4.5 metres and i n 1964 the a d u l t s emerged d u r i n g June. M a t e r i a l examined:-— lo", 17.VI.64; 1 pup. exuv., 17.VI.64; 1 pup. exuv., 20.VI.64; 1 l a r v . , 1.IV.64; 2 l a r v . ,  15.IV.64;  1 l a r v . , 13.V.64, Marion Lake, B.C.  Cryptochironomus s p . B T h i s s p e c i e s was not r e a r e d but the l a r v a i s almost certainly correctly associated.  The a d u l t male keys t o C.  b l a r i n a Townes i n Townes (1945),but t h e l a r v a and pupa a r e more s i m i l a r t o those o f C. s o r e x Townes ( C u r r y , 1958). Male imago:-- abdomen and l e g s g r e e n i s h ; t h o r a x brownish orange; antenna i n c l u d i n g p e d i c e l brown. 3.31,  Antenna: A.R. 2.75-  mean 3 . 1 9 ( 4 ) , f l a g e l l u m w i t h 11 segments.  Head: p a l p  p r o p o r t i o n s 7.5:20.5:17:20; c l y p e u s w i t h 19-23 b r i s t l e s ;  95 f r o n t a l t u b e r c l e s about t w i c e as l o n g as broad; t e m p o r a l h a i r s i n two o r more i r r e g u l a r rows which extend m e d i a l l y s l i g h t l y p a s t the v e r t e x angles o f eyes. c e n t r a l b r i s t l e s mostly  Thorax:  i n a s i n g l e i r r e g u l a r row; s u p r a -  a l a r b r i s t l e s 6-8 i n a s i n g l e row; s c u t e l l u m w i t h arranged  dorso-  bristles  i n two t r a n s v e r s e rows except m e d i a l l y where t h e r e  may be r u d i m e n t s o f a t h i r d row.  Legs: L.R. 1.35-1.45,  mean 1.41(3); i n n e r apex o f t i b i a w i t h a rounded s c a l e ; t a r s a l beard absent; m i d d l e t i b i a l combs s e p a r a t e , each w i t h a s h o r t s p i n e ; h i n d t i b i a l combs s i m i l a r t o those on m i d d l e tibia.  Wing: l e n g t h 3.1-3.5 mm.;  R, R^ and o u t e r h a l f o f  ^4+5 w i t h m a c r o t r i c h i a ; the o t h e r membrane v e i n s and wing membrane w i t h o u t m a c r o t r i c h i a ; R^ and R2+3 w e l l s e p a r a t e d a t tip;  c u b i t a l f o r k s l i g h t l y beyond r-m.  Hypopygium: ( F i g .  13-K); a n a l p o i n t v e r y l o n g and narrow; s u p e r i o r appendage about as l o n g as broad and covered  with microtrichia;  i n f e r i o r appendage s l i g h t l y s h o r t e r than s u p e r i o r appendage, w i t h about 3 t e r m i n a l b r i s t l e s ; c o x i t e s h o r t and broad. P u p a : — l e n g t h 7.5-8.3 mm.  C e p h a l i c t u b e r c l e : ( F i g . 13-L);  l o n g c o n i c a l and w i t h a s h o r t p r e a p i c a l s p i n e . organ f i l a m e n t o u s .  Respiratory  Abdomen: t e r g i t e I and I I w i t h f i n e  shagreen on t h e a n t e r i o r and c e n t r a l p a r t o f d i s c and a f a i n t honeycombed p a t t e r n on c a u d a l p a r t o f d i s c ; margin o f t e r g i t e I I w i t h a band o f c o a r s e s p i n e s ; III  caudal tergites  t o V ( F i g . 13-M) s i m i l a r t o a n t e r i o r t e r g i t e s but w i t h  a s i n g l e row o f c o a r s e b r i s t l e s a l o n g c a u d a l margin;  96 t e r g i t e VI w i t h o u t honeycomb markings; t e r g i t e V I I w i t h a c a u d a l row o f s p i n e s and shagreen much reduced; t e r g i t e V I I I w i t h a s m a l l p a t c h o f shagreen near each caudol a t e r a l margin and w i t h o u t  a comb o r s p u r ; l a t e r a l f i l a m e n t s  on segments V - V I I I 4-4-4-5; segment I X w i t h a c o n s p i c u o u s two pronged t e r m i n a l p r o j e c t i o n ( F i g . 13-N); a n a l f i n s  each  w i t h 56-81 m a r g i n a l f i l a m e n t s . Larva:—  r e d , maximum l e n g t h 10 mm.  Antenna: ( F i g . 13-0);  a n t e n n a l p r o p o r t i o n s 28:13:14:1.5:1.5; s e n s o r i u m on d i s t a l 2/5 o f b a s a l segment and a n t e n n a l b l a d e a t t a c h e d h a l f of segment 2.  to d i s t a l  Head: l e n g t h 0.47-0.48 mm.(2) e y e s p o t s  s e p a r a t e , d o r s a l eyespot a n t e r i o r o f v e n t r a l one; l a b i a l p l a t e ( F i g . 13-P) w i t h a c l e a r rounded c e n t r a l area o f 5 p a i r s o f l a t e r a l t e e t h , w i d t h of c l e a r a r e a 3.5-3.6  times  i n t o w i d t h o f l a b i a l p l a t e ; mandible ( F i g . 13-Q) w i t h a l o n g d a r k a p i c a l t o o t h and 2 d a r k l a t e r a l s . papilla  Abdomen: a n a l  about as l o n g as b r o a d , w i t h 7 o r 8 t e r m i n a l  bristles;  a n a l g i l l s about 3 times as l o n g as w i d t h at  base, d o r s a l p a i r t e r m i n a t i n g i n a d u l l p o i n t and v e n t r a l p a i r rounded. Ecology:— metres.  B e n t h i c l a r v a e were common a t depths o f 0.5-3.5 I n 1964 most o f t h e emergence took p l a c e i n J u l y ,  but i t d i d c o n t i n u e a t a reduced r a t e u n t i l l a t e August. M a t e r i a l examined:-- lo", 8.VII.64; 1°", 1 9 . V I I I . 6 4 ; ?.VIII.64;  2**,  1 pup. exuv., 8.VII.64; 1 pup. exuv., 11.VII.64;  97 1 pup. exuv., 15.VII.64; 2 pup. exuv., 22.VII.64; 2 l a r v . , 24.VI.64, M a r i o n Lake,  B.C.  Genus HARNISCHIA K i e f f e r H a r n i s c h i a K i e f f e r , 1921, B u l l . Soc. H i s t . n a t . M o s e l l e . 29:69 H a r n i s c h i a Townes, 1945, Am.  M i d i . Nat. 34:147  Four s p e c i e s a r e known t o o c c u r i n Marion Lake.  Harnischia Harnischia  (Cladopelma) g a l a p t e r a Townes  (Cladopelma) g a l a p t e r a Townes, 1945, Am.  Midi.  Nat. 34:148-149 T h i s s p e c i e s was not r e a r e d and the l a r v a i s o n l y tentatively associated.  The a d u l t male agrees w e l l w i t h  Townes d e s c r i p t i o n , but the l a r v a and pupa have not p r e v i o u s l y been d e s c r i b e d . Male imago:-- abdomen and l e g s brown; t h o r a x b l a c k i s h brown; antennal  f l a g e l l u m brown, p e d i c e l b l a c k ; eyes r e d d i s h .  Antenna: A.R.  2.33-2.47(2), f l a g e l l u m w i t h 11  segments.  Head: p a l p p r o p o r t i o n s 7:18:20:25; c l y p e u s w i t h 14 o r 15 b r i s t l e s ; f r o n t a l t u b e r c l e s about 3 t i m e s as l o n g as b r o a d ; t e m p o r a l h a i r s i n s i n g l e rows which extend m e d i a l l y p a s t v e r t e x a n g l e s of e y e s .  Thorax: d o r s o - c e n t r a l  slightly bristles  98 i n a s i n g l e i r r e g u l a r row; s u p r a - a l a r b r i s t l e s 5-6 i n a s i n g l e row; s c u t e l l u m w i t h two t r a n s v e r s e rows o f b r i s t l e s m e d i a l l y and one row l a t e r a l l y .  Wing: l e n g t h 3.3-3.4  mm.;  R, R i and o u t e r 2/3 o f R 4 5 w i t h a row o f m a c r o t r i c h i a ; +  o t h e r membrane v e i n s and wing membrane w i t h o u t R^ and R2+3 n a r r o w l y r-m.  separated  macrotrichia;  a t t i p ; c u b i t a l f o r k beyond  Legs: L.R. 1.45(1); i n n e r apex o f f o r e t i b i a w i t h a  low rounded s c a l e ; f o r e t a r s a l beard s p a r s e o r absent; a p i c a l combs on each m i d d l e and h i n d t i b i a f u s e d and w i t h 2 short spines.  Hypopygium: ( F i g . 12-A); s u p e r i o r appendage  f u s e d t o i n f e r i o r appendage and covered w i t h m i c r o t r i c h i a ; i n f e r i o r appendage s h o r t , broad and covered w i t h t r i c h i a ; c o x i t e and s t y l e  micro-  ankylosed.  P u p a : — l e n g t h 7.5-8.1 mm.(2).  Cephalic tubercle: (Fig.  12-B); cone shaped, a p p a r e n t l y w i t h o u t  a p r e a p i c a l spine.  R e s p i r a t o r y organ: f i l a m e n t o u s w i t h a t l e a s t 5 main branches. Abdomen: t e r g i t e I not shagreened; t e r g i t e I I c a u d a l 1/3 of d i s c shagreened; t e r g i t e s I I I - V I w i t h shagreen on c e n t r a l and  c a u d a l p a r t o f d i s c ; t e r g i t e V I I w i t h f a i n t shagreen  near a n t e r i o r margin and t e r g i t e V I I I w i t h o u t  shagreen;  comb on c a u d o - l a t e r a l margin o f segment V I I I w i t h 3-8 s p i n e s ( F i g . 12-C); l a t e r a l f i l a m e n t s on segments V - V I I I 4-4-4-5; a n a l l o b e s each w i t h 71-80 m a r g i n a l f i l a m e n t s . Larva:—  body r o b u s t , 8 mm. l o n g .  Antenna: ( F i g . 12-D);  about 0.22 mm. l o n g ; a n t e n n a l p r o p o r t i o n s  53:16:4:5:2;  99 s e n s o r i u m on b a s a l 2/5  of f i r s t segment and  e x t e n d s t o m i d d l e of segment 3. spots separate  antennal  Head: l e n g t h 0.38  blade  mm.;  and 3 i n number; l a b i a l p l a t e ( F i g .  12-E)  l i g h t i n c o l o r w i t h 15 even t e e t h , the o u t e r p a i r of a l s are l i g h t l y pigmented and p l a t e ( F i g . 12-E)  eye-  later-  are b i f u r c a t e ; p a r a l a b i a l  w i t h a d e f i n i t e median e x t e n s i o n , a n t e r i o r  margin c r e n u l a t e ; m a x i l l a r y p a l p u s  about t w i c e as l o n g  as  b r o a d ; mandible w i t h a prominent d a r k a p i c a l t o o t h and dark pointed l a t e r a l s . wide, w i t h 8 a p i c a l Ecology:--  3  Abdomen: a n a l p a p i l l a not as l o n g  as  bristles.  T h i s i s a r a r e s p e c i e s i n M a r i o n Lake.  Emerging  a d u l t s were c o l l e c t e d d u r i n g August i n emergence t r a p s s e t o v e r d e p t h s of 1.1-6.0 m e t r e s . M a t e r i a l e x a m i n e d : — l o " , 14. VI11.64; l o " , 19. VI11.64; 2 exuv., ? . V I I I . 6 4 ;  1 l a r v . , 8.VIII.63,  Marion Lake,  pup.  B.C.  H a r n i s c h i a (Cladopelma) alphaeus S u b l e t t e Tendipes (Cryptochironomus) alphaeus S u b l e t t e , 1960, U.S.  n a t n . Mus.  112:222-223  T h i s s p e c i e s was tentatively associated. a higher antennal  Proc.  not r e a r e d and  The  the l a r v a i s o n l y  a d u l t males are l a r g e r and  have  r a t i o than those d e s c r i b e d by S u b l e t t e , but  i n o t h e r r e s p e c t s they are s i m i l a r . i d e n t i c a l w i t h t h a t o f H.  The  pupa i s almost  g a l a p t e r a (page 97)  and  the  very  100  u n u s u a l l a r v a t h a t has been t e n t a t i v e l y p l a c e d h e r e c o u l d not be  identified.  Male i m a g o : — a n t e n n a , p a l p s and l e g s brown; t h o r a x b l a c k ; abdomen g r e e n i s h brown. f l a g e l l u m w i t h 11 segments.  brownish  Antenna: A.R. 2.53-2.59(2),  Head: p a l p p r o p o r t i o n s 6:16:17.5:  22; c l y p e u s w i t h 16-17 b r i s t l e s ; f r o n t a l t u b e r c l e s about t w i c e as l o n g as b r o a d ; t e m p o r a l h a i r s m o s t l y  i n single irreg-  u l a r rows w h i c h e x t e n d m e d i a l l y as f a r as v e r t e x a n g l e s o f eyes.  Thorax: d o r s o - c e n t r a l b r i s t l e s i n a s i n g l e row; s u p r a -  a l a r b r i s t l e s 3-5 i n a s i n g l e row; w i t h one t r a n s v e r s e row o f b r i s t l e s p l u s a few a d d i t i o n a l b r i s t l e s near t h e mid l i n e o f thorax.  Wing: l e n g t h 2.6-2.7 mm.;  ^4+5 with  R, R^ and o u t e r h a l f o f  m a c r o t r i c h i a , o t h e r membrane v e i n s and wing mem-  brane w i t h o u t  m a c r o t r i c h i a ; R^ and R 2 3 n a r r o w l y +  t i p s ; c u b i t a l f o r k below o r s l i g h t l y beyond r-m.  separated at Legs: L.R.  1.65(1); i n n e r apex o f f o r e t i b i a w i t h a low rounded s c a l e ; fore tarsus without hind t i b i a fused. widest  Hypopygium: ( F i g . 12-G); a n a l p o i n t  long,  a t t i p and t a p e r i n g t o a n a r r o w e r base; s u p e r i o r  appendage e n l a r g e d and  a b e a r d ; a p i c a l combs on each m i d d l e and  covered  a t apex; i n f e r i o r appendage low; rounded  w i t h m i c r o t r i c h i a ; c o x i t e and s t y l e  anklosed.  P u p a : — v e r y s i m i l a r t o t h a t o f H. g a l a p t e r a (page 97) but with the f o l l o w i n g d i f f e r e n c e s .  The l e n g t h s o f t h e two  specimens a v a i l a b l e were 6.5 and 7.0 mm. and each a n a l had  66-74 m a r g i n a l  filaments.  lobe  101 Larva:—  body r o b u s t , l e n g t h 7.0 mm.  a n t e n n a l p r o p o r t i o n s 18:6:5:4:2.  Antenna: ( F i g . 12-H);  Head: l e n g t h 0.40-0.45(2);  eyespots i n v e r t i c a l plane, contiguous  o r nearly so; l a b i a l  p l a t e ( F i g . 12-1) w i t h 13 dark t e e t h , f i r s t  l a t e r a l s minute,  second l a t e r a l s b i f i d ; p a r a l a b i a l p l a t e s ( F i g . 12-1) l o n g and s t r i a t e , s e p a r a t e d  i n median a r e a by w i d t h o f median  t o o t h o f l a b i a l p l a t e , median angle o f each p a r a l a b i a l plate with a short spine.  Mandible: ( F i g . 12-J); w i t h a  v e r y l a r g e d a r k a p i c a l t o o t h , two minute p a l e l a t e r a l s and a long accessory  t o o t h ; m a x i l l a r y palpus c o n s t r i c t e d at  base, l e n g t h e q u a l t o g r e a t e s t w i d t h .  Abdomen: a n a l p a p i l l a  about h a l f as l o n g as wide, w i t h 8 a p i c a l b r i s t l e s and two smaller l a t e r a l b r i s t l e s ; anal g i l l s  ( F i g . 12-K) l a r g e and  rounded a p i c a l l y , about as l o n g as p o s t e r i o r p r o l e g s . Ecology:—  T h i s i s a r a r e s p e c i e s i n Marion Lake.  I n 1964  a d u l t s were c o l l e c t e d d u r i n g May and June o v e r depths o f 1.0-6.0 metres. M a t e r i a l e x a m i n e d : — 2 Co; 8.VI.64; lo" pup., 27.V.64; 1 pup. exuv., 8.VI.64; 1 l a r v . ? , 1.VII.64; 1 l a r v . ? , 24.VI.64; 1 l a r v . ? , 2.IX.64, Marion L a k e , B.C.  . H a r n i s c h i a ( H a r n i s c h i a ) p o t a m o g e t i Townes H a r n i s c h i a ( H a r n i s c h i a ) p o t a m o g e t i Townes, 1945, Am. M i d i . Nat. 34:159-160  102  T h i s s p e c i e s was not r e a r e d and the l a r v a i s o n l y tentatively associated. but o t h e r w i s e and  The a d u l t male i s s l i g h t l y  agrees w e l l w i t h Townes d e s c r i p t i o n .  smaller The pupa  l a r v a o f t h i s s p e c i e s have not p r e v i o u s l y been d e s c r i b e d .  Male i m a g o : — a n t e n n a l f l a g e l l u m brown p e d i c e l browni s h orange; t h o r a x brownish orange; abdomen green a n t e r i o r l y and becoming browner towards t h e c a u d a l end.  Antenna: A.R.  2.07-2.50, mean 2 . 2 7 ( 3 ) , f l a g e l l u m w i t h 11 segments.  Head:  p a l p p r o p o r t i o n s 5:14:15:18; c l y p e u s w i t h 16-19 b r i s t l e s ; t e m p o r a l h a i r s i n double i r r e g u l a r rows which extend m e d i a l l y as f a r as v e r t e x a n g l e s o f eyes.  Thorax: d o r s o - c e n t r a l  b r i s t l e s i n an i r r e g u l a r double row a n t e r i o r l y and a s i n g l e row p o s t e r i o r l y ; s u p r a - a l a r b r i s t l e s 5-7 i n a s i n g l e row; s c u t e l l u m w i t h 2 t r a n s v e r s e rows o f b r i s t l e s .  Wing: l e n g t h  2.05-2.20; R, R-^ and R 4 5 w i t h m a c r o t r i c h i a ; a p i c a l 1/3 o f +  wing membrane w i t h s c a t t e r e d m a c r o t r i c h i a ; t i p s o f R i and R  2+3 n a r r o w l y  r-m.  but d i s t i n c t l y s e p a r a t e d ;  c u b i t a l f o r k beyond  Legs: L.R. 1.62(2) i n n e r apex o f f o r e t i b i a w i t h a low  rounded s c a l e ; f o r e t a r s u s w i t h o u t  a b e a r d ; combs on each  m i d d l e and h i n d t i b i a f u s e d , w i t h two medium l e n g t h about 0.02 mm.  long.  spurs  Hypopygium: ( F i g . 12-L); a n a l p o i n t  l o n g and narrow; s u p e r i o r appendage m o d e r a t e l y l o n g ,  without  m i c r o t r i c h i a and a p i c a l l y w i t h two s m a l l b r i s t l e s ; s t y l e and c o x i t e ankylosed, body.  s t y l e l o n g and curved  toward mid l i n e o f  103 P u p a : — l e n g t h 4.6-4.9(4).  C e p h a l i c t u b e r c l e s h o r t and  obtuse, with a p r e a p i c a l b r i s t l e . mentous. III  R e s p i r a t o r y organ  fila-  Abdomen: t e r g i t e s I and I I not shagreened; t e r g i t e  shagreened on t h e p o s t e r i o r 1/4 o f d i s c ; t e r g i t e s IV-VI  (Fig.  12-M) w i t h c e n t r a l and c a u d a l p a r t o f d i s c shagreened;  t e r g i t e s V I I and V I I I w i t h shagreen o n l y on t h e c e n t r a l p a r t of d i s c ; c a u d o - l a t e r a l margin o f segment V I I I w i t h o u t  a comb  o r s p u r ; l a t e r a l f i l a m e n t s on segments V - V I I I 4-4-4-4 o r 4-4-4-5; a n a l f i n s each w i t h 87-111 m a r g i n a l f i l a m e n t s . Larva:—  g r e e n i s h o r w h i t i s h , l e n g t h 7 mm.  Antenna: ( F i g .  12-N); f o u r segmented and mounted on wide prominent t u b e r c l e s ; a n t e n n a l p r o p o r t i o n s 27:12:2:2; s e n s o r i u m on b a s a l 1/5 o f segment 1.  Head: l e n g t h 0.45 mm.;  rowly separated,  e y e s p o t s ( F i g . 12-0) n a r -  d o r s a l eyespot e l o n g a t e and a n t e r i o r o f  v e n t r a l one; l a b i a l p l a t e ( F i g . 12-P), middle t e e t h t r u n c a t e d and outermost l a t e r a l s e l o n g a t e , p o i n t e d , and l i g h t e r i n c o l o r ; p a r a l a b i a l p l a t e ( F i g . 12-P) i n n e r angle extends o n l y to  the f i f t h  l a t e r a l o f t h e l a b i a l p l a t e ; mandible ( F i g . 12-Q)  w i t h a l i g h t a p i c a l t o o t h and 3 l i g h t l a t e r a l t e e t h , t h e two o u t e r l a t e r a l t e e t h a r e t r u n c a t e d and t h e b a s a l one i s p o i n t e d ; premandible ( F i g . 12-R) w i t h 5 d a r k t e e t h .  Abdomen:  a n a l p a p i l l a about as l o n g as broad; a n a l g i l l s l o s t from specimen; p o s t e r i o r p r o l e g s 2.3 times as l o n g as w i d t h a t base. Ecology:—  T h i s i s a r a r e t o common s p e c i e s i n Marion Lake.  104 I n 1964 a d u l t s were t a k e n d u r i n g September and e a r l y O c t o b e r i n emergence  t r a p s s e t o v e r depths o f 0.5-3.5 metres.  M a t e r i a l e x a m i n e d : — 30*0; 19.IX.64; 1 pup., 2 2 . V I I I . 6 4 ; 2 pup. exuv., 19.IX.64; 1 pup. exuv., 29.IX.64; 1 l a r v . , 27.V.64, M a r i o n Lake, B.C.  H a r n i s c h i a ( H a r n i s c h i a ) amachaerus Townes H a r n i s c h i a ( H a r n i s c h i a ) amachaerus Townes, 1945, Am.  Midi.  Nat. 34:168 T h i s s p e c i e s was not r e a r e d , but the l a r v a i s almost c e r t a i n l y c o r r e c t l y a s s o c i a t e d .  The a d u l t male i s  v e r y s i m i l a r t o t h o s e d e s c r i b e d by Townes (1945) and the pupa i s s i m i l a r t o the pupa o f H. amachaerus d e s c r i b e d by Roback (1957).  The median t e e t h o f t h e l a r v a l l a b i a l p l a t e a r e  l e s s p o i n t e d t h a n t h o s e of H. amarchaerus but o t h e r w i s e are very  similar.  Male i m a g o : —  antenna i n c l u d i n g p e d i c e l s brown;  thorax  b r o w n i s h orange; abdomen and l e g s brownish g r e e n . A.R.  1.92-2.09(2), f l a g e l l u m w i t h 11 segments.  Antenna:  Head: p a l p  p r o p o r t i o n s 3:9:10:16; c l y p e u s w i t h 10-12 b r i s t l e s , t e m p o r a l h a i r s i n s i n g l e i r r e g u l a r rows which e x t e n d t o p o i n t s midway between the v e r t e x a n g l e s o f eyes and mid l i n e o f head. Thorax: pronotum p r o j e c t s t o o r s l i g h t l y beyond mesoscutum; d o r s o - c e n t r a l b r i s t l e s i n a s i n g l e i r r e g u l a r row; s u p r a - a l a r  105 b r i s t l e s 4-5  i n a s i n g l e row;  i n a s i n g l e t r a n s v e r s e row.  s c u t e l l u m w i t h about 4 b r i s t l e s Wing: l e n g t h 1.65-1.70 mm.;  R  and R i w i t h o u t o r w i t h w i d e l y s c a t t e r e d m a c r o t r i c h i a ; wing membrane w i t h o u t m a c r o t r i c h i a ; R and R^ n a r r o w l y at t i p s ; c u b i t a l f o r k beyond r-m; about 9 h a i r s .  Legs: L.R.  separated  squama w i t h a f r i n g e of  1.67-1.74; i n n e r apex of f o r e  t i b i a w i t h a low rounded s c a l e ; f o r e t a r s u s w i t h o u t  a beard;  a p i c a l combs of each m i d d l e and h i n d t i b i a f u s e d , w i t h  two  short spines.  and  Hypopygium: ( F i g . 12-S)  anal point long  narrow; s u p e r i o r appendage v e r y s h o r t , w i t h 1-2 d i r e c t e d b r i s t l e s near apex; c o x i t e and s t y l e s t y l e l o n g and curved  ankylosed,  inward.  P u p a : — l e n g t h 3.9-4.2 mm.(4).  Cephalic tubercle ( F i g .  c o n i c a l with a long p r e a p i c a l b r i s t l e .  Abdomen: t e r -  I I w i t h o u t shagreen, row of hooks at  margin of t e r g i t e I I d i v i d e d at mid  12-T)  R e s p i r a t o r y organ:  f i l a m e n t o u s , w i t h at l e a s t 3 main b r a n c h e s . g i t e s I and  inward  caudal  l i n e ; t e r g i t e s I I I - V each  w i t h p a i r e d r e c t a n g u l a r p a t c h e s of c o a r s e s p i n u l e s near the c a u d a l margin of d i s c ( F i g . 12-U); t e r g i t e VI w i t h a median o v a l p a t c h of c o a r s e s p i n e s near the c a u d a l margin of d i s c ( F i g . 12-V); t e r g i t e s V I I and V I I I not shagreened;  lateral  f i l a m e n t s on segments V - V I I I 4-4-4-4;;spur on c a u d o - l a t e r a l margin of segment V I I s i m p l e  ( F i g . 12-W); a n a l l o b e s each  w i t h 28-37 m a r g i n a l f i l a m e n t s .  106 L a r v a : — r e d , maximum l e n g t h 6 mm.  Antenna:  ( F i g . 12-X);  a n t e n n a l p r o p o r t i o n s 25:12:1:2:1; s e n s o r i u m on b a s a l 1/3 segment 1. 12-Y)  of  Head: l e n g t h 0.27-0.32 mm.(5); e y e s p o t s ( F i g .  s e p a r a t e d ; l a b i a l p l a t e ( F i g . 12-Z) w i t h a b i f i d median  t o o t h and 6 p a i r s of l a t e r a l s , the s i x t h l a t e r a l i s v e r y l a r g e and o f t e n weakly notched; mandible moderately l o n g a p i c a l premandible  ( F i g . 12-AA) w i t h a  t o o t h and 2 t r u n c a t e d l a t e r a l t e e t h ;  ( F i g . 12-BB) b i f i d , o u t e r t o o t h much the n a r -  r o w e s t ; m a x i l l a r y p a l p u s as l o n g as o r l o n g e r than wide. Abdomen: a n a l p a p i l l a about as l o n g as broad; a n a l g i l l s about 2/3  as l o n g as p o s t e r i o r p r o l e g s , a p i c a l l y rounded  or  ending i n a d u l l p o i n t . E c o l o g y : — B e n t h i c l a r v a e were common at depths of 0.5-1.5 metres.  I n 1964 the a d u l t s emerged from mid J u l y u n t i l mid  August. M a t e r i a l e x a m i n e d : — 20*0; 1 0 . V I I I . 6 4 ; 1 pup.,  1.VIII.64; 1  pup. exuv., 1 . V I I I . 6 4 ; 2 pup. exuv., 1 0 . V I I I . 6 4 ; 2 22.VII.64; Lake,  larv.,  1 l a r v . , 5 . V I I I . 6 4 ; 2 l a r v . , ? . V I I I . 6 4 , Marion  B.C.  Genus PAGASTIELLA B r u n d i n Pagastiella  B r u n d i n , 1949, Rep.  I n s t . Freshwat. Res. D r o t -  t n i n g h o l m . 30:840-841 One  s p e c i e s o c c u r s i n Marion Lake.  107  P a g a s t i e l l a sp. A T h i s s p e c i e s was  r e a r e d and so f a r as i s known i t  i s the f i r s t North American r e c o r d of the genus.  The  adult  male resembles t h a t of P. o r o p h i l a (Edwards), but has h a i r s on the squama r a t h e r than 0-3. than t h a t d e s c r i b e d by B r u n d i n  3-5  The pupa i s l a r g e r  (1949) and  p l a t e has a minute p a i r of rounded f i r s t  the l a r v a l  labial  l a t e r a l s which are  absent i n B r u n d i n ' s specimens. Male i m a g o : — t h o r a x b l a c k , abdomen and Antenna: A.R.  l e g s brownish b l a c k .  1.47-1.53, mean 1.51(3), f l a g e l l u m w i t h  segments.  Head: p a l p p r o p o r t i o n s 4:8:10:13; c l y p e u s  w i t h 13-15  h a i r s ; v e r t e x a n g l e s of eyes s e p a r a t e d  a n o t h e r by about 1/3  13 small  from  one  the w i d t h of head; t e m p o r a l h a i r s i n  s i n g l e rows which extend m e d i a l l y to p o i n t s about mid between v e r t e x a n g l e s of eyes and the mid  way  l i n e of head.  Wing: ( F i g . 21-H); l e n g t h 1.90-1.95 mm.(4); wing membrane and membrane v e i n s w i t h o u t m a c r o t r i c h i a ; squama w i t h hairs.  Legs: L.R.  1.09-1.20: f o r e t a r s u s w i t h o u t  3-5  a beard;  t i b i a l comb on each m i d d l e and h i n d l e g v e r y s h o r t , w i t h o r r a r e l y 2 l o n g s p u r s t h a t u s u a l l y are s e p a r a t e d main body of the comb; p u l v i l l i end of c l a w s .  one  from the  l o n g , r e a c h i n g almost to  Hypopygium: ( F i g . 14-A); a n a l p o i n t l o n g ,  and curved downward; s u p e r i o r appendage s m a l l ,  curved  a p i c a l l y and w i t h a l o n g l a t e r a l s p i n e near base; i n f e r i o r appendage narrow, e x t e n d i n g  about as f a r p o s t e r i o r l y as a n a l  108  p o i n t ; s t y l e l o n g and narrow. P u p a : — l e n g t h 3.6-4.1 mm.(4).  Cephalic tubercle: ( F i g .  14-B); l o n g t r u n c a t e d a p i c a l l y and w i t h a l o n g t e r m i n a l bristle. branches.  R e s p i r a t o r y organ: w i t h a t l e a s t 4 l o n g  filamentous  Abdomen: t e r g i t e s I and I I not shagreened; t e r -  g i t e s I I I - V I w i t h an a n t e r i o r and a p o s t e r i o r band o f s p i n u les  ( F i g . 14-C), and on t e r g i t e s V and VI these bands a r e  connected by a median p a t c h o f f i n e s p i n u l e s ; t e r g i t e V I I w i t h an a n t e r i o r t r a n s v e r s e band o f s p i n u l e s and t e r g i t e VIII without  shagreen; l a t e r a l f i l a m e n t s on segments V - V I I I  u s u a l l y 3-3-4-5; comb a t c a u d o - l a t e r a l margin o f segment V I I I w i t h 1-3 s e p a r a t e o r n e a r l y s e p a r a t e  coarse spines ( F i g .  14-D); a n a l l o b e s each w i t h 13-15 m a r g i n a l f i l a m e n t s . Larva:—  p a l e r e d , maximum l e n g t h 5.0 mm.  14-E); l e n g t h about 0.07 mm.; 2:1;  Antenna: ( F i g .  a n t e n n a l p r o p o r t i o n s 18:4:1:  s e n s o r i u m on b a s a l 1/3 o f f i r s t segment and a n t e n n a l  b l a d e about 1.3 times as l o n g as segments 2-5 combined. Head: l e n g t h 0.21-0.22 mm.(4); e y e s p o t s ( F i g . 14-F) s m a l l and w i d e l y s e p a r a t e d ;  l a b i a l p l a t e ( F i g . 14-G) almost t r a n s -  p a r e n t w i t h a l a r g e b i f i d median t o o t h and 7 p a i r s o f l a t e r a l s , the f i r s t  l a t e r a l s a r e low and rounded, t h e second  l a t e r a l s a r e v e r y broad and t r u n c a t e d ; mandible ( F i g . 14-H) w i t h a l o n g p a l e a p i c a l t o o t h , 4 o r 5 p a l e l a t e r a l s and 2 p a l e d o r s o - m e s a l t e e t h ; m a x i l l a r y p a l p u s about t w i c e as l o n g as b r o a d .  Abdomen:, p o s t e r i o r segments d i s t i n c t l y  thinner  109 t h a n a n t e r i o r ones; a n a l p a p i l l a s m a l l and not as l o n g as b r o a d ; a n a l g i l l s about h a l f as l o n g as p o s t e r i o r p r o l e g s , rounded a p i c a l l y and about f o u r t i m e s as l o n g as b r o a d . E c o l o g y : — B e n t h i c l a r v a e were abundant at depths from 0.54.5 metres.  In M a r i o n Lake t h i s s p e c i e s has a two y e a r l i f e  c y c l e and i n 1964 a d u l t emergence  took p l a c e f r o m the l a s t  week i n May u n t i l the end of J u l y . M a t e r i a l e x a m i n e d : — 40*0", 31.V.64; 1 pup. exuv., 28.V.64; 3 pup. exuv., 31.V.64; 1 pup. exuv., 1.VI.64; 1 pup. exuv., 10.VI.64; 4 l a r v . , 15.IV.64, M a r i o n Lake, B.C.  Genus MICROTENDIPES K i e f f e r Microtendipes  K i e f f e r , 1915, B r o t e r i a 13:70  Microtendipes  Townes, 1945, Am. M i d i . Nat. 34:22-23  One s p e c i e s o c c u r s i n M a r i o n Lake.  Microtendipes  p e d e l l u s (De Geer)  T i p u l a p e d e l l a De Geer, 1776, Me'm.  p. S e r v i r a l ' H i s t . d.  I n s e c t a 6:379 Microtendipes  p e d e l l u s Townes, 1945, Am.  T h i s s p e c i e s was r e a r e d .  The M a r i o n Lake a d u l t  males a r e l a r g e r (wing l e n g t h 4.0-4.6 mm. mm.)  M i d i . Nat. 34:24-26  and have a h i g h e r a n t e n n a l r a t i o  compared t o 3.7  (3.41-3.93 compared t o  110  2.8)  than the a d u l t s d e s c r i b e d by Townes (1945).  The  color  resembles t h a t of M. p e d e l l u s v a r . s t y g i u s Townes but  the  d i f f e r e n c e s i n s i z e and a n t e n n a l r a t i o a l o n g w i t h the f a c t t h a t the M a r i o n Lake male imagos have a t a r s a l beard would suggest t h a t t h i s i s a new The  v a r i e t y i f not a new  species.  l a r v a and pupa are b o t h s i m i l a r t o but tend t o be l a r g e r  than those of M.  pedellus.  Male i m a g o : — antenna and abdomen b l a c k .  l e g s brownish b l a c k , t h o r a x  Antenna: A.R.  f l a g e l l u m w i t h 13 segments.  and  3.41-3.93, mean 3 . 6 3 ( 3 ) , Head: p a l p p r o p o r t i o n s 8:31:29:  38; c l y p e u s w i t h 27-40 b r i s t l e s ; v e r t e x a n g l e s of eyes separated  by about 1/4  the w i d t h of head; t e m p o r a l h a i r s  a n t e r i o r l y i n 3 o r 4 i r r e g u l a r rows and p o s t e r i o r l y i n s i n g l e rows which extend to p o i n t s about mid-way between v e r t e x a n g l e s of eyes and the mid reduced, not e x t e n d i n g  l i n e of head.  Thorax: pronotum  to l e v e l of mesoscutum; a c r o s t i c h i a l  b r i s t l e s absent; d o r s o - c e n t r a l b r i s t l e s i n a s i n g l e i r r e g u l a r row;  s u p r a - a l a r b r i s t l e s 5-8  i n a s i n g l e row;  scutellum  m e d i a l l y w i t h 3 o r 4 t r a n s v e r s e rows of b r i s t l e s and a l l y w i t h 2 t r a n s v e r s e rows. 4.6(6);  Wing: ( F i g . 2 1 - F ) ;  later-  length  4.0-  R and R i w i t h m a c r o t r i c h i a ; wing membrane w i t h o u t  m a c r o t r i c h i a ; R^ and s l i g h t l y beyond r-m.  R2+3  j o i n e d at t i p s ; c u b i t a l f o r k  Legs: L.R.  1.06-1.19(4); f o r e femur  w i t h a p a t c h of c o a r s e backward d i r e c t e d s p i n e s at a p o i n t about 3/4  of the d i s t a n c e from the base to the apex; t i b i a  Ill  w i t h s e v e r a l c o a r s e h a i r s at apex; t a r s u s w i t h a m o d e r a t e l y heavy b e a r d ; t i b i a l combs on each m i d d l e and h i n d l e g s e p a r a t e d , one w i t h a l o n g curved  s p u r and the o t h e r unarmed.  Hypopygium: ( F i g . 14-1); a n a l p o i n t l o n g and narrow; s u p e r i o r appendage broad, bent s h a r p l y toward mid  l i n e and w i t h  5-10  d o r s o - l a t e r a l b r i s t l e s near bend; c o x i t e l o n g and s t y l u s s h o r t and r a t h e r b r o a d . P u p a : — l e n g t h 7.9-8.6 mm.(4). acute, without  Cephalic t u b e r c l e : long  a preapical bristle.  a t l e a s t 6 main b r a n c h e s .  and  R e s p i r a t o r y organ: w i t h  Abdomen: t e r g i t e I not shagreened;  t e r g i t e I I ( F i g . 14-J) w i t h an a n t e r i o r t r a n s v e r s e band of coarse s p i n u l e s , much of p o s t e r i o r p a r t of d i s c covered  with  f i n e s p i n u l e s but w i t h two c o n s p i c u o u s c l e a r a r e a s near the c a u d a l margin; t e r g i t e s I I I - V w i t h shagreen p a t t e r n s  similar  t o but weaker than t h a t on t e r g i t e I I ; t e r g i t e s VI and V I I I w i t h f a i n t shagreen near the a n t e r i o r and p o s t e r i o r margins; t e r g i t e V I I not shagreened; l a t e r a l f i l a m e n t s on segments V - V I I I 3-4-4-5; comb on c a u d o - l a t e r a l margin of segment V I I I w i t h 2-4  separate or nearly separate  spines  ( F i g . 14-K); a n a l  l o b e s each w i t h 32-42 m a r g i n a l f i l a m e n t s . Larva:—  r e d , maximum l e n g t h 16 mm.  s i x segmented, l e n g t h 0.25  mm.;  5:4:1.5; s e n s o r i u m on b a s a l 2/5  Antenna: ( F i g . 14-L);  a n t e n n a l p r o p o r t i o n s 26:5:6: of segment 1; a n t e n n a l  as l o n g as o r s l i g h t l y l o n g e r than segments 2-6  blade  combined.  Head: l e n g t h 0.54-0.58 mm.(3); e y e s p o t s ( F i g . 14-M)  contiguous  112 o r n e a r l y s o ; l a b i a l p l a t e ( F i g . 14-N) w i t h 14 t e e t h , t h e two median t e e t h p a l e and the o t h e r s d a r k ; mandible ( F i g . 14-0) w i t h a d a r k a p i c a l t o o t h , 3 dark l a t e r a l s and a l i g h t dorso-mesal t o o t h .  Abdomen: a n a l p a p i l l a s l i g h t l y  tapered,  about as l o n g as w i d t h a t base and a p i c a l l y w i t h 8 b r i s t l e s ; a n a l g i l l s about as l o n g as p o s t e r i o r p r o l e g s , t a p e r e d , curved s h a r p l y downward and a p i c a l l y rounded o r e n d i n g i n a d u l l point. E c o l o g y : — T h i s i s a r a r e species i n Marion Lake.  Larvae  were t a k e n a t depths, from 0.5-4.5 metres and i n 1964 emergence  adult  l a s t e d from mid May u n t i l e a r l y J u l y .  M a t e r i a l e x a m i n e d : — 2°*°; 8.V.65; 2 5 7.V.64; 1 pup. exuv., r f c  16.V.64; 1 pup. exuv., 17.V.64; 2 pup. exuv., 27.V.64; 1 l a r v . , 1.IV.64; 2 l a r v . , 15.IV.64, M a r i o n Lake, B.C.  Genus CHIRONOMUS Meigen Chironomus Meigen, 1803, I l l i g e r ' s Mag. 2_:260 Tendipes Townes, 1945, Am. M i d i . Nat. 34:101 Three s p e c i e s are known to o c c u r i n M a r i o n Lake.  Chironomus  (Limnochironomus) modestus Say  Chironomus modestus Say, 1823, J . Acad. n a t . S c i . P h i l a d . 3:13 Tendipes (Limnochironomus) modestus Townes, 1945, Am.  Midi.  113 Nat.  34:106-107  Chironomus ( D i c r o t e n d i p e s ) modestus S u b l e t t e , 1964a, Tulane S t u d . Z o o l . 11(4):126 T h i s s p e c i e s was C. modestus. and  The  r e a r e d and  i s almost c e r t a i n l y  a d u l t keys to C. modestus i n Townes (1945)  the l a r v a and pupa b o t h key to C. modestus i n Roback  (1957) . Male i m a g o : — antenna and  t a r s i brown; abdomen and  femora  green; t h o r a c i c s c l e r i t e s brown, remainder of t h o r a x green. Antenna: A.R.  2.78-2.87(2), f l a g e l l u m w i t h 11 segments.  Head: p a l p p r o p o r t i o n s 7:17.5:19.5:25; c l y p e u s w i t h  18-22  b r i s t l e s ; f r o n t a l t u b e r c l e w i d e s t near apex and about t w i c e as l o n g as g r e a t e s t w i d t h ; t e m p o r a l h a i r s i n s i n g l e rows which almost meet at mid  l i n e of head.  b r i s t l e s i n a s i n g l e row; row; and  s c u t e l l u m w i t h one two rows m e d i a l l y .  Thorax: d o r s o - c e n t r a l  s u p r a - a l a r b r i s t l e s 4-5  in a single  t r a n s v e r s e row of b r i s t l e s  laterally  Wing: l e n g t h 2.3-2.8 mm. (3) ; R,  R-^  and o u t e r h a l f of R 4 5 w i t h a few m a c r o t r i c h i a ; wing membrane +  w i t h o u t m a c r o t r i c h i a ; R^ and R2+3 d i s t i n c t l y s e p a r a t e d t i p s ; c u b i t a l f o r k s l i g h t l y beyond r-m. 1.56;  f o r e tarsus without  Legs: L.R.  at  1.50-  a b e a r d ; t i b i a l combs on each mid-  d l e and h i n d t i b i a s e p a r a t e , each w i t h a s h o r t s p i n e . Hypopygium: ( F i g . 14-P); a n a l p o i n t broad and curved downward; apex of s u p e r i o r appendage e n l a r g e d , about 3 times as wide as the s h a f t and w i t h s e v e r a l s m a l l s p i n e s ; i n f e r i o r appendage  114 v e r y l o n g and narrow w i t h a curved s h a f t and an s p i n e b e a r i n g apex; s t y l e l o n g and curved P u p a : — l e n g t h 5.9-7.0 mm.(8).  enlarged  inward.  Cephalic tubercle: ( F i g .  14-Q); acute w i t h a l o n g b r i s t l e near apex.  Respiratory  o r g a n , f i l a m e n t o u s w i t h about 4 main b r a n c h e s .  Abdomen:  t e r g i t e I not shagreened; t e r g i t e s I I - V I w i t h a c a u d a l band of c o a r s e s p i n u l e s and a c e n t r a l p a t c h of f i n e s p i n u l e s ( F i g . 14-R); t e r g i t e V I I not shagreened and t e r g i t e V I I I w i t h 2 f a i n t l a t e r a l p a t c h e s of shagreen; s t e r n i t e I w i t h a c a u d a l band of v a r i a b l e s p i n u l e s ; s t e r n i t e I I w i t h an i o r and  anter-  a p o s t e r i o r t r a n s v e r s e band of s p i n u l e s ; s t e r n i t e  I I I without  a t r a n s v e r s e band of s p i n u l e s ; l a t e r a l f i l a m e n t s ft  on segments V - V I I I 4-4-4-4; s p u r on c a u d o - l a t e r a l margin of segment V I I I ( F i g . 14-S) i o r accessory  simple, r a r e l y with a small anter-  s p i n e ; a n a l l o b e s each w i t h 45-64 m a r g i n a l  filaments. Larva:—  y e l l o w i s h w i t h a r e d d i s h t i n g e , head of mature  l a r v a w i t h a brown d o r s a l - m e s a l l a r v a 10 mm.  s t r i p e ; maximum l e n g t h of  Antenna: ( F i g . 14-T); about 0.13  mm.  long;  a n t e n n a l p r o p o r t i o n s 26:8:5:7:3; s e n s o r i u m on b a s a l 1/3 segment 1 and 4.  a n t e n n a l b l a d e extends about to end of segment  Head: l e n g t h 0.44-0.57 mm.(5); e y e s p o t s ( F i g .  separate,  of  lower eyespot d i v i d e d o r r a r e l y b i l o b e d ;  p l a t e ( F i g . 14-V) l a r g e s t and may  14-U) labial  w i t h 13 t e e t h , the median t o o t h i s the be weakly t r i l o b e d ; premandible b i f i d ,  outer  115 t o o t h about h a l f as wide as i n n e r one; e p i p h a r y n g e a l comb w i t h 5 s h o r t rounded t e e t h , t h e m i d d l e one l a r g e r and isolated  from n e i g h b o r s ; mandible ( F i g . 14-W)  with a long  dark a p i c a l t o o t h , 3 d a r k l a t e r a l s and a l i g h t d o r s o - m e s a l tooth.  Abdomen: v e n t r a l g i l l s on segment V I I I a b s e n t ; a n a l  p a p i l l a as l o n g as o r l o n g e r t h a n broad and w i t h 8 a p i c a l b r i s t l e s ; a n a l g i l l s rounded a p i c a l l y ,  s l i g h t l y shorter  t h a n p o s t e r i o r p r o l e g s and v e n t r a l p a i r c u r v e d downward. E c o l o g y : — B e n t h i c l a r v a e o c c u r r e d a t d e p t h s o f 0.5-4.5 metres but were commonest a t a d e p t h of about 3.0 metres. T h i s s p e c i e s had a one y e a r l i f e c y c l e and i n 1964 a d u l t emergence  began i n mid May, reached a peak i n e a r l y August  and was o v e r by t h e end o f August. M a t e r i a l e x a m i n e d : — 2 0*0; 2. VI11.64; 1 pup. exuv., 15.V.64; 1 pup. exuv., 17.V.64; 1 pup. exuv., 20.V.64; 1 pup. exuv., 17.VI.64; 4 pup. exuv., 2 . V I I I . 6 4 ; 1 l a r v . , l . I V . 6 4 ; 1 l a r v . , 27.V.64; 2 l a r v . , 24.VI.64; 1 l a r v . , 8.VII.64, M a r i o n Lake,  B.C.  Chironomus  (Chironomus) r e m p e l i i T h i e n .  Chironomus h y p e r b o r e u s Rempel, 1936, J . b i o l . Bd. Can. 2: 209-221 Chironomus r e m p e l i i Thienemann,  1942, A r c h H y d r o b i o l . 17:  233-234 Tendipes a n t h r a c i n u s Townes, 1945, Am.  M i d i . Nat. 34:147-  116 148;  I n p a r t C. r e m p e l i i  Chironomus r e m p e l i i Thienemann, 1954,  Binnengewasser 20:285-  287 T h i s s p e c i e s was  r e a r e d and a l l s t a g e s agree q u i t e  w e l l w i t h those d e s c r i b e d by Rempel (1936).  The  anal point  of the hypopygium i s more rounded and the s e n s o r i u m i s c l o s e r to the base of the l a r v a l antenna than i n Rempel's specimens.  I n a d d i t i o n , C. r e m p e l i i has a two year  life  c y c l e i n Waskesiu Lake, Saskatchewan and  the specimens from  M a r i o n Lake have a one  Other key  year l i f e c y c l e .  charac-  t e r s such as the l a r g e c l y p e u s and bearded f o r e t a r s u s are t y p i c a l of the s p e c i e s .  Townes (1945) has i n c l u d e d Rempel's  specimens i n the s p e c i e s C. a n t h r a c i n u s Z e t t . , but Thienemann considered  them as a s e p a r a t e  species.  Male i m a g o : — b l a c k o r b l a c k i s h w i t h grey bands a l o n g c a u d a l margins of each abdominal t e r g i t e .  Antenna:  the A.R.  5.23-5.58, mean 5.37(4), f l a g e l l u m w i t h 11 segments.  Head:  p a l p p r o p o r t i o n s 8:28:26:34; c l y p e u s l a r g e w i t h 49-62 b r i s t l e s ; f r o n t a l t u b e r c l e s r o d - l i k e and  about 3 times  as  l o n g as b r o a d ; t e m p o r a l h a i r s i n d o u b l e i r r e g u l a r rows which extend m e d i a l l y t o p o i n t s midway between v e r t e x a n g l e s eyes and  the mid  l i n e of head.  Thorax:  dorso-central  b r i s t l e s i n a d o u b l e i r r e g u l a r row;  supra-alar b r i s t l e s  i n a s i n g l e row;  irregular  s c u t e l l u m w i t h two  of  6-9  transverse  rows of b r i s t l e s near the l a t e r a l margins and w i t h randomly  117 p l a c e d b r i s t l e s near t h e mid l i n e o f t h o r a x . 21-G) ; l e n g t h 4.2-4.9 mm.;  Wing: ( F i g .  R, R-^ and o u t e r 1/3 o f R 4  + 5  with  m a c r o t r i c h i a ; wing membrane w i t h o u t m a c r o t r i c h i a ; c u b i t a l f o r k below o r s l i g h t l y beyond r-m.  Legs: L.R. 1.23-1.44(3);  f o r e t a r s u s w i t h a l o n g s p a r s e b e a r d ; t i b i a l combs on each m i d d l e and h i n d l e g s e p a r a t e , each w i t h a s h o r t  spur.  Abdomen: c a u d a l margin o f t e r g i t e s grey and w i t h o u t  hairs.  Hypopygium: ( F i g . 15-A); a n a l p o i n t v e r y b r o a d , t a p e r i n g t o a rounded apex; s u p e r i o r appendage c u r v e d , w i t h o u t t r i c h i a and i n f e r i o r appendage broad and e x t e n d i n g  micropast  anal  point. P u p a : — l e n g t h 11.1-12.0 mm.(7).  Cephalic tubercle: ( F i g .  15-B); acute w i t h a s h o r t b r i s t l e near apex.  Respiratory  organ: f i l a m e n t o u s w i t h a t l e a s t 5 main b r a n c h e s .  Abdomen:  t e r g i t e I not shagreened; t e r g i t e s I I - V I w i t h shagreen on c e n t r a l and c a u d a l p a r t o f d i s c ( F i g . 15-C) ; t e r g i t e V I I w i t h a f i n e p a t c h o f shagreen near each a n t e r o - l a t e r a l angle and t e r g i t e V I I I w i t h two p a t c h e s o f shagreen on the c e n t r a l p a r t o f d i s c ; l a t e r a l f i l a m e n t s on segments V - V I I I u s u a l l y 4-4-4-5; s p u r on c a u d o - l a t e r a l margin o f segment V I I I w i t h 3-8 s p i n e s  ( F i g . 15-D); a n a l l o b e s each w i t h 120-  170+ m a r g i n a l f i l a m e n t s . Larva:—  r e d , maximum l e n g t h 22 mm.  l e n g t h about 0.22 mm.;  Antenna: ( F i g . 15-E);  a n t e n n a l p r o p o r t i o n s 64:17:5:7:3;  s e n s o r i u m on b a s a l 2/5 o f segment 1 and a n t e n n a l  blade  118 extends t o o r n e a r l y t o t i p of segment 5.  Head:  1.32-1.44 mm.(4); e y e s p o t s ( F i g . 15-F) w i d e l y  length  separated,  lower eyespot o f t e n somewhat b i l o b e d ; l a b i a l p l a t e ( F i g . 15-G) w i t h 15 d a r k t e e t h , the next t o the o u t s i d e l o n g e r t h a n a d j a c e n t ones; mandible ( F i g . 15-H) and f i r s t  laterals  apical  tooth  two l a t e r a l t e e t h d a r k , lower l a t e r a l t o o t h and  d o r s o - m e s a l t o o t h l i g h t c o l o r e d , a c c e s s o r y t o o t h c l u b shaped. Abdomen: v e n t r a l g i l l on abdominal segment V I I I s l e n d e r and about 1.5 t i m e s as l o n g as p o s t e r i o r p r o l e g s ; a n a l  papilla  about as l o n g as w i d t h a t base and t e r m i n a t i n g i n 7 f i n e b r i s t l e s ; anal g i l l s  ( F i g . 15-1) l o n g , rounded a p i c a l l y  and  c u r v e d downward. E c o l o g y : — B e n t h i c l a r v a e were common a t d e p t h s o f 4-6 metres.  T h i s s p e c i e s has a one y e a r l i f e c y c l e i n M a r i o n  Lake and i n 1964 a d u l t emergence took p l a c e i n A p r i l ,  May  and June. M a t e r i a l examined:-- 1°", 24.IV.64; 1°", 12.V.64; 1°", 8.VI.64; lo", 7.V.64; 1 pup. exuv., 22.IV.64; 1 pup. exuv., 24.IV.64; 1 pup. exuv., 7.V.64; 2 pup. exuv., 8.VI.64; 1 pup. exuv., 15.VI.64; 1 pup. exuv., 7.V.64; 1 l a r v . , l . I V . 6 4 ; 1 l a r v . , 15.IV.64; 2 l a r v . , 10.VI.64, M a r i o n Lake,  Chironomus  B.C.  (Chironomus) d e c o r u s Johannsen  Chironomus d e c o r u s Johannsen, 1905, B u l l . N.Y. 239.  S t . Mus.  86:  119 Tendipes d e c o r u s Townes, 1945, T h i s s p e c i e s was decorus. (1945) and  The  Am.  M i d i . Nat.  r e a r e d and  34:120-122  i s almost c e r t a i n l y  C.  a d u l t male keys t o t h i s s p e c i e s i n Townes  the immature s t a g e s are v e r y s i m i l a r to  those  d e s c r i b e d by Johannsen (1937b). Male i m a g o : — antennae and p a l p s l i g h t brown; t h o r a c i c s c l e r i t e s brown, remainder of t h o r a x green; femora y e l l o w i s h g r e e n , t i b i a g r e e n i s h brown, t a r s i brown.  Abdomen: t e r g i t e s  I - I I I g r e e n i s h brown a n t e r i o r l y and green p o s t e r i o r l y ,  ter-  g i t e IV g r e e n i s h brown, t e r g i t e s V - V I I I brownish b l a c k a n t e r i o r l y and 3.93,  l i g h t brown p o s t e r i o r l y .  Antenna: A.R.  mean 3 . 5 ( 5 ) , f l a g e l l u m w i t h 11 segments.  3.37-  Head: p a l p  p r o p o r t i o n s 6.5:24:24:32; c l y p e u s w i t h 23-34 b r i s t l e s ; f r o n t a l t u b e r c l e s about 3 times as l o n g as broad; t e m p o r a l h a i r s i n i r r e g u l a r d o u b l e rows which extend m e d i a l l y about as f a r as v e r t e x a n g l e s of eyes.  Thorax: d o r s o - c e n t r a l  b r i s t l e s i n a d o u b l e i r r e g u l a r row; i n a s i n g l e row; bristles.  supra-alar b r i s t l e s  6-9  s c u t e l l u m w i t h 2 t r a n s v e r s e rows of  Wing: l e n g t h 3.8-4.1 mm.(4); R, R^  and at  least  o u t e r h a l f of R4+5 w i t h m a c r o t r i c h i a ; wing membrane w i t h o u t m a c r o t r i c h i a ; c u b i t a l f o r k about d i r e c t l y below r-m. L.R.  1.47-1.57; f o r e t a r s u s w i t h o u t  Legs:  a b e a r d ; t i b i a l combs on  each m i d d l e and h i n d l e g s e p a r a t e , each w i t h a s m a l l  spur.  Hypopygium: ( F i g . 1 5 - J ) ; a n a l p o i n t b r o a d , t a p e r i n g s l i g h t l y t o a rounded apex; s u p e r i o r appendage h o r n shaped and  curved  120 s l i g h t l y inward; far  i n f e r i o r appendage s h o r t not e x t e n d i n g as  p o s t e r i o r l y as a n a l p o i n t .  P u p a : — l e n g t h 9.8-10.5 mm.(2). 15-K)  Cephalic tubercle ( F i g .  acute w i t h a s h o r t b r i s t l e near t i p .  Respiratory  o r g a n : f i l a m e n t o u s w i t h about 4 main b r a n c h e s .  Abdomen:  t e r g i t e I w i t h o u t shagreen; t e r g i t e s I I - V I w i t h shagreen on most o f d i s c ( F i g . 1 5 - L ) , t h e c o a r s e r s p i n e s b e i n g near the c a u d a l margin; t e r g i t e s V I I and V I I I w i t h o u t  shagreen;  l a t e r a l f i l a m e n t s on segments V - V I I I 4-4-4-5; s p u r on caudol a t e r a l margin o f ^segment V I I I w i t h 2-4 s p i n e s ( F i g . 15-M); a n a l l o b e s each w i t h 89-93 f i l a m e n t s . Larva:—  r e d , maximum l e n g t h 17 mm.  about 0.18 mm.  Antenna: ( F i g . 15-N)  l o n g ; a n t e n n a l p r o p o r t i o n s 52:15:4:5:3; sen-  s o r i u m on b a s a l 2/5 o f segment 1 and a n t e n n a l b l a d e to  t i p o f segment 4.  (Fig.  extends  Head: l e n g t h 1.0-1.2 mm.(5); e y e s p o t s  15-0) w i d e l y s e p a r a t e d ,  lower eyespot d i s t i n c t l y  b i l o b e d o r d i v i d e d ; l a b i a l p l a t e s m a l l e r but o t h e r w i s e  very  s i m i l a r t o t h a t o f C. r e m p e l i i ( F i g . 15-G), mandible ( F i g . 15-P)  a p i c a l t o o t h and two upper l a t e r a l s d a r k , lower  e r a l t o o t h and d o r s o - m e s a l t o o t h l i g h t c o l o r e d .  lat-  Abdomen:  v e n t r a l g i l l s on segment VHI as l o n g as o r l o n g e r than p o s t e r i o r p r o l e g s : a n a l p a p i l l a s m a l l , t u b u l a r and w i t h 7 f i n e a p i c a l b r i s t l e s ; anal g i l l s  ( F i g . 15-Q) l e n g t h 3-5  times maximum w i d t h , a p i c a l l y rounded and t h e v e n t r a l ones each w i t h a c o n s p i c u o u s c o n s t r i c t i o n a t base.  121 E c o l o g y : — Benthic  l a r v a e were common a t d e p t h s o f 4-6 metres.  T h i s s p e c i e s had a one y e a r l i f e c y c l e and i n 1964 emergence  adult  l a s t e d f r o m e a r l y A p r i l u n t i l e a r l y August, w i t h  most o f i t o c c u r r i n g i n t h e f i r s t two M a t e r i a l examined:—  months.  lo", 25.IV.64; lo", 8.V.64; 1 o", 25.V.64;  lo", 8 . V I I I . 6 4 ; 1<*, 7.V.64; 1 pup. exuv., 7.V.64; 1 pup. exuv., 21.V.64; 3 l a r v . , 15.IV.64; I l a r v . , 7.V.64; 1 l a r v . , 21.V.64, M a r i o n L a k e ,  B.C.  Genus POLYPEDILIUM K i e f f e r P o l y p e d i l i u m K i e f f e r , 1913, B u l l . Soc. Nat. H i s t . Metz. 28: 15 P o l y p e d i l i u m Townes, 1945, Am.  M i d i . Nat. 34:36  P o l y p e d i l i u m Freeman, 1958, B u l l . B r . Mus. n a t . H i s t . E n t . 6(11):266-267 Three s p e c i e s o c c u r i n M a r i o n Lake.  Polypedilium  (Polypedilium)  nubeculosum  (Meigen)  Chironomus n u b e c u l o s u s Meigen, 1804, K l a s s . B e s c h r . europ. z w e i f l . I n s . , p. 18 T h i s s p e c i e s was r e a r e d .  The a d u l t s appear t o be  i d e n t i c a l t o t h o s e d e s c r i b e d by Townes (1945) and t h e y almost c e r t a i n l y belong to t h i s s p e c i e s .  The l a r v a and pupa have  122 not been i n c l u d e d i n the monographs of Johannsen (1937b) o r Roback (1957) and no p r e v i o u s d e s c r i p t i o n s of these are known to the  stages  author.  Male i m a g o : — antenna, l e g s and abdomen b l a c k i s h brown, thorax black. segments.  Antenna: A.R.  2.0-2.17, f l a g e l l u m w i t h  13  Head: p a l p p r o p o r t i o n s 5:19:18:21; c l y p e u s  with  33-35 h a i r s ; f r o n t a l t u b e r c l e s absent; t e m p o r a l h a i r s i n s i n g l e rows which n e a r l y meet at the mid  l i n e of head.  Thorax: pronotum p r o j e c t s beyond mesoscutum; d o r s o - c e n t r a l b r i s t l e s i n a d o u b l e i r r e g u l a r row; 12 i n a d o u b l e i r r e g u l a r row  supra-alar b r i s t l e s  a n t e r i o r l y and a s i n g l e  10-  row  p o s t e r i o r l y ; s c u t e l l u m w i t h 2 to 3 t r a n s v e r s e rows of bristles.  Wing: l e n g t h 2.7-2.9 mm. (3) ; R, R-^ and R^ g  with  +  m a c r o t r i c h i a ; wing membrane w i t h a few s c a t t e r e d m a c r o t r i c h i a ; R-L and R2+3 w e l l s e p a r a t e d beyond r-m.  Legs: L.R.  at t i p s ; c u b i t a l f o r k s l i g h t l y  1.55(1); f o r e t a r s u s w i t h a  sparse  b e a r d ; t i b i a l combs on each m i d d l e and h i n d l e g s e p a r a t e , one of them w i t h a l o n g s p u r and the o t h e r unarmed.  Hypo-  pygium: ( F i g . 16-A); a n a l p o i n t l o n g and narrow; s u p e r i o r appendage l o n g , s l i g h t l y curved b r i s t l e ; s t y l e l o n g and  and w i t h a l o n g  lateral  sac-like.  P u p a : — l e n g t h 6.4-7.2 mm.(6). a large preapical b r i s t l e .  C e p h a l i c t u b e r c l e : low,  R e s p i r a t o r y organ:  with  filamentous.  Abdomen: t e r g i t e I not shagreened; t e r g i t e I I - V I shagreened and w i t h s m a l l c i r c u l a r bare s p o t s w i t h i n the shagreen ( F i g .  123 16-B); t e r g i t e V I I and V I I I not shagreened, but  sternites  V I I and V I I I w i t h a p a t c h of f i n e s p i n u l e s near each a n t e r o l a t e r a l margin; l a t e r a l f i l a m e n t s on segments V - V I I I 3-3-4-4; s p u r on c a u d o - l a t e r a l margin of segment V I I I w i t h 1-5 s p i n e s and numerous s m a l l e r s p i n e s each w i t h 29-41 Larva:—  main  ( F i g . 16-C); a n a l  lobes  marginal f i l a m e n t s .  r e d , maximum l e n g t h 14 mm.  l e n g t h about 0.15  mm.;  Antenna: ( F i g . 16-D);  a n t e n n a l p r o p o r t i o n s 30:10:7:6:2;  s e n s o r i u m on b a s a l 1/4  of segment 1 and a n t e n n a l b l a d e  extends  t o t i p of segment 5.  Head: l e n g t h 0.46-0.53 mm.(3), e y e s p o t s  ( F i g . 16-E)  separated  and  ( F i g . 16-F)  w i t h 16 t e e t h , the median, second l a t e r a l s  penultimate  l a t e r a l t e e t h are l o n g e r than a d j a c e n t  mandible ( F i g . 16-G)  i n v e r t i c a l plane; l a b i a l p l a t e  w i t h a d a r k a p i c a l t o o t h , two  l a t e r a l s and a d a r k d o r s o - m e s a l t o o t h .  and  teeth; dark  Abdomen: a n a l p a p i l l a  c o n i c a l , l e n g t h e q u a l t o w i d t h at base and w i t h 7 o r 8 a p i c a l b r i s t l e s ; a n a l g i l l s n e a r l y as l o n g as p o s t e r i o r p r o l e g s , rounded a p i c a l l y and each w i t h a c o n s p i c u o u s c o n s t r i c t i o n near c e n t e r . Ecology:—  T h i s s p e c i e s i s abundant i n Marion L a k e .  Benthic  l a r v a e were c o l l e c t e d a t d e p t h s of 0.5-4.5 metres and i n 1964  a d u l t emergence l a s t e d from the second week of J u l y  u n t i l the second week of August. M a t e r i a l e x a m i n e d : — 2Co",  20.VI.63; lo", 25.VI1.64; 5  pup.  124 exuv., 20.VI.63; 1 pup., Marion Lake,  15.VII.64; 3 l a r v . , 29.IV.64,  B.C.  P o l y p e d i l i u m (Pentapedilium) Chironomus t r i t u s Walker, 1856,  t r i t u m (Walker)  I n s e c t a B r i t a n n i c a 3:162,  342 P o l y p e d i l i u m (Pentapedilium) Nat.  t r i t u m Townes, 1945,  Am.  Midi.  34:62-63  T h i s s p e c i e s was  not r e a r e d , but the l a r v a i s  almost c e r t a i n l y c o r r e c t l y a s s o c i a t e d .  The  a d u l t male agrees  w e l l w i t h those d e s c r i b e d by Townes (1945) except t h a t s t y l e s are b r o a d e r and more s a c - l i k e . b o t h key to P. t r i t u m i n Roback  The  l a r v a and pupa  (1957).  Male i m a g o : — a n t e n n a l f l a g e l l u m and  l e g s brown;  antennal  p e d i c e l b r o w n i s h orange; t h o r a x brownish orange and g r e e n i s h brown.  Antenna: A.R.  f l a g e l l u m w i t h 13 segments.  the  abdomen  1.69-1.94, mean 1.78(6), Head: p a l p p r o p o r t i o n s 5:13:13:  18; c l y p e u s w i t h 23-26 b r i s t l e s ( 4 ) ; f r o n t a l t u b e r c l e s absent; t e m p o r a l h a i r s i n s i n g l e rows which almost meet at the l i n e of head. s i n g l e row,  Thorax: d o r s o - c e n t r a l b r i s t l e s u s u a l l y i n a  o c c a s i o n a l l y the p o s t e r i o r b r i s t l e s are i n an  i r r e g u l a r d o u b l e row; row;  s u p r a - a l a r b r i s t l e s 5-6  s c u t e l l u m w i t h a s i n g l e t r a n s v e r s e row of  Wing: l e n g t h 1.9-2.2 mm.; R2+3 and  mid  wing membrane and  in a single bristles.  a l l v e i n s except  IA w i t h numerous m a c r o t r i c h i a ; R i and R2+3 s e p a r a t e d  125 a t t i p s ; c u b i t a l f o r k c o n s i d e r a b l y beyond r-m. 1.36-1.54(3); f o r e t a r s u s w i t h o u t  Legs:  L.R.  a b e a r d ; apex of f o r e  t i b i a w i t h a p o i n t e d s c a l e which t e r m i n a t e s  i n a conspicuous  s p u r ; t i b i a l combs on each m i d d l e and h i n d l e g s e p a r a t e , w i t h a l o n g s p u r and the o t h e r unarmed.  one  Hypopygium: ( F i g .  16-H); a n a l p o i n t l o n g and narrow; s u p e r i o r appendage horn shaped, w i t h one o r r a r e l y two and  lateral bristles; style  long  sac-like.  P u p a : — l e n g t h 3.9-4.9 mm.(8). a preapical bristle.  C e p h a l i c t u b e r c l e : low w i t h  R e s p i r a t o r y organ:  filamentous.  Abdomen: t e r g i t e I not shagreened; t e r g i t e s I I - V I w i t h shagreen on most of the d i s c ( F i g . 16-1), but s t r o n g e r near a n t e r i o r and p o s t e r i o r margins; t e r g i t e V I I w i t h a p a t c h  of  s p i n u l e s near each a n t e r o - l a t e r a l margin and t e r g i t e V I I I not shagreened; s p u r at c a u d o - l a t e r a l margin of segment V I I I each w i t h 2-4  main s p i n e s and 2-5  smaller spines ( F i g .  1 6 - J ) ; l a t e r a l f i l a m e n t s on segments V - V I I I 3-3-4-4; a n a l l o b e s each w i t h 21-26 Larva:—  marginal f i l a m e n t s .  r e d , maximum l e n g t h 7 mm.  l e n g t h about 0.11  mm.;  s e n s o r i u m on b a s a l 1/6  Antenna: ( F i g . 16-K);  a n t e n n a l p r o p o r t i o n s 20:7:6:5:2; of segment 1 and a n t e n n a l  extends about to the t i p of segment 5. 0.37(3); e y e s p o t s ( F i g . 16-L) p l a t e ( F i g . 16-M) and p e n u l t i m a t e  narrowly  Head:  blade  length  separated;  0.35-  labial  w i t h 16 t e e t h , the medians, second l a t e r a l t e e t h are l o n g e r than a d j a c e n t  laterals teeth;  126 mandible ( F i b . 16-N)  w i t h a d a r k a p i c a l t o o t h , two  l a t e r a l s and a d a r k d o r s o - m e s a l t o o t h .  dark  Abdomen: a n a l  p r p i l l a s l i g h t l y t a p e r e d , about as l o n g as w i d t h at base and w i t h 7 o r 8 a p i c a l b r i s t l e s ; a n a l g i l l s  ( F i g . 16-0)  long,  narrow and t a p e r i n g t o a p o i n t , l e n g t h e q u a l t o o r g r e a t e r than l e n g t h o f p o s t e r i o r p r o l e g s . Ecology:—  T h i s s p e c i e s i s abundant i n M a r i o n L a k e .  were c o l l e c t e d at depths of 0.5-3.5 metres and  in  Larvae 1964  a d u l t emergence o c c u r r e d from e a r l y August u n t i l e a r l y October. M a t e r i a l e x a m i n e d : — lei", 2 5 . V I I . 6 3 ; Id", 2 8 . V I I . 6 3 ; lo", 23. VI11.64; 3o"c; ?. VI11.64; 1 pup., V I I I . 6 4 ; 1 pup.,  13.IX.64; 3 pup.  19. VI11. 64; 1 pup.,  23.  exuv., 2.IX.64; 2  pup.  exuv., 13.IX.64; 3 l a r v . , 1 9 . V I I I . 6 4 ,  M a r i o n Lake,  P o l y p e d i l i u m (Tripodura) simulans  B.C.  Townes  Chironomus ( P o l y p e d i l i u m ) h a l t e r a l i s M i l l e r , 1941,  Univ.  Toronto S t u d . b i o l . S e r . 41:29, 31, 44, 47, 49, 50, 59, 61,  48,  62  P o l y p e d i l i u m (Tripodura) simulans  Townes, 1945,  Am.  Midi.  Nat. 34:43-44 T h i s s p e c i e s was  not r e a r e d but the l a r v a i s  almost c e r t a i n l y c o r r e c t l y a s s o c i a t e d . t o P. s i m u l a n s  The  a d u l t male keys  i n Townes (1945) but has a lower  antennal  127 ratio  (1.20-1.44 compared t o 1.8) and a lower l e g r a t i o  (1.33-1.38 compared t o 1.65) than t h e a d u l t s t h a t he d e s cribed.  S u b l e t t e (1960) measured two a d u l t s o f P.  simulans  and t h e i r a n t e n n a l r a t i o s were 1.02 and 1.88, i n d i c a t i n g that t h i s character i s very v a r i a b l e f o r the species.  The  immature s t a g e s o f t h i s s p e c i e s have a p p a r e n t l y not been described.  The l a r v a and pupa both key t o a c l o s e l y r e l a t e d  s p e c i e s , P. h a l t e r a l e (Coq.), i n Roback Male i m a g o : — brownish b l a c k .  (1957).  Antenna: A.R. 1.20-1.44, mean  1.28(4), f l a g e l l u m w i t h 13 segments.  Head: p a l p  proportions  4:14:13:21; c l y p e u s w i t h 12-17 b r i s t l e s ; t e m p o r a l h a i r s i n s i n g l e rows which n e a r l y meet a t t h e mid l i n e o f head. Thorax: d o r s o - c e n t r a l b r i s t l e s i n a s i n g l e row; s u p r a - a l a r b r i s t l e s about 5 i n a s i n g l e row; s c u t e l l u m w i t h a s i n g l e t r a n s v e r s e row o f b r i s t l e s .  Wing: l e n g t h 1.9-2.4 mm.;  R,  R^ and o u t e r h a l f o f R4 5 w i t h m a c r o t r i c h i a ; wing membrane +  w i t h o u t o r w i t h v e r y few m a c r o t r i c h i a ; R^ and R2+3 w i d e l y separated  a t t i p ; c u b i t a l f o r k beyond r-m. Legs: L.R. 1.33-  1.38(2); f o r e t a r s u s w i t h a s p a r s e b e a r d ; s c a l e a t apex o f fore t i b i a  w i t h a minute s p i n e o r no s p i n e a t a l l ;  tibial  combs on each m i d d l e and h i n d l e g s e p a r a t e , one w i t h a spur and t h e o t h e r unarmed; p u l v i l l i b i f i d .  Hypopygium: ( F i g .  16-P); a n a l p o i n t broad w i t h two d i s t i n c t l a t e r a l p r o j e c t i o n s at base and a c o n s t r i c t i o n about 2/3 o f t h e d i s t a n c e t o t h e tip,  apex e n l a r g e d  and p o i n t e d ; s u p e r i o r appendage about 3  times as l o n g as b r o a d , covered  w i t h m i c r o t r i c h i a and  128 a p i c a l l y w i t h s e v e r a l inward d i r e c t e d b r i s t l e s ;  inferior  appendage l o n g and narrow w i t h 12 o r 13 l o n g s p i n e s ; c o x i t e s h o r t and s t y l e l o n g and  narrow.  P u p a : — l e n g t h 4.2-4.9 mm.(5). with long p r e a p i c a l b r i s t l e .  Cephalic tubercles: short  R e s p i r a t o r y organ:  filamentous.  Abdomen: t e r g i t e I not shagreened; t e r g i t e s I I - V w i t h a shagreen p a t t e r n s i m i l a r to t h a t i n F i g u r e 16-Q;  t e r g i t e VI  w i t h an a n t e r i o r band of shagreen, but w i t h few s p i n u l e s on remainder of d i s c ; t e r g i t e s V I I and V I I I not shagreened; l a t e r a l f i l a m e n t s on segments V - V I I I 3-3-4-4; comb on caudol a t e r a l margin of segment V I I I w i t h 2-8  spines  ( F i g . 16-R);  a n a l l o b e s each w i t h 25-34 m a r g i n a l f i l a m e n t s . Larva:—  r e d , maximum l e n g t h 7 mm.  l e n g t h about 0.11  mm.;  s e n s o r i u m on b a s a l 1/3 1.25  Antenna: ( F i g . 16-S);  a n t e n n a l p r o p o r t i o n s 11:5:1:4:1; of segment 1 and a n t e n n a l b l a d e  times as l o n g as segments 2-5  0.30-0.34(3); e y e s p o t s ( F i g . 16-T) c a l p l a n e ; l a b i a l p l a t e ( F i g . 16-U)  combined. separate  about  Head: l e n g t h and  in a verti-  w i t h 16 t e e t h , the  medians and second l a t e r a l p r o j e c t beyond a d j a c e n t  teeth;  mandible w i t h a l a r g e d a r k a p i c a l t o o t h and 3 d a r k  lateral  teeth.  Abdomen: a n a l p a p i l l a about as l o n g as broad, w i t h  8 a p i c a l b r i s t l e s ; a n a l g i l l s rounded a p i c a l l y , c o n s t r i c t e d near c e n t e r and Ecology:—  about as l o n g as p o s t e r i o r p r o l e g s .  T h i s i s a common s p e c i e s i n Marion Lake.  Benthic  129 l a r v a e were c o l l e c t e d at depths of 0.5-3.5 metres and i n 1964 a d u l t emergence took p l a c e from mid J u l y u n t i l  mid  September. M a t e r i a l e x a m i n e d : — 4<*<t, ?. VI11.64; 1 pup., pup.,  14. VI11.64; 1  1 9 . V I I I . 6 4 ; 1 pup. exuv., 1 4 . V I I I . 6 4 ; 2 pup.  ? . V I I I . 6 4 ; 3 l a r v . , 1 9 . V I I I . 6 4 , Marion Lake,  exuv.,  B.C.  Genus SERGENTIA K i e f f e r S e r g e n t i a K i e f f e r , 1922, B u l l . Soc. e n t . F r . 1921:288 T a n y t a r s u s subg. T a n y t a r s u s Townes, 1945, Am.  Midi.  Nat.  34:71  S e r g e n t i a sp. A The male imago keys t o S_. a l b e s c e n s (Townes) i n Townes (1945) but the s h a r p l y bent s u p e r i o r appendage of the hypopygium more c l o s e l y resembles t h a t of S_. c o r a c i n u s (Zett.).  However, t h e male imago of S. c o r a c i n u s has a much  h i g h e r a n t e n n a l r a t i o and i s a l a r g e r i n s e c t than t h a t of S_. sp. A.  The pupa i s s i m i l a r t o t h o s e of S. f l a v i p e s  and S. obediens  (Johannsen)  (Meigen)  but i t i s l a r g e r than t h a t o f  S. f l a v i p e s and has fewer f i l a m e n t s on the a n a l l o b e s than the pupa of S. o b e d i e n s .  The  l a r v a i s s i m i l a r t o t h a t of S.  obediens but can be s e p a r a t e d on the b a s i s of the a n t e n n a l ratio,  the s h o r t e r median t e e t h on the l a b i a l p l a t e and  l o n g m e d i a l e x t e n s i o n o f the p a r a l a b i a l p l a t e s .  the  130 Male i m a g o : — t h o r a x and abdomen b l a c k i s h , l e g s brownish green.  Antenna: A.R.  w i t h 13 segments.  2.21-2.50, mean 2 . 3 6 ( 5 ) , f l a g e l l u m  Head: p a l p p r o p o r t i o n s 9:24:21:27; c l y p e u s  w i t h 24-30 b r i s t l e s ( 6 ) ; t e m p o r a l h a i r s e x t e n d i n g rows almost to mid  l i n e of head.  b r i s t l e s i n a s i n g l e row  Thorax: d o r s o - c e n t r a l  a n t e r i o r l y and an i r r e g u l a r double  row p o s t e r i o r l y ; s c u t e l l u m w i t h two tles.  Wing: l e n g t h 3.4-4.1 mm.,  c r o s s - v e i n r-m  in single  t r a n s v e r s e rows of  mean 3.5;  to apex, denser near apex.  bris-  m a c r o t r i c h i a from Legs: L.R.  1.17(6); f o r e t a r s u s w i t h m o d e r a t e l y heavy b e a r d ;  1.05-  tibial  combs on m i d d l e l e g f u s e d w i t h a s i n g l e s p i n e which i s l o n ger than 1/3  the d i a m e t e r of t i b i a at apex; h i n d t i b i a l combs  f u s e d w i t h two n e a r l y e q u a l s p i n e s .  Hypopygium: ( F i g . 17-A);  a n a l p o i n t l o n g , a p i c a l l y rounded and u s u a l l y s l i g h t l y e n l a r ged at t i p ; s u p e r i o r appendage s t r o n g l y c u r v e d , a l a t e r a l b r i s t l e ; c o x i t e elongate, extending  rarely with  about to t i p of  anal point. P u p a : — l e n g t h 5.7-7.7 mm.(11).  Cephalic tubercle: short,  t r u n c a t e d w i t h inward d i r e c t e d s p i n e - l i k e s t r u c t u r e s at apex (Fig.  17-B).  Abdomen: t e r g i t e I not shagreened; t e r g i t e I I  w i t h an a n t e r i o r t r a n s v e r s e band of s p i n u l e s , shagreen p a t t e r n on d i s c w i t h s m a l l c i r c u l a r f e n e s t r a t i o n s ; t e r g i t e s I I I and  IV w i t h shagreen p a t t e r n s s i m i l a r t o t h a t of t e r g i t e I I  but w i t h a t r a n s v e r s e band of s p i n u l e s a l o n g c a u d a l margin ( F i g . 1 7 - C ) ; t e r g i t e s V and VI shagreened but w i t h o u t ior  a poster-  t r a n s v e r s e band of s p i n u l e s ; t e r g i t e s V I I and V I I I  without  131 shagreen; l a t e r a l f i l a m e n t s on segments V - V I I I u s u a l l y 4-4; 17-D)  comb on c a u d o - l a t e r a l margin of segment V I I I ( F i g , w i t h 6-11  Larva:—  s p i n e s ; a n a l l o b e s each w i t h 25-36 f i l a m e n t s .  r e d , maximum l e n g t h 13 mm.  l e n g t h about 0.15  mm.;  s e n s o r i u m on b a s a l 2/5 as l o n g as segments 2-5 mean 0.56  Antenna: ( F i g . 17-E);  a n t e n n a l p r o p o r t i o n s 28:12:3:3:2; of segment 1 and a n t e n n a l b l a d e combined.  about  Head l e n g t h 0.53-0.59  mm.,  mm.(11); e y e s p o t s l a r g e , s e p a r a t e d , w i t h d o r s a l  eyespot s l i g h t l y a n t e r i o r ( F i g . 17-F); 17-G)  3-3-  labial plate (Fig.  w i t h 15 o r 16 t e e t h (the medians may  connected),  first  o r may  not  and t h i r d l a t e r a l s l o n g e r than  be  adjacent  t e e t h ; p a r a l a b i a l p l a t e s e n d i n g m e d i a l l y i n a narrow p o i n t which extends to j u n c t u r e of f i r s t and second  curved laterals  ( F i g . 17-G); mandible w i t h a d a r k a p i c a l t o o t h , f o u r dark l a t e r a l s and a l i g h t d o r s o - m e s a l t o o t h .  Abdomen: a n a l pap-  i l l a about as l o n g as b r o a d , w i t h 7 o r 8 a p i c a l  bristles;  a n a l g i l l s rounded a p i c a l l y , c o n s t r i c t e d near c e n t e r  and  n e a r l y as l o n g as p o s t e r i o r p r o l e g s . Ecology:—  T h i s i s an abundant s p e c i e s i n Marion Lake.  B e n t h i c l a r v a were c o l l e c t e d at depths of 3.0-6.0 metres. T h i s s p e c i e s has a one  year l i f e c y c l e and  i t has two s e p a r a t e p e r i o d s of emergence. f i r s t emergence p e r i o d o c c u r r e d  i n May  i n Marion Lake I n 1964  the  and e a r l y June w h i l e  the second took p l a c e from l a t e August u n t i l e a r l y O c t o b e r . There were no d e t e c t e d m o r p h o l o g i c a l  d i f f e r e n c e s between  132  i n d i v i d u a l s o f these two p o p u l a t i o n s but measurements o f t h e l a r v a e by season i n d i c a t e d t h a t the p o p u l a t i o n s were completely  separate.  M a t e r i a l examined:— 2°"cf 64;  Id", 4 . X . 6 4 ;  64;  2  pup.  16.V.63;  1  11.V.64;  1°", 15.V.64;  6 pup. exuv., ? . V . 6 4 ;  exuv., 2 6 . V I I I . 6 4 ;  1  pup.  2d o* ,  2 pup. exuv.,  j  26.VIII. 23.VIII.  exuv., 4 . X . 6 4 ; 4 l a r v . ,  l a r v . , 13.V.64; 9 l a r v . , 1 9 . V I I I . 6 4 ,  Marion Lake,  B.C.  Genus TRIBELOS Townes Tanytarsus  (subg. T r i b e l o s ) Townes, 1 9 4 5 , Am. M i d i . N a t . 34:66  Tribelos protextus Tanytarsus  (Townes)  ( T r i b e l o s ) p r o t e x t u s Townes, 1 9 4 5 , Am. M i d i . N a t . 34:69  T h i s s p e c i e s was r e a r e d and the a d u l t male i s v e r y s i m i l a r t o those d e s c r i b e d by Townes ( 1 9 4 5 ) .  T. p r o t e x t u s  i s v e r y s i m i l a r t o T. jucundus (Walker) and the o n l y c h a r a c t e r t h a t w i l l d i s t i n g u i s h them i s c o l o r .  The s e p a r a t i o n  of two s p e c i e s on the b a s i s o f c o l o r a l o n e i s q u e s t i o n a b l e but u n t i l f u r t h e r c l a r i f i c a t i o n the specimens from M a r i o n Lake w i l l be i n c l u d e d i n Townes' s p e c i e s .  The immature  s t a g e s o f T. p r o t e x t u s have not been d e s c r i b e d .  The l a r v a  133 and pupa from Marion Lake are both v e r y s i m i l a r to those  of  T. jucundus (=dimorphus) and key t o t h i s s p e c i e s i n Johannsen  (1937b) and Roback  (1957).  Male i m a g o : — antenna and abdomen b l a c k . 13 segments.  l e g s b l a c k i s h brown, t h o r a x  Antenna: A.R.  and  2.50-2.88(3), f l a g e l l u m w i t h  Head: p a l p p r o p o r t i o n s 7:27:23:31;  clypeus  w i t h 25-34 b r i s t l e s ; t e m p o r a l h a i r s i n i r r e g u l a r d o u b l e rows which extend as f a r m e d i a l l y as v e r t e x a n g l e s of eyes. Thorax: d o r s o - c e n t r a l b r i s t l e s i n a s i n g l e i r r e g u l a r s u p r a - a l a r b r i s t l e s 7-8  i n a s i n g l e row;  i r r e g u l a r t r a n s v e r s e rows of b r i s t l e s . 3.9  mm.  R, R^ and  scutellum with Wing: l e n g t h  the o u t e r h a l f of R^ g +  wing membrane w i t h o u t m a c r o t r i c h i a ; R^  row;  3.5-  with macrotrichia; and R2+3 w e l l s e p a r -  ated at t i p s ; c u b i t a l f o r k c o n s i d e r a b l y beyond r-m. L.R.  1.18-1.25; f o r e t a r s u s w i t h o u t  t i b i a w i t h two s e p a r a t e s p u r and  the o u t e r one  two  Legs:  a b e a r d ; apex of m i d d l e  combs, the i n n e r one w i t h a s h o r t unarmed; combs on h i n d t i b i a  fused  o r n e a r l y f u s e d , w i t h one s h o r t s p u r and sometimes w i t h a second minute s p i n e .  Hypopygium: ( F i g . 17-H); a n a l p o i n t  m o d e r a t e l y l o n g and rounded a p i c a l l y ; base of s u p e r i o r appendage e n l a r g e d ,  i n n e r margin r i g h t - a n g l e d and  outer  margin w i t h a rounded l o b e which b e a r s s e v e r a l b r i s t l e s ; s t y l e l o n g and rounded a l o n g the l a t e r a l margin. P u p a : — l e n g t h 7.3-9.5 mm.(3).  Cephalic tubercle c o n i c a l  w i t h a p r e a p i c a l b r i s t l e and one o r ,two c o a r s e  apical  134 spines.  R e s p i r a t o r y organ: f i l a m e n t o u s .  Abdomen: t e r g i t e  I w i t h o u t shagreen; t e r g i t e s I I - V w i t h shagreen p a t t e r n s s i m i l a r t o t h a t i l l u s t r a t e d i n F i g u r e 17-1; t e r g i t e VI w i t h a s t r o n g a n t e r i o r band o f s p i n u l e s , but shagreen on r e m a i n d e r o f d i s c much reduced; t e r g i t e s V I I and V I I I not shagreened; l a t e r a l f i l a m e n t s on segments V - V I I I 3-3-4-5; comb on c a u d o - l a t e r a l margin o f segment V I I I w i t h 4-10 spines  ( F i g . 1 7 - J ) ; a n a l l o b e s each w i t h 60-76 f i l a m e n t s .  Larva:—  r e d , maximum l e n g t h 14 mm.  l e n g t h 0.15 mm.;  Antenna: ( F i g . 17-K);  a n t e n n a l p r o p o r t i o n s 28:14:3.5:3.5:2; sen-  s o r i u m on b a s a l 2/5 o f segment 1 and a n t e n n a l b l a d e  very  l o n g , about t w i c e the l e n g t h o f segments 2-5 combined; l a u t e r b o r n organs l a r g e , as l o n g as o r l o n g e r than segment 3. Head: l e n g t h 0.47-0.53 mm.(3); e y e s p o t s ( F i g . 17-L) v e r y s m a l l and w i d e l y s e p a r a t e d ;  l a b i a l p l a t e ( F i g . 17-M) w i t h  16 t e e t h , the medians and second l a t e r a l s much s h o r t e r than adjacent  t e e t h ; mandible ( F i g . 17-N) w i t h a l o n g d a r k a p i -  c a l t o o t h , 3 dark l a t e r a l s and a l i g h t dorso-mesal t o o t h . Abdomen: a n a l p a p i l l a about t w i c e as l o n g as broad and w i t h 8 a p i c a l b r i s t l e s ; a n a l g i l l s rounded a p i c a l l y , c o n s t r i c t e d near c e n t e r s and about 2/3 as l o n g as p o s t e r i o r p r o l e g s . Ecology:—  T h i s s p e c i e s i s abundant i n Marion Lake.  Benthic  l a r v a e were c o l l e c t e d a t depths from 0.5-4.5 metres and i n 1964  a d u l t emergence l a s t e d from e a r l y June u n t i l the end  of J u l y .  135 M a t e r i a l e x a m i n e d : — 2c?cj 25.V.65; lo", 14.VI.65; 3  pup.  exuv., 10.VI.65; 1 l a r v . , 1.IV.64; 2 l a r ., 15.IV.64, Marion Lake,  B.C. T r i b e TANYTARSINI Genus ZAVRELIA K i e f f e r  Z a v r e l i a K i e f f e r , 1914,  Arch. Hydrobiol.  Z a v r e l i a Freeman, 1958,  B u l l . B r . Mus.  2:73  nat. H i s t . Ent. j 6 ( l l ) :  355 One  s p e c i e s o c c u r s i n Marion Lake. Z a v r e l i a sp. A  T h i s s p e c i e s was  not r e a r e d bu the l a r v a i s almost  certainly correctly associated.  The  M a r i o n Lake specimens do  not appear to b e l o n g to any o f the s p e c i e s d e s c r i b e d i n the literature.  The  genus i s d e s c r i b e d as l a c k i n g p u l v i l l i  but  the M a r i o n Lake specimens have p u l v i l l i which are d i s t i n c t at a m a g n i f i c a t i o n of 400.  O t h e r a d u l t male c h a r a c t e r s such as  the 10 segmented f l a g e l l u m of the antenna are t y p i c a l of genus. (1957).  The  the  l a r v a and pupa both key to Z a v r e l i a i n Roback  According to Brundin's  classification  t h i s s p e c i e s would be p l a c e d i n the genus  (Brundin,  1948)  Stempelline11a  B r u n d i n , a genus w i t h i n the Z a v r e l i a group. Male i m a g o : — antenna and t h o r a x brown; l e g s l i g h t brown; abdomen dark green, c a u d a l segments brownish.  Antenna:  1.19-1.34, mean 1.26(4), f l a g e l l u m w i t h 10 segments. p a l p p r o p o r t i o n s 3:7:8:12; c l y p e u s w i t h 11-13  hairs;  A.R.  Head:  136  f r o n t a l t u b e r c l e s c y l i n d r i c a l and about t w i c e as l o n g as wide; t e m p o r a l h a i r s i n s i n g l e rows which extend m e d i a l l y to p o i n t s mid way  between v e r t e x a n g l e s of eyes and  l i n e of head; v e r t e x a n g l e s of eyes s e p a r a t e d a n o t h e r by about 3/4  the d i a m e t e r of head.  from  the  mid  one  Thorax: pronotum  p r o j e c t s s l i g h t l y beyond mesoscutum; d o r s o - c e n t r a l b r i s t l e s 6-8  i n a s i n g l e row;  one  s u p r a - a l a r b r i s t l e and  w i t h about 6 b r i s t l e s i n a t r a n s v e r s e row. 1.15-1.33 mm.;  Wing: l e n g t h  apex of wing broad and rounded, a n a l l o b e of  wing a b s e n t ; o u t e r 1/4  of wing membrane w i t h m a c r o t r i c h i a  a l l main wing v e i n s except R2+3 macrotrichia.  scutellum  Legs: L.R.  anc  *  and  b a s a l h a l f of M with  1.38-1.56 mean 1.48(4); apex of  t i b i a w i t h an i n n e r rounded s c a l e and  an o u t e r s p u r of about  the same h e i g h t ; t i b i a l combs on each m i d d l e and h i n d l e g s e p a r a t e , each w i t h a s p u r about t w i c e as l o n g as the t e e t h of the comb; p u l v i l l i p r e s e n t claws.  and more t h a n h a l f as l o n g as  Hypopygium: ( F i g . 18-A); a n a l p o i n t broad, a p i c a l l y  p o i n t e d and d a r k i n c o l o r ; appendage l a a p p a r e n t l y  lacking;  appendage 2a about 10 times as l o n g as b r o a d , w i t h h a i r s on d i s t a l h a l f ; i n f e r i o r appendage w i t h a narrow s t a l k and enlarged spinous  apex; c o x i t e l a r g e and s t y l e s h o r t  an  and  narrow. P u p a : — l e n g t h 2.8-2.9 mm.(2).  Cephalic t u b e r c l e , longer  t h a n wide and w i t h an a p i c a l f i l a m e n t r a t h e r than a s p i n e or b r i s t l e .  R e s p i r a t o r y organ: ( F i g . 18-B); about 0.45  mm.  the  137 l o n g ; p o i n t e d a p i c a l l y and covered  with short spinules.  Abdomen: t e r g i t e I not shagreened; t e r g i t e I I w i t h a s m a l l p a t c h of shagreen near the c a u d a l row of s p i n e s ;  tergites  I I I - V I w i t h 4 p a t c h e s of shagreen ( F i g . 18-C); t e r g i t e V I I and V I I I w i t h o u t  shagreen; c a u d o - l a t e r a l margin of segment  V I I I w i t h a s i n g l e d a r k s p u r ( F i g . 18-D); l a t e r a l f i l a m e n t s on segments V - V I I I 3-4-4-3; a n a l l o b e s each w i t h 20-21  mar-  ginal filaments. Larva:—  maximum l e n g t h 3.5  mm.  Antenna: ( F i g . 18-E);  a n t e n n a l p r o p o r t i o n s 26:25:6:6:3; b a s a l segment 0.067-0.81 mm.(7);long; a n t e n n a l b l a d e about 1.3  times as l o n g as  ments 2 to 5 combined; l a u t e r b o r n organs l a r g e and on p e t i o l e s which are a t t a c h e d  mm.;  by about the d i a m e t e r of the lower  s p o t ; l a b i a l p l a t e ( F i g . 18-F) e l o n g a t e and  eye-  w i t h 13 t e e t h , m i d d l e t o o t h  l i g h t i n c o l o r ; mandible ( F i g . 18-G)  with a  l o n g d a r k a p i c a l t o o t h , 3 d a r k l a t e r a l s and a d a r k mesal t o o t h .  short  to the p r o x i m a l and d i s t a l ends  of segment 2 r e s p e c t i v e l y . Head: l e n g t h 0.23-0.27 eyespots separated  seg-  dorso-  Abdomen: a n a l p a p i l l a about as l o n g as b r o a d ,  w i t h about 8 l o n g a p i c a l b r i s t l e s and a l o n g backward d i r e c t e d b r i s t l e a t base; a n a l g i l l s about 0.08  mm.  long,  curved downward, rounded a p i c a l l y and o f t e n s l i g h t l y  tapered.  Ecology:—  In  1964  T h i s i s a common s p e c i e s i n M a r i o n Lake.  a d u l t emergence began i n e a r l y June o v e r the  areas and was October.  shallow  not completed o v e r the deeper areas u n t i l  mid  138 M a t e r i a l e x a m i n e d : — 2o"cr 20.VI.65; lo", 5 . V I I I . 6 5 ; IX.65; 2 pup.  i c , 18.  exuv., 7.VI.65; 1 l a r v . , 27.V.64; 1 l a r v . ,  10.VI.64; 6 l a r v . , 22.VII.64, Marion Lake,  B.C.  Genus STEMPELLINA Bause S t e m p e l l i n a Bause, 1914,  Arch. Hydrobiol.  S t e m p e l l i n a Freeman, 1958,  B u l l . B r . Mus.  2:120 nat. H i s t .  Ent.  6(11):352-353 One  s p e c i e s o c c u r s i n Marion Lake.  Stempellina bausei T a n y t a r s u s b a u s e i K i e f f e r , 1911,  (Kieffer)  B u l l . Soc. Nat. H i s t . Metz.  27:46 Stempellina bausei Brundin, T h i s s p e c i e s was  1948,  Ark. Z o o l . 41A(2):14-16  not r e a r e d , but the l a r v a i s  almost c e r t a i n l y c o r r e c t l y a s s o c i a t e d . to £L b a u s e i i n Edwards (1929) and key to t h i s s p e c i e s i n B r u n d i n The  The  a d u l t male keys  the l a r v a and pupa both  (1948) and Roback  l a r v a and pupa agree r e m a r k a b l y w e l l w i t h the  (1957). published  d e s c r i p t i o n s but the wing l e n g t h of the a d u l t i s l e s s than t h a t g i v e n f o r S. b a u s e i by Coe, to 1.75-2.0 mm.)  and  1950  (1.2-1.4 mm.  compared  the a n t e n n a l f l a g e l l u m of the male has 12  d i s t i n c t segments r a t h e r than 10 d i s t i n c t and 2 i n d i s t i n c t segments.  I f the Marion Lake s p e c i e s i s i n f a c t S.  bausei  139  and not a v e r y c l o s e l y r e l a t e d s p e c i e s than t h i s i s , so f a r as i s known, the f i r s t North American r e c o r d . (1937b) and B r u n d i n  Johannsen  (1948) both r e f e r t o £5. b a u s e i as a  European s p e c i e s . Male i m a g o : — antenna and  l e g s brown; t h o r a x g r e e n i s h brown;  abdominal segments I-IV brownish green, segments V - V I I I g r e e n i s h brown.  Antenna: A.R.  f l a g e l l u m w i t h 12 segments. 8.5; 1.5  c l y p e u s w i t h 13-15  0.66-0.80, mean 0 . 7 3 ( 3 ) , Head: p a l p p r o p o r t i o n s : 3:8:7:  b r i s t l e s ; f r o n t a l t u b e r c l e s about  times as l o n g as b r o a d ; t e m p o r a l h a i r s i n s i n g l e rows  which extend m e d i a l l y t o p o i n t s about 2/3 the v e r t e x a n g l e s of eyes t o the mid a n g l e s of eyes s e p a r a t e d w i d t h of head. a s i n g l e row;  from one  the d i s t a n c e from  l i n e of head; v e r t e x  a n o t h e r by about 2/3  the  Thorax: d o r s o - c e n t r a l b r i s t l e s minute and one  s u p r a - a l a r b r i s t l e and s c u t e l l u m w i t h  l a r g e b r i s t l e s near the mid near the a n t e r i o r m a r g i n .  in two  l i n e and a row of f i n e h a i r s Wing: l e n g t h 1.2-1.4 mm.;  apex  broad and rounded; a n a l lobe absent; wing v e i n s except Sc, R  2+3  a n d  t n e  ^ a s a l 3/4  of M w i t h m a c r o t r i c h i a ; wing mem-  brane w i t h o u t m a c r o t r i c h i a .  Legs: L.R.  1.0-1.13; f o r e  w i t h a s h o r t a p i c a l s p i n e ; t i b i a l combs on each m i d d l e h i n d l e g s e p a r a t e , one w i t h a s h o r t s p u r and the unarmed; p u l v i l l i p r e s e n t  tibia and  other  and about h a l f as l o n g as  claws.  Hypopygium: ( F i g . 18-H); a n a l p o i n t narrow, rounded a p i c a l l y and w i t h o u t o v a l markings; s u p e r i o r appendage not  enlarged  140 a t t i p ; appendage l a l a r g e and  t e r m i n a t i n g w i t h about 3  s h o r t s p i n e s ; i n f e r i o r appendage w i t h a narrow s t a l k and enlarged spinous  apex; appendage 2a about 8 times as  as broad and w i t h h a i r s on the d i s t a l  an  long  half.  P u p a : — l e n g t h 2.8-3.0 mm.(7); C e p h a l i c t u b e r c l e : about as l o n g as g r e a t e s t w i d t h and w i t h a l o n g a p i c a l b r i s t l e . R e s p i r a t o r y organ: ( F i g . 18-1); about 0.23  mm.  a p i c a l l y and covered  Abdomen: t e r g i t e s  I and  with short s p i n u l e s .  long, pointed  I I not shagreened; t e r g i t e s I I I - V w i t h p a i r e d , c a u d a l l y  e n l a r g e d p a t c h e s of s p i n u l e s ( F i g . 1 8 - J ) ; t e r g i t e s V I I  and  V I I I w i t h p a i r e d p a t c h e s of f a i n t , shagreen; comb on caudol a t e r a l margin of segment V I I I ( F i g . 18-K) s p u r and 2-3  with a terminal  l a t e r a l s p u r s ; l a t e r a l f i l a m e n t s on segments  V - V I I I 3-4-4-3; a n a l l o b e s each w i t h 15-20  marginal  fila-  ments . Larva:—  maximum l e n g t h 3.5  mm.  Antenna: ( F i g . 18-L);  a n t e n n a l p r o p o r t i o n s 33:5:6:4:3; b a s a l segment 0.09-0.10 mm.(6). l o n g ; a n t e n n a l blade about 1.5 ments 2-5  times as l o n g as  combined; l a u t e r b o r n organs l a r g e , on  p e t i o l e s which are a t t a c h e d  i n n e r margin.  Head: l e n g t h 0.26-0.31 mm.;  spot b i l o b e d and  head  nearly contiguous,  l a r g e r than v e n t r a l one;  tuber-  along i t s  b l a c k i s h i n c o l o r and w i t h 2 t u b e r c l e s near the margin; e y e s p o t s ( F i g . 18-M)  short  to the apex of segment 2;  c l e a t base of antenna w i t h a palmate p r o c e s s  seg-  capsule dorso-caudal d o r s a l eye-  l a b i a l plate (Fig.  141 18-N)  w i t h 13 >,teeth, the m i d d l e one rounded  and l i g h t i n  c o l o r ; mandible w i t h a d a r k a p i c a l t o o t h , 3 dark l a t e r a l s and a l i g h t d o r s o - m e s a l t o o t h ; a c c e s s o r y t o o t h extends p a s t tip  of m a n d i b l e ; p r e m a n d i b l e  ( F i g . 18-0)  trifid.  Abdomen:  a n a l p a p i l l a about as l o n g as b r o a d , a p i c a l l y w i t h 8 b r i s t l e s and w i t h 2 s m a l l e r l a t e r a l b r i s t l e s ; a n a l conical,  about 0.08  mm.  l o n g and 0.05  mm.  gills  wide at base.  E c o l o g y : — T h i s i s a common s p e c i e s i n M a r i o n L a k e . were c o l l e c t e d emerging  Larvae  a t depths of 0.5-3.0 metres and i n 1964  a d u l t s were c o l l e c t e d  from June 3 u n t i l J u l y  B r u n d i n , 1949 s u g g e s t s t h a t t h i s s p e c i e s may  8.  have more than  one g e n e r a t i o n p e r y e a r ; however, the s p e c i e s i n M a r i o n Lake almost c e r t a i n l y has a one y e a r l i f e M a t e r i a l examined:— exuv., 17.VI.64;  cycle.  lo", 17. V I . 64; 2 Co*, ?.VI.64; 5 pup.  1 pup. exuv., 20.VI.64;  64; 5 l a r v . , 27.V.64; 1 l a r v . , 10.VI.64,  1 pup. exuv., M a r i o n Lake,  Genus LUNDSTROEMIA K i e f f e r L u n d s t r o e m i a K i e f f e r , 1921, A n n l s . Soc. e n t . F r . 90:36 L u n d s t r o e m i a Freeman, 1961, A u s t . J . Z o o l . Two  s p e c i e s o c c u r i n M a r i o n Lake.  9(4):720  ?.VI. B.C.  s  142  L u n d s t r o e m i a sp. A T h i s s p e c i e s was tentatively associated.  not r e a r e d and  the l a r v a i s o n l y  The main r e a s o n s f o r a s s o c i a t i n g  t h i s l a r v a w i t h the pupa and a d u l t i s i t s l a r g e s i z e  and  the c o i n c i d i n g of i t s time of d i s a p p e a r a n c e from the  lake  and  the p e r i o d of a d u l t emergence.  I t i s p o s s i b l e , however,  t h a t the l a r v a d e s c r i b e d as T a n y t a r s i n i sp. A (page 155) i n f a c t the l a r v a of t h i s s p e c i e s .  The  is  male imago i s sim-  i l a r t o t h a t of L. hyperboreus (Brundin) which i s d e s c r i b e d by B r u n d i n  (1949) under the genus P a r a t a n y t a r s u s ,  i t has h i g h e r a n t e n n a l and  l e g r a t i o s and  d i f f e r e n t arrangement of b r i s t l e s .  The  however,  t e r g i t e IX has  a  l a r v a and pupa both  key t o M i c r o p s e c t r a i n Roback (1957) but the presence of t i b i a l s p u r s i n the a d u l t p l a c e s t h i s s p e c i e s i n the genus Lundstroemia. Male i m a g o : — b l a c k .  Antenna: A.R.  f l a g e l l u m w i t h 13 segments. 17; c l y p e u s w i t h 21-23  1.72-1.89, mean 1.79(5),  Head: p a l p p r o p o r t i o n s 7:19:16:  b r i s t l e s ; f r o n t a l t u b c l e s about as  l o n g as b r o a d ; t e m p o r a l h a i r s i n s i n g l e rows which extend m e d i a l l y t o p o i n t s even w i t h o r s l i g h t l y p a s t v e r t e x of e y e s .  Thorax: pronotum not e x t e n d i n g  t o l e v e l of meso-  scutum; d o r s o - c e n t r a l b r i s t l e s i n a s i n g l e row; b r i s t l e s 1-2; bristles.  angles  supra-alar  s c u t e l l u m w i t h a s i n g l e t r a n s v e r s e row  of  Wing: l e n g t h 2.85-3.05 mm.(3); wing membrane and  a l l v e i n s except Sc, R2+3 and b a s a l h a l f of M w i t h  143 macrotrichia.  Legs: L.R.  1.20-1.35, mean 1.25(3); apex of  t i b i a w i t h a l o n g s p u r and  a shorter tubercle-like  struc-  t u r e ; f o r e t a r s u s w i t h a s p a r s e b e a r d ; . t i b i a l combs on each middle and h i n d l e g u n i t e d , e x t e n d i n g around the c i r c u m f e r e n c e present  and about 1/3  about h a l f  way  and w i t h 2 s h o r t s p i n e s ;  as l o n g as c l a w s .  pulvilli  Hypopygium: ( F i g .  18-P); a n a l p o i n t s h o r t , broad and rounded a p i c a l l y ; s u p e r i o r appendage e n l a r g e d a p i c a l l y ; appendage l a s h o r t t u b u l a r and about 3 times as l o n g as broad; appendage 2a rounded a p i c a l l y , s l i g h t l y c o n s t r i c t e d at base and  about  t w i c e as l o n g as g r e a t e s t w i d t h ; h a i r s on p e d i c e l of appendage 2a w i d e r than those near the apex. P u p a : — l e n g t h 4.8-7.2 mm.(6).  C e p h a l i c t u b e r c l e : about  as l o n g as g r e a t e s t w i d t h and w i t h a l o n g t e r m i n a l b r i s t l e . R e s p i r a t o r y organ: ( F i g . 18-.Q) ; about 0.65 covered  with long h a i r s .  mm.  long  and  Abdomen: t e r g i t e I , V I I and  not shagreened; t e r g i t e s I I I - V ( F i g . 18-R)  VIII  each w i t h p a i r e d  patches of dark s p i n u l e s and p a i r e d p a t c h e s of f i n e  sha-  green; t e r g i t e s I I and VI w i t h f i n e shagreen o n l y ; comb at c a u d o - l a t e r a l margin of segment V I I I ( F i g . 18-S) 4-8  d a r k m a r g i n a l s p i n e s and  10-20  smaller spines;  with lateral  f i l a m e n t s on segments V - V I I I 3-4-4-4 o r 3-4-4-5; a n a l  lobes  each w i t h 54-67 m a r g i n a l f i l a m e n t s . L a r v a : — m a x i m u m l e n g t h 10 mm.  Antenna: ( F i g . 18-T);  n a l p r o p o r t i o n s 110:38:5:5:3, b a s a l segment 0.27-0.29  antenmm.  144  (2)  l o n g ; t u b e r c l e a t base o f antenna w i t h a s h o r t s p u r ;  a n t e n n a l b l a d e about 1 / 4 as l o n g as segment 2 ; l a u t e r b o r n organs s m a l l , on p e t i o l e s about 4 times as l o n g as segments 3-5  combined.  18-U)  separate;  Head: l e n g t h 0 . 4 1 - 0 . 4 7 mm.; e y e s p o t s ( F i g . l a b i a l p l a t e ( F i g . 18-V) w i t h 11 t e e t h ,  middle tooth t r i f i d ;  mandible  ( F i g . 18-W) w i t h a d a r k  api-  c a l t o o t h , 3 dark l a t e r a l s and a d a r k dorso-mesal t o o t h ; premandible b i f i d .  Abdomen: a n a l p a p i l l a about 1 . 2 t i m e s as  l o n g as b r o a d , apex b r o w n i s h b l a c k and w i t h 8 c o a r s e b r i s t l e s ; a n a l g i l l s about 0 . 1 8 mm. l o n g and rounded  apically.  E c o l o g y : — T h i s i s a common s p e c i e s i n M a r i o n Lake.  Larvae  o c c u r r e d a t a l l depths and i n 1 9 6 4 a d u l t s emerged i n A p r i l and May o v e r t h e s h a l l o w p a r t s o f t h e l a k e and i n September and O c t o b e r o v e r the deeper w a t e r .  The a d u l t s t h a t emerged  i n t h e f a l l were s l i g h t l y l a r g e r , but i n o t h e r  respects  appear i d e n t i c a l t o t h o s e t h a t emerged i n t h e s p r i n g . M a t e r i a l examined:-64;  2  2dd,  10.IV.64;  2o*o", 1 6 . I V . 6 4 ;  pup. exuv., 2 . V . 6 4 ; 1 pup. exuv., 6 . V . 6 4 ;  8.V.64;  2  29.IV.64,  pup. exuv., 1 9 . I X . 6 4 ;  1  1  Id", 2.V.  pup.  exuv.,  larv., 12.11.64; 1 larv.,  M a r i o n Lake. B.C.  L u n d s t r o e m i a sp. B T h i s s p e c i e s was n o t r e a r e d and o n l y t h e pupa i s known.  I t i s p o s s i b l e t h a t t h e l a r v a d e s c r i b e d as T a n y t a r s i n i  145 sp. A i s the l a r v a of t h i s s p e c i e s . Paratanytarsus and had  and  The  pupa keys t o  the t i b i a l combs on a ? pupa were u n i t e d  two s h o r t s p u r s , p l a c i n g the specimen i n the genus  Lundstroemia ( i n c l u d e s P a r a t a n y t a r s u s ) . P u p a : — l e n g t h 3.6-4.6 mm.(3). a long a p i c a l b r i s t l e . as i n F i g u r e 20-K,  C e p h a l i c t u b e r c l e : low w i t h  Abdomen: t e r g i t e s I I I - V shagreened  remaining  t e r g i t e s not shagreened; comb  a t c a u d o - l a t e r a l margin of segment V I I I w i t h 6-11  marginal  s p i n e s and no o t h e r s p i n e s ; l a t e r a l f i l a m e n t s on segments V - V I I I 4-4-4-5; g e n i t a l s a c s each p a r t l y covered  with a  w a r t - l i k e s t r u c t u r e ; a n a l l o b e s each w i t h 37-40 m a r g i n a l filaments. Ecology:—  This i s a r a r e s p e c i e s i n Marion Lake.  pupae c o l l e c t e d were t a k e n d u r i n g June, M a t e r i a l e x a m i n e d : — 1 pup., Marion L a k e ,  The  only  1964.  7.VI.64; 2 pup.  exuv., ?.VI.64;  B.C.  Genus TANYTARSUS van d e r Wulp T a n y t a r s u s van d e r Wulp, 1874, T a n y t a r s u s Freeman, 1958, 11(6):331  T i j d s c h r . E n t . 17:134  B u l l . B r . Mus.  nat. H i s t .  Ent.  146 Tanytarsus (Tanytarsus) T h i s s p e c i e s was  sp. A  not r e a r e d but the l a r v a i s  l i k e l y correctly associated.  The male imago i s s i m i l a r to  but s m a l l e r t h a n the European s p e c i e s T. Edwards.  holochlorus  A l s o the i n f e r i o r appendage i s b r o a d e r and  dage 2a i s w i t h o u t broad f i l a m e n t s .  appen-  The male imago i s a l s o  s i m i l a r t o those of T. d e n d y i S u b l e t t e and T. xanthus Subl e t t e but i s l a r g e r than the a d u l t of e i t h e r s p e c i e s , has l o n g e r appendage l a than t h a t of T. d e n d y i a n a l p o i n t than t h a t of T. x a n t h u s . key t o the group C a l o p s e c t r a ,  The  a  and a d i f f e r e n t  l a r v a and pupa both  (=subg. T a n y t a r s u s ) i n Roback  (1957). Male i m a g o : — antenna brown; t h o r a x g r e e n i s h brown; abdomen green; legs brownish green.  Antenna: A.R.  1.50-1.56(2),  f l a g e l l u m w i t h 13 segments.  Head: p a l p p r o p o r t i o n s 4:11:13:  22; c l y p e u s w i t h 15-17(3) b r i s t l e s ; f r o n t a l t u b e r c l e s c y l i n d r i c a l , about t w i c e as l o n g as broad; t e m p o r a l h a i r s i n s i n g l e rows which n e a r l y meet at the mid Thorax: d o r s o - c e n t r a l b r i s t l e s 7-9  l i n e of head.  i n a s i n g l e row;  a l a r b r i s t l e s absent; s c u t e l l u m w i t h a s i n g l e row of b r i s t l e s . brane and Legs: L.R.  supra-  transverse  Wing: l e n g t h 2.4-2.55 mm.(3); wing mem-  a l l wing v e i n s except Sc and R2+3 w i t h m a c r o t r i c h i a . 2.0-2.24; f o r e t i b i a w i t h one  l o n g and one  minute  s p u r ; f o r e t a r s u s w i t h a s p a r s e b e a r d ; t i b i a l combs on each m i d d l e and h i n d l e g w i d e l y s e p a r a t e d ,  each w i t h one  spine  147 about 3 times as l o n g as the t e e t h of the comb; p u l v i l l i p r e s e n t but minute. w i t h 5-7  Hypopygium: ( F i g . 19-A); a n a l p o i n t  o v a l , markings i n a row which extends about h a l f  t o the apex; s u p e r i o r appendage w i t h about 7 c o a r s e  way  spines  and appendage l a s m a l l and f i n g e r - l i k e ; i n f e r i o r appendage v e r y l a r g e and appendage 2a e l o n g a t e w i t h most of i t s h a i r s concentrated  a l o n g the m e d i a l margin; s t y l e l o n g and  nar-  rower t h a n apex of i n f e r i o r appendage. P u p a : — l e n g t h 4.9-5.7 mm.(2).  Cephalic tubercle: long,  t r u n c a t e d a p i c a l l y and w i t h a l o n g a p i c a l b r i s t l e . p i r a t o r y organ: ( F i g . 19-B); about 0.28 few s c a t t e r e d h a i r s near apex.  mm.  Res-  l o n g and w i t h a  Abdomen: t e r g i t e I I w i t h  f i n e shagreen on d i s c ; t e r g i t e s I I I - V I w i t h p a i r e d  elongate  p a t c h e s of d a r k s p i n u l e s ( F i g . 19-C); t e r g i t e s V I I and V I I I w i t h o u t shagreen; comb a t c a u d o - l a t e r a l margin of segment V I I I ( F i g . 19-D)  w i t h 6-11  m a r g i n a l s p i n e s and  numerous  s m a l l e r s p i n e s ; l a t e r a l margins of segments V and VI each w i t h 2 o r 3 b r i s t l e s ; segments V I I and V I I I w i t h 4 o r 5 p a i r s of l a t e r a l f i l a m e n t s r e s p e c t i v e l y ; a n a l l o b e s each w i t h 33-41 Larva:—  marginal filaments.  maximum l e n g t h 8 mm.  Antenna: ( F i g . 19-E);  anten-  n a l p r o p o r t i o n s 72:25:64:2, b a s a l segment 0.194-0.208  mm.  (3) l o n g ; a n t e n n a l b l a d e about h a l f as l o n g as segment 2; l a u t e r b o r n organs s m a l l , on p e t i o l e s about 3.3 as segments 3-5  combined.  times as  Head: l e n g t h 0.34-0.37 mm.;  long eye  148 spots separated  by about t w i c e the d i a m e t e r of lower  s p o t ; l a b i a l p l a t e ( F i g . 19-F) one weakly t r i f i d  and  eye-  w i t h 11 t e e t h , the median  l i g h t i n c o l o r ; mandible w i t h a d a r k  a p i c a l t o o t h , 3 dark l a t e r a l s and  a large light  dorso-  mesal t o o t h ; p r e m a n d i b l e t r i f i d .  Abdomen: a n a l p a p i l l a  about as l o n g as broad and w i t h 8 a p i c a l b r i s t l e s ; gills  ( F i g . 19-G)  0.11-0.15 mm.  anal  l o n g , d o r s a l p a i r much  b r o a d e r than v e n t r a l ones. Ecology:—  T h i s i s a common s p e c i e s i n M a r i o n Lake.  Ben-  t h i c l a r v a e were c o l l e c t e d at depths of 0.5-3.0 metres in  1964  a d u l t emergence o c c u r r e d  i n October.  M a t e r i a l examined:— Id", 22.X.64; 2rfcj ?.X.64; 2 pup. 22.X.64; 3 l a r v . , 8.VII.64, Marion Lake.  Tanytarsus (Tanytarsus) T h i s s p e c i e s was been p r e v i o u s l y d e s c r i b e d .  sp.  exuv.,  B.C.  B  r e a r e d and has a p p a r e n t l y The  and  not  a d u l t male resembles t h a t  of T. xanthus S u b l e t t e but the l a r v a and pupa are more simi l a r t o t h o s e o f T. g u e r l a  (Roback).  Male i m a g o : — antenna, l e g s and  t h o r a x brown; abdomen  s c u t e l l u m and h a l t e r e s d a r k g r e e n . 1.33,  Antenna: A.R.  mean 1.31(3), f l a g e l l u m w i t h 13 segments.  p a l p p r o p o r t i o n s 4:10:11:15; c l y p e u s w i t h 13-17 f r o n t a l t u b e r c l e tapered  and rounded a p i c a l l y ;  1.28Head: bristles;  temporal  149 h a i r s i n s i n g l e rows which extend m e d i a l l y t o p o i n t s about 3/4 o f the way from the v e r t e x a n g l e s o f eyes t o the mid l i n e o f head.  Thorax: pronotum does not e x t e n d t o a p o i n t  l e v e l w i t h t h e mesoscutum; d o r s o - c e n t r a l b r i s t l e s 6-8 i n a s i n g l e row; s u p r a - a l a r b r i s t l e s absent and s c u t e l l u m w i t h a s i n g l e t r a n s v e r s e row o f f i n e b r i s t l e s . 1.90 mm.;  Wing: l e n g t h 1.75-  wing membrane and a l l v e i n s except  macrotrichia.  R 2 + 3  with  Legs: L.R. 2.0-2.38, mean 2.14(3); apex o f  f o r e t i b i a w i t h one s h o r t and one l o n g s p u r ; t i b i a l combs on each m i d d l e and h i n d l e g w i d e l y s e p a r a t e d and each w i t h a s p u r about 3 times as l o n g as the t e e t h o f comb; p u l v i l l i minute.  Hypopygium: ( F i g . 19-H); a n a l p o i n t broad w i t h 4-6  o v a l markings i n a row e x t e n d i n g t o near apex o f a n a l p o i n t ; apex o f s u p e r i o r appendage horn shaped w i t h t h e narrower p a r t d i r e c t e d toward t h e median l i n e ; appendage l a l o n g and t u b u l a r ; appendage 2a about t w i c e as l o n g as b r o a d ; s t y l e broad and p o i n t e d  apically.  P u p a : — l e n g t h 3.3-3.9 mm.(8). a long a p i c a l b r i s t l e .  C e p h a l i c t u b e r c l e ; low w i t h  R e s p i r a t o r y organ: ( F i g . 19-1);  rounded a p i c a l l y , w i t h o u t s p i n u l e s and about 0.08 mm.  long.  Abdomen: t e r g i t e s I I I and IV w i t h p a i r e d p a t c h e s o f l o n g dark s p i n e s  ( F i g . 1 9 - J ) ; t e r g i t e V and VI w i t h p a i r e d p a t c h e s  of d a r k s p i n u l e s ; comb on c a u d o - l a t e r a l margin o f segment V I I I ( F i g . 19-K) w i t h 4-7 l i g h t m a r g i n a l s p i n e s and 4-7 l i g h t s p i n e s a n t e r i o r t o t h e margin; segments V-VII w i t h 2 o r 3 p a i r s o f b r i s t l e s o r b r i s t l e - l i k e f i l a m e n t s ; segment  150 VIII  w i t h 4 o r 5 l a t e r a l f i l a m e n t s ; a n a l l o b e s each w i t h  43-49 m a r g i n a l f i l a m e n t s . L a r v a : — maximum l e n g t h 6 mm. nal  Antenna: ( F i g . 19-L);  anten-  p r o p o r t i o n s 88:37:7:3:1.5, b a s a l segment 0.24-0.28  (5) l o n g ; a n t e n n a l t u b e r c l e w i t h o u t a s p i n e and  mm.  antennal  b l a d e about h a l f as l o n g as segment 2; l a u t e r b o r n o r g a n s s m a l l , on p e t i o l e s about 3 times as l o n g as segments combined.  Head: l e n g t h 0.31-0.35 mm.;  widely separated;  l a b i a l p l a t e ( F i g . 19-N)  the m i d d l e one weakly t r i f i d (Fig.  19-0)  eyespots  and  2-5  (Fig.  19-M)  w i t h 11 t e e t h ,  l i g h t e r c o l o r e d ; mandible  w i t h a dark a p i c a l t o o t h , 3 d a r k l a t e r a l s and  l i g h t dorso-mesal teeth;,premandible  trifid.  2  Abdomen: a n a l  p a p i l l a about as l o n g as b r o a d ; a n a l g i l l s 0.12-0.15 l o n g , d o r s a l p a i r a p i c a l l y p o i n t e d and much b r o a d e r  mm.  than  v e n t r a l ones. Ecology:—  T h i s i s an abundant s p e c i e s i n M a r i o n Lake.  L a r v a e were c o l l e c t e d at depths o f 0.5-4.0 metres and 1964  in  a d u l t emergence began i n l a t e June, reached a peak r a t e  i n J u l y and c o n t i n u e d  u n t i l mid  M a t e r i a l examined:-- lo*, 65; 6 pup.  October.  2 7 . V I . 6 4 ; lo",  exuv., 2 7 . V I . 6 4 ; 2 pup.  5 . V I I . 6 4 ; Id",  20.VI.  exuv., 8 . V I I . 6 4 ; 1 l a r v . ,  2 9 . I V . 6 4 ; 4 l a r v . , 1 3 . V I . 6 4 , M a r i o n Lake,  B.C.  151 Tanytarsus (Tanytarsus) T h i s s p e c i e s was  reared.  sp. C  The male imago i s sim-  i l a r to t h a t of T. c u r t i c o r n u s K i e f f e r but has a narrower anal p o i n t , a higher antennal r a t i o and a lower l e g r a t i o  (1.63  (1.15  compared t o  compared t o 2.0).  The  0.8)  larva  keys t o the group L a u t e r b o r n i a and the pupa t o the group Calopsectra  (= subg. T a n y t a r s u s ) i n Roback  Male i m a g o : — antenna, l e g s and s c u t e l l u m dark green. (3),  t h o r a x brown; abdomen and  Antenna: A.R.  f l a g e l l u m w i t h 13 segments.  4:11:13:16; c l y p e u s w i t h 13-15  (1957).  1.09-1.26, mean  Head: p a l p  1.15  proportions  b r i s t l e s ; f r o n t a l tubercles  a b s e n t ; t e m p o r a l h a i r s i n s i n g l e rows which extend m e d i a l l y about 3/4 the mid  of the way  l i n e of head.  i n a s i n g l e row;  from the v e r t e x a n g l e s of the eyes to Thorax: d o r s o - c e n t r a l b r i s t l e s  no s u p r a - a l a r b r i s t l e s and s c u t e l l u m w i t h  a s i n g l e t r a n s v e r s e row of f i n e b r i s t l e s . 2.15-2.20 mm.;  7-9  apex of wing membrane and  Wing: l e n g t h at l e a s t the d i s -  t a l h a l f of most of the wing v e i n s w i t h m a c r o t r i c h i a . Legs: L.R.  1.62,.-1.64(2) ; f o r e t i b i a w i t h two  apical  spurs,  each about h a l f as l o n g as w i d t h of t i b i a at apex; t i b i a l combs on each m i d d l e and h i n d l e g w i d e l y s e p a r a t e d ,  each  w i t h a s p u r about t w i c e as l o n g as the t e e t h of comb; pulvilli  about 1/3  as l o n g as c l a w s .  Hypopygium: ( F i g .  20-A); a n a l p o i n t rounded a p i c a l l y and w i t h a row of o v a l markings a t base; s u p e r i o r appendage e l o n g a t e  5-7  and  152 appendage l a l a r g e and  lobe shaped; i n f e r i o r  l a r g e but not c o n s p i c u o u s l y  enlarged  a p p a r e n t l y absent; s t y l e l o n g and P u p a : — l e n g t h 3.3-4.4 mm.(10). with a long a p i c a l b r i s t l e . about 0.7 ules.  mm.  appendage  a t apex; appendage 2a  narrow. C e p h a l i c t u b e r c l e : low  R e s p i r a t o r y organ: ( F i g . 20-B);  l o n g , d i s t a l h a l f covered  w i t h narrow s p i n -  Abdomen: t e r g i t e s I I - V I w i t h p a i r e d p a t c h e s of d a r k  s p i n u l e s ( F i g . 20-C); t e r g i t e s I , V I I and V I I I  without  shagreen; c a u d o - l a t e r a l margin of segment V I I I ( F i g . w i t h a d a r k comb composed of 3-6  20-D)  l a r g e s p i n e s and s e v e r a l  s m a l l e r ones; l a t e r a l margins of segments V and VI each w i t h an a n t e r i o r b r i s t l e and 2 p o s t e r i o r f i l a m e n t s ; segments VII and V I I I w i t h 4 and  5 p a i r s of l a t e r a l f i l a m e n t s  t i v e l y ; a n a l l o b e s each w i t h 24-31 Larva:—  maximum l e n g t h 6 mm.  respec-  marginal f i l a m e n t s .  Antenna: ( F i g . 20-E);  anten-  n a l p r o p o r t i o n s 60:14:5:3:1.5, b a s a l segment 0.165-0.183 mm.(3) l o n g ; a n t e n n a l t u b e r c l e w i t h a l o n g curved s p u r which extends n e a r l y to the mid  l i n e of head; a n t e n n a l  blade  n e a r l y as l o n g as segment 2; l a u t e r b o r n organs s m a l l on p e t i o l e s about 4 times as l o n g as segments 2-5 Head: l e n g t h 0.25-0.30 mm.; separated;  l a b i a l p l a t e ( F i g . 20-G)  d l e one weakly t r i f i d 20-H)  e y e s p o t s ( F i g . 20-F)  and  lighter  combined. widely  w i t h 11 t e e t h , the midc o l o r e d ; mandible ( F i g .  w i t h a dark a p i c a l t o o t h ; 3 dark l a t e r a l s  dorso-mesal t o o t h , premandible t r i f i d .  and a  Abdomen: a n a l  light  153 p a p i l l a about as l o n g as broad; a n a l g i l l s 0.13 mm.  ( F i g . 20-1) about  l o n g , rounded a p i c a l l y and a l l o f much the same  shape and s i z e . E c o l o g y : — T h i s i s an abundant s p e c i e s i n M a r i o n Lake. B e n t h i c l a r v a e were t a k e n most f r e q u e n t l y a t depths of l e s s than 3.0 m e t r e s , but t h e y o c c u r r e d a t a l l d e p t h s .  I n 1964  a d u l t emergence began i n e a r l y May o v e r the s h a l l o w a r e a s and was not completed o v e r t h e deeper w a t e r u n t i l t h e end of August. M a t e r i a l e x a m i n e d : — 2.dd 6.V.64; Id", ?.V.64; Id", l . v . 6 5 ; }  1 pup. exuv., 1.V.64; 5 pup. exuv., 6.V.64; 3 pup. exuv., 18.V.64; 1 l a r v . , 1.IV.64; 2 l a r v . , 13.V.64, M a r i o n L a k e , B.C.  T a n y t a r s u s ( T a n y t a r s u s ) e x c a v a t u s Edwards T a n y t a r s u s e x c a v a t u s Edwards, 1929, T r a n s , e n t . Soc. Lond. 77:416 T h i s s p e c i e s was not r e a r e d and o n l y the male imago i s known.  The M a r i o n Lake specimens are s i m i l a r to  those d e s c r i b e d by Edwards  (1929) but a r e l i g h t e r c o l o r e d ,  have s h o r t e r wings (1.95-2.10 mm.  compared t o 2.5 mm.)  a h i g h e r l e g r a t i o (2.31-2.65 compared t o 2.1-2.2).  and Those  d i f f e r e n c e s were not c o n s i d e r e d i m p o r t a n t enough to w a r r a n t specific  distinction.  154 Male i m a g o : — a n t e n n a brown; t h o r a x and abdomen l i g h t green.  Antenna: A.R.  ( 4 ) , f l a g e l l u m w i t h 13 segments. 4:11:12:20; c l y p e u s w i t h 15-18  l e g s brownish green;  1.10-1.26, mean  Head: p a l p  1.18  proportions  b r i s t l e s ; frontal tubercles  absent; t e m p o r a l h a i r s i n s i n g l e rows which n e a r l y meet at the mid  l i n e of head.  i n a s i n g l e row;  Thorax: d o r s o - c e n t r a l b r i s t l e s  one o r two s u p r a - a l a r b r i s t l e s and  lum w i t h a s i n g l e t r a n s v e r s e row of b r i s t l e s . 1.95-2.10 mm.;  8-10  scutel-  Wing: l e n g t h  m a c r o t r i c h i a p r e s e n t on a l m o s t , a l l wing mem-  brane and membrane v e i n s , d e n s e s t near apex.  Legs:  L.R.  2.31-2.65; mean 2.44(4); apex of f o r e t i b i a w i t h a rounded s c a l e and a l o n g s p u r ; combs on each m i d d l e and h i n d l e g widely separated  each w i t h a s p u r about 3 times as l o n g as  the t e e t h of the comb; p u l v i l l i about 1/3  as l o n g as  Hypopygium: ( F i g . 2 0 - J ) ; a n a l p o i n t rounded a p i c a l l y  claws. and  w i t h o u t o v a l markings; s u p e r i o r appendage b i l o b e d ; appendage l a e n l a r g e d  a p i c a l l y ; appendage 2a b i l o b e d and  without  hairs. E c o l o g y : — T h i s i s a r a r e s p e c i e s i n M a r i o n Lake. emergence o c c u r r e d  i n June i n 1964  and  Adult  1965.  M a t e r i a l e x a m i n e d : — 1°*, 20.VI.64; 3°*°", 20.VI.65, Marion Lake,  B.C.  155 T a n y t a r s i n i sp. A T h i s s p e c i e s was known.  The  not r e a r e d and o n l y the l a r v a i s  l a r v a keys t o the group A t a n y t a r s u s  i n Roback  (1957), but the o n l y pupa found i n Marion Lake t h a t  will  key to t h i s group i s t h a t of T a n y t a r s u s sp. A, a r e a r e d species.  I t i s p o s s i b l e t h a t t h i s i s the l a r v a of  T.  e x c a v a t u s (page 153) o r t h a t of L u n d s t r o e m i a sp. A o r sp. B (pages 141, Larva:—  143).  maximum l e n g t h 7.0  mm.  Antenna: ( F i g . 20-M);  a n t e n n a l p r o p o r t i o n s 34:5:13:5:2; b a s a l segment 0.096-0.102 mm.(6) l o n g ; a n t e n n a l 4/5  tubercle without  about  as l o n g as b a s a l segment of antenna; l a u t e r b o r n organs  v e r y l a r g e , on s h o r t p e t i o l e s a t t a c h e d ment 2.  to the apex of  seg-  Head: l e n g t h 0.27-0.31 mm.(5); e y e s p o t s ( F i g . 20-  N) s e p a r a t e ;  l a b i a l p l a t e w i t h 11 t e e t h , the middle one  t r i f i d , u s u a l l y t r u n c a t e d and (Fig.  a spur and  20-P)  is  l i g h t e r i n c o l o r ; mandible  w i t h a d a r k a p i c a l t o o t h , 3 d a r k l a t e r a l s and  a  s h o r t l i g h t c o l o r e d d o r s o - m e s a l t o o t h ; premandible w i t h 4 pointed teeth.  Abdomen: a n a l p a p i l l a about as l o n g as  broad, w i t h 8 coarse a p i c a l b r i s t l e s ; anal g i l l s  (Fig.  about 0.17  sharply  mm.  l o n g , rounded a p i c a l l y and curved  20-Q)  downward. Ecology:—  L a r v a e of t h i s s p e c i e s are common at a l l depths  i n Marion Lake and the a d u l t s a p p a r e n t l y emerge d u r i n g s p r i n g and e a r l y summer.  the  156  M a t e r i a l examined:— 4 l a r v . , l.IV.64; 1 l a r v . , 1 l a r v . , 29.IV.64, M a r i o n Lake, B.C.  15.IV.64;  Figure 1 Taxonomic terminology of the a d u l t Chironomidae Chironominae - D o r s a l view of head  (one antenna  removed) Chironominae - F o r e - l e g showing t a r s a l beard Tanypodinae - L a t e r a l view of thorax Chironominae - Wing Chironomini - Hypopygium  157  158a  Figure 2 Taxonomic t e r m i n o l o g y the immature Chironomidae A  C h i r o n o m i n i - v e n t r a l view o f l a r v a l head  B  Tanypodinae - v e n t r a l view o f l a r v a l head  C  C h i r o n o m i n i - l a t e r a l view o f l a r v a l p o s t abdomen  D  C h i r o n o m i n i - the two c a u d a l segments o f pupa  E  C h i r o n o m i n i - a n t e r i o r segments of p u p a l  exuviae  158  159a  Figure 3 Key c h a r a c t e r s o f t h e Tanypodinae and t h e M a c r o p e l o p i i n i (length of s c a l e l i n e i n d i c a t e d  i n parenthesis).  Tanypus Sp. A A - C a u d a l end o f pupa (1.0 mm.) P s i l o t a n y p u s b e l l u s (Loew) B - Hypopygium o f male imago (0.25 mm.) C - R e s p i r a t o r y o r g a n o f pupa (0.25 mm.) D - C a u d a l end o f pupa (1.0 mm.) E - L a t e r a l o u t l i n e o f head o f l a r v a (1.0 mm.) F - Antenna o f l a r v a (0.25 mm.) G - L i n g u a and s u p e r l i n g u a o f l a r v a (0.25 mm.) H - P a r a l a b i a l comb o f l a r v a (0.25 mm.) I - T i p o f l a r v a l mandible (0.25 mm.) Procladius denticulatus Sublette J~- Hypopygium o f male imago (0.25 mm.) K - Caudal end o f pupa (1.0 mm.) L - R e s p i r a t o r y organ.of pupa (1.0 mm.) M - P a r a l a b i a l comb o f l a r v a (0.25 mm.) N - S u p e r l i n g u a o f l a r v a (0.25 mm.) P r o c l a d i u s freemani Sublette 0~~- Hypopygium o f male imago (0.25 mm.) P - R e s p i r a t o r y o r g a n o f pupa (1.0 mm.) Q - Caudal end o f pupa (1.0 mm.) R - Antenna o f l a r v a (0.25 mm.) S - L i n g u a and s u p e r l i n g u a o f l a r v a (0.25 mm.) T - P a r a l a b i a l comb o f l a r v a (0.25 mm.) U - T i p o f l a r v a l mandible (0.25 mm.)  159  T  160a  Figure 4 Key c h a r a c t e r s o f t h e M a c r o p e l o p i i n i and the Coelotanypodini  (length of scale l i n e indicated i n parenthesis).  Procladius sp. A A~- Hypopygium o f male imago (0.25 mm.) B - Caudal end o f pupa (1.0 mm.) C - R e s p i r a t o r y o r g a n o f pupa (1.0 mm.) D - P a r a l a b i a l comb o f l a r v a (0.25 mm.) E - S u p e r l i n g u a o f l a r v a (0.25 mm.) Psectrotanypus varius (Fabricius) F - Hypopygium of male imago (0.25 G - Caudal end o f pupa (1.0 mm.) H - R e s p i r a t o r y organ o f pupa (1.0  mm.) mm.)  Clinotanypus sp. A I - Caudal end o f pupa (1.0 mm.) J - R e s p i r a t o r y organ o f pupa (1.0 mm.) K - Antenna of l a r v a (1.0 mm.) L - L i n g u a and s u p e r l i n g u a o f l a r v a (0.25 M - T i p o f l a r v a l mandible (0.25 mm.)  mm.)  160  161a  Figure 5 Key c h a r a c t e r s o f the P e n t a n e u r i n i  (length of s c a l e l i n e  indicated i n parenthesis). Thienemannimyia s p . A A - Hypopygium o f male imago (0.25 mm.) B - R e s p i r a t o r y organ o f pupa (0.25 mm.) C - C a u d a l end o f pupa (1.0 mm.) Zavrelimyia sp. A D - Hypopygium o f male imago (0.25 mm.) E - F o r e t i b i a l s p u r o f male imago (0.25 Zavrelimyia sp. B F - Hypopygium of male imago (0.25 Zavrelimyia sp. C G - R e s p i r a t o r y organ o f pupa (0.25 H - Caudal end o f pupa (1.0 mm.)  mm.)  mm.) mm.)  Pentaneurini sp. A I - L i n g u a and s u p e r l i n g u a o f l a r v a (0.25 J - M a x i l l a r y p a l p u s o f l a r v a (0.25 mm.) Pentaneurini K >L M -  mm.)  sp. B L a t e r a l o u t l i n e o f l a r v a l head (1.2 mm.) Antenna o f l a r v a (0.25 mm.) L i n g u a , s u p e r l i n g u a and p e c t e n o f l a r v a (0.25 mm.) N - T i p o f l a r v a l mandible (0.25 mm.)  161  L  J  162a  Figure 6 Key  c h a r a c t e r s of the P e n t a n e u r i n i  ( l e n g t h of s c a l e l i n e  indicated i n parenthesis). • L a r s i a a c r o c i n c t a (Goetghebuer) A - Hypopygium of male imago (0.25 mm.) B - Apex of hind t i b i a of male, imago (0.25 mm.) C - Pigment p a t t e r n of abdominal t e r g i t e IV of pupa (1.0 mm.) D - R e s p i r a t o r y organ of pupa (0.25 mm.) E - Caudal end of pupa (1.0 mm.) F - Antenna of l a r v a (0.25 mm.) G - L a t e r a l o u t l i n e of head of l a r v a (1.2 mm.) H - Lingua, s u p e r l i n g u a and pecten of l a r v a (0.25 mm.) I - T i p of l a r v a l mandible (0.25 mm.) Ablabesmyia J K L M N 0 P —  m o n i l i s (Linnaeus) Hypopygium of male imago (0.25 mm.) R e s p i r a t o r y organ of pupa (1.0 mm.) Caudal end of pupa (1.0 mm.) Lingua and s u p e r l i n g u a of l a r v a (0.25 mm.) M a x i l l a r y palpus of l a r v a (0.25 mm.) T i p of l a r v a l mandible (0.25 mm.) Dark a p i c a l claws on p o s t e r i o r p r o l e g s of l a r v a (0.25 mm.)  P e n t a n e u r i n i sp. C Q - M a x i l l a r y palpus of l a r v a (0.25 mm.) R - T i p of l a r v a l mandible (0.25 mm.) * Larva t e n t a t i v e l y associated  163a  Figure 7 Key c h a r a c t e r s o f t h e P r o t a n y p i n i (length of scale  line indicated  and t h e O r t h o c l a d i i n i in  parenthesis).  Protanypus sp. A A - Hypopygium o f male imago (0,25 mm.) B - R e s p i r a t o r y o r g a n o f pupa (1.0 mm.) C - T u b e r c l e s on a n t e r i o r end o f pupa (0.25 mm.) D - C a u d a l end o f pupa (1.0 mm.) E - Antenna o f l a r v a (0.25 mm.) F - L a t e r a l o u t l i n e o f l a r v a l head (1.0 mm.) G - L a b i a l p l a t e o f l a r v a (0.25 mm.) H - T i p o f l a r v a l mandible (0.25 mm.) I - A n a l g i l l s of l a r v a (0.25 mm.) T r i s s o c l a d i u s sp. A J - Hypopygium o f male imago (0.25 mm.) K - R e s p i r a t o r y o r g a n o f pupa (0.25 mm.) L - L a t e r a l margin o f segment V I I I o f pupa (0.25 mm.) M - Antenna o f l a r v a (0.25 mm.) N - L a t e r a l o u t l i n e o f l a r v a l head (1.0 mm.) 0 - L a b i a l p l a t e o f l a r v a (0.25 mm.) P - T i p o f l a r v a l mandible (0.25 mm.) Q - P r e m a n d i b l e o f l a r v a (0.25 mm.)  163  164a  Figure 8 Key c h a r a c t e r s o f the O r t h o c l a d i i n i indicated  in  (length of s c a l e  line  parenthesis).  H e t e r o t r i s s o c l a d i u s sp. A A - Hypopygium o f male imago (0.25 mm.) B - R e s p i r a t o r y organ o f pupa (0.25 mm.) C - S p i n e s on c a u d a l margin o f s t e r n i t e V I I I o f male (0.25 mm.) D - Caudal margin o f s t e r n i t e V I I I o f female (0.25 mm.) E - Antenna o f l a r v a (0.25 mm.) F - L a t e r a l o u t l i n e o f l a r v a l head (1.2 mm.) G - L a b i a l p l a t e o f l a r v a (0.25 mm.) H - T i p o f mandible o f l a r v a (0.25 mm.) I - P r e m a n d i b l e o f l a r v a (0.25 mm.) J - A n a l g i l l s o f l a r v a (0.25 mm.) Heterotanytarsus sp. A K - Hypopygium o f male imago (0.25 mm.) L - R e s p i r a t o r y organ o f pupa (0.25 mm.) M - Antenna of l a r v a (0.25 mm.) N - L a t e r a l o u t l i n e o f l a r v a l head (1.2 mm.) 0 - L a b i a l p l a t e o f l a r v a (0.25 mm.) P - P r e m a n d i b l e o f l a r v a (0.25 mm.) Q - A n a l g i l l s o f l a r v a (0.25 mm.) C r i c o t o p u s t r i c i n c t u s (Meigen) R~~- Hypopygium o f male imago (0.25 mm.) S - R e s p i r a t o r y o r g a n o f pupa (0.25 mm.) T - Caudal end o f pupa (1.0 mm.) U - Antenna o f l a r v a (0.25 mm.) V - L a t e r a l o u t l i n e of l a r v a l head (1.2 mm.) W - L a b i a l p l a t e o f l a r v a (0.25 mm.) X - T i p o f l a r v a l mandible (0.25 mm.) Y - P r e m a n d i b l e o f l a r v a (0.25 mm.)  165a  Figure 9 Key c h a r a c t e r s o f t h e O r t h o c l a d i i n i indicated  in  (length  of s c a l e  line  parenthesis).  Psectrocladius sp. A  ~~  A B C D E F G H  -  Hypopygium o f male imago (0.25 mm.) R e s p i r a t o r y o r g a n o f pupa (0.25 mm.) T e r g i t e IV of pupa (1.0 mm.) Caudal end of pupa (1.0 mm.) Antenna of l a r v a (0.25 mm.) L a t e r a l o u t l i n e of l a r v a l head (1.2 mm.) L a b i a l p l a t e of l a r v a (0.25 mm.) T i p o f l a r v a l mandible (0.25 mm.)  Psectrocladius sp. B ~ I - Hypopygium of male imago (0.25 mm.) J - R e s p i r a t o r y o r g a n o f pupa (0.25 mm.) K - T e r g i t e IV of pupa (1.0 mm.) L - Antenna of l a r v a (0.25 mm.) M - L a b i a l p l a t e of l a r v a (0.25 mm.) N - Premandible of l a r v a (0.25 mm.) 0 - A n a l p a p i l l a o f l a r v a (0.25 mm.) P s e c t r o c l a d i u s sp. C P - Hypopygium of male imago (0.25 mm.) ; Q - R e s p i r a t o r y organ of pupa (0.25 mm.) R - S p i n e s on c e n t e r o f t e r g i t e IV o f pupa (0.25 mm.) S - Antenna of l a r v a (0.25 mm.) T - L a b i a l p l a t e of l a r v a (0.25 mm.) U - L a b i a l p l a t e of l a r v a (0.25 mm.) V - Premandible of l a r v a (0.25 mm.) W - A n a l g i l l of l a r v a (0.25 mm.)  165  166a  F i g u r e 10 Key c h a r a c t e r s o f the O r t h o c l a d i i n i indicated  in  (length of scale  line  parenthesis).  Psectrocladius sp. D A - Hypopygium o f male imago (0.25 mm.) B - R e s p i r a t o r y o r g a n o f pupa (0.25 mm.) C - S p i n e s bn c e n t e r o f t e r g i t e IV o f pupa (0.25 mm.) D - Antenna o f l a r v a (0.25 mm.) E - L a t e r a l o u t l i n e of l a r v a l head (1.2 mm.) F - L a b i a l p l a t e o f l a r v a (0.25 mm.) G - T i p of l a r v a l mandible (0.25 mm.) H - P r e m a n d i b l e o f l a r v a (0.25 mm.) I - A n a l g i l l s o f l a r v a (0.25 mm.) Psectrocladius sp. E J - Hypopygium o f male imago (0.25 mm.) K - R e s p i r a t o r y o r g a n of pupa (0.25 mm.) Psectrocladius sp. F L - Hypopygium o f male imago (0.25 mm.) M - R e s p i r a t o r y o r g a n o f pupa (0.25 mm.) N - S p i n e s on c a u d a l margin o f t e r g i t e V I I I o f pupa (0.25 mm.) •Psectrocladius sp. G 0 - Hypopygium o f male imago (0.25 mm.) P - R e s p i r a t o r y o r g a n o f pupa (0.25 mm.) Q - S p i n e s on c a u d a l margin o f t e r g i t e V I I I o f pupa (0.25 mm.) R - Antenna o f l a r v a (0.25 mm.) S - L a t e r a l o u t l i n e o f l a r v a l head (1.2 mm.) T - L a b i a l p l a t e o f l a r v a (0.25 mm.) U - T i p o f l a r v a l mandible (0.25 mm.) V - P r e m a n d i b l e o f l a r v a (0.25 mm.) W - A n a l p a p i l l a of l a r v a (0.25 mm.) * Larva t e n t a t i v e l y associated  166  167a  F i g u r e 11 Key c h a r a c t e r s o f the M e t r i o c n e m i n i ( l e n g t h o f s c a l e indicated  in  parenthesis).  * P a r a k i e f f e r i e l l a c o r o n a t a (Edwards) A - Hypopygium o f male imago (0.25 mm.) B - R e s p i r a t o r y organ o f pupa (0.25 mm.) C - Caudal end o f pupa (0.25 mm.) D - Antenna of l a r v a (0.1 mm.) E - L a b i a l p l a t e o f l a r v a (0.1 mm.) F - T i p o f l a r v a l mandible (0.1 mm.) * P a r a k i e f f e r i e l l a nigra Brundin G - Hypopygium o f male imago (0.25 mm.) H - R e s p i r a t o r y organ o f pupa (0.25 mm.) I - C a u d a l end o f pupa (0.25 mm.) J - Antenna o f l a r v a (0.1 mm.) , K - L a t e r a l o u t l i n e o f head (0.5 mm.) L - L a b i a l p l a t e o f l a r v a (0.1 mm.) M - T i p of l a r v a l mandible (0.1 mm.) N - P r e m a n d i b l e of l a r v a (0.1 mm.) !  •Corynoneura 0 P Q R S T U -  sp. A Hypopygium o f male imago (0.25 mm.) Caudal end of pupa (0.25 mm.) Antenna o f l a r v a (0.25 mm.) L a t e r a l o u t l i n e o f l a r v a l head (0.5 mm.) L a b i a l p l a t e of l a r v a (0.1 mm.) T i p of l a r v a l mandible (0.1 mm.) Spur a t base o f p o s t e r i o r p r o l e g o f l a r v a (0.1 mm.)  *Larva t e n t a t i v e l y associated  line  167  i  r  168a  F i g u r e 12 Key c h a r a c t e r s o f t h e C h i r o n o m i n i ( l e n g t h of s c a l e indicated  line  i n parenthesis).  • H a r n i s c h i a (Cladopelma) g a l a p t e r a Townes A - Hypopygium o f male imago (0.25 mm.) B - C e p h a l i c t u b e r c l e o f pupa (0.25 mm.) C - L a t e r a l margin o f abdominal segment V I I I o f pupa (1.0 mm.) D - Antenna o f l a r v a (0.25 mm.) E - L a b i a l and p a r a l a b i a l p l a t e s o f l a r v a (0.25 mm.) F - L a t e r a l o u t l i n e o f l a r v a l head (1.2 mm.) -  • H a r n i s c h i a (Cladopelma) alphaeus ( S u b l e t t e ) G - Hypopygium o f male imago (0.25 mm.) H - Antenna o f l a r v a (0.25 mm.) I - L a b i a l and p a r a l a b i a l p l a t e s o f l a r v a (0.25 mm.) J - T i p o f l a r v a l mandible (0.25 mm.) K - A n a l g i l l s o f l a r v a (1.2 mm.) • H a r n i s c h i a ( H a r n i s c h i a ) p o t a m o g e t i Townes L~~- Hypopygium o f male imago (0.25 mm.) M - Abdominal t e r g i t e IV (1.0 mm.) N - Antenna of l a r v a (0.25 mm.) 0 - L a t e r a l o u t l i n e o f l a r v a l head (1.2 mm.) P - L a b i a l and p a r a l a b i a l p l a t e s o f l a r v a (0.25 mm.) Q - T i p o f l a r v a l mandible (0.25 mm.) R - P r e m a n d i b l e of l a r v a (0.25 mm.) H a r n i s c h i a ( H a r n i s c h i a ) amachaerus Townes S - Hypopygium o f male imago (0.25 mm.) T - C e p h a l i c t u b e r c l e o f pupa (0.25 mm.) U - Abdominal t e r g i t e IV o f pupa (1.0 mm.) V - S p i n e p a t t e r n on c a u d a l margin o f abdominal t e r g i t e VI o f pupa (0.25 mm.) W - L a t e r a l margin o f abdominal t e r g i t e V I I I o f pupa (0.25 mm.) X - Antenna o f l a r v a (0.25 mm.) Y - L a t e r a l o u t l i n e o f head o f l a r v a (1.2 mm.) Z - L a b i a l and p a r a l a b i a l p l a t e s o f l a r v a (0.25 mm.) AA - T i p o f l a r v a l mandible (0.25 mm.) BB - P r e m a n d i b l e o f l a r v a (0.25 mm.) •Larva t e n t a t i v e l y associated  168  169a  F i g u r e 13 Key c h a r a c t e r s of the Chironomini (length indicated  in  of s c a l e  line  parenthesis).  Crypto ch i ronomus sp. A A - Hypopygium of male imago (0.25 mm.) B - C e p h a l i c t u b e r c l e of pupa (0.25 mm.) C - Abdominal t e r g i t e IV of pupa (2.4 mm.), i n s e r t (0.25 mm.) D - Caudal end o f pupa (1.0 mm.) E - Antenna of l a r v a (0.25 mm.) F - L a t e r a l o u t l i n e o f head of l a r v a (1.2 mm.) : G - L a b i a l and p a r a l a b i a l p l a t e s of l a r v a (0.25 mm.) H - T i p o f l a r v a l mandible (0.25 mm.) I - Premandible of l a r v a (0.25 mm.) J - Anal g i l l s of l a r v a (1.2 mm.) Cryptochironomus sp. B K - Hypopygium of male imago (0.25 mm.) L - C e p h a l i c t u b e r c l e o f pupa (0.25 mm.) M - Abdominal t e r g i t e IV of pupa (1.0 mm.) ) N - Caudal end o f pupa (1.0 mm.) 0 - Antenna of l a r v a (0.25 mm.) P - L a b i a l and p a r a l a b i a l p l a t e s of l a r v a (0.25 mm.) Q - T i p of l a r v a l mandible (0.25 mm.)  169  170a  F i g u r e 14 Key c h a r a c t e r s of the Chironomini (length indicated  in  Pagastiella A B C D E F G H -  of s c a l e  line  parenthesis).  sp. A Hypopygium of male Imago (0.25 mm.) C e p h a l i c t u b e r c l e of pupa (0.25 mm.) Abdominal t e r g i t e IV of pupa (1.0 mm.) L a t e r a l margin o f abdominal segment VIII of pupa (0.25 mm.) Antenna of l a r v a (0.25 mm.) L a t e r a l o u t l i n e of l a r v a l head (1.2 mm.) L a b i a l and p a r a l a b i a l p l a t e s of l a r v a (0.25 mm.) T i p of l a r v a l mandible (0.25 mm.)  M i c r o t e n d i p e s p e d e l l u s (De Geer) I - Hypopygium of male imago (0.25 mm.) J - Abdominal t e r g i t e II of pupa (2.4 mm.) K - L a t e r a l margin of abdominal segment VIII of pupa (1.0 ram.) L - Antenna of l a r v a (0.25 mm.) M - L a t e r a l o u t l i n e of l a r v a l head (1.2 mm.) N - L a b i a l and p a r a l a b i a l p l a t e s o f l a r v a (0.25 mm.) 0 - T i p of l a r v a l mandible (0.25 mm.) Chironomus (Limnochironomus) modestus Say P~~- Hypopygium of male imago (0.25 mm.) Q - C e p h a l i c t u b e r c l e of pupa (0.25 mm.) R - Abdominal t e r g i t e IV of pupa (1.0 mm.) S - L a t e r a l margin of abdominal segment V I I I of pupa (1.0 mm.) T - Antenna of l a r v a (0.25 mm.) U - L a t e r a l o u t l i n e of l a r v a l head (1.2 mm.) V - L a b i a l and p a r a l a b i a l p l a t e s of l a r v a (0.25 mm.) W - T i p of l a r v a l mandible (0.25 mm.)  170  171a  Figure  15  Key c h a r a c t e r s of the Chironomini (length of s c a l e indicated  in  line  parenthesis).  Chironomus (Chironomus) r e m p e l i i Thienemann 7T"- Hypopygium of male imago (0.25 mm.) B - C e p h a l i c t u b e r c l e of pupa (0.25 mm.) C - Abdominal t e r g i t e IV o f pupa (2.4 mm.) D - L a t e r a l margin of abdominal segment VIII of pupa (1.0 mm.) E - Antenna of l a r v a (0.25 mm.) F - L a t e r a l o u t l i n e of l a r v a l head (1.2 mm.) G - L a b i a l and p a r a l a b i a l p l a t e s of l a r v a (0.25  mm.)  H - T i p of l a r v a l mandible (0.25 mm.) I - A n a l g i l l s of l a r v a (1.2 mm.) Chironomus (Chironomus) decorus Johannsen 3T~- Hypopygium of male imago (0.25 mm.) K - C e p h a l i c t u b e r c l e of pupa (0.25 mm.) L - Abdominal t e r g i t e IV of pupa (2.4 mm.) M - L a t e r a l margin of abdominal segment VIII of pupa (1.0 mm.) N - Antenna of l a r v a (0.25 mm.) 0 - L a t e r a l o u t l i n e of l a r v a l head (1.2 mm.) P - T i p of l a r v a l mandible (0.25 mm.) Q - Anal g i l l s of l a r v a (1.2 mm.)  171  172a  F i g u r e 16 Key c h a r a c t e r s of the Chironomini (length of s c a l e indicated  in  line  parenthesis).  P o l y p e d i l i u m (P o l y p e d i l i u m) nubeculosum (Meigen) A - Hypopygium of male imago (TT.25 mm.) B - Abdominal t e r g i t e IV of pupa (1.0 mm.) C - L a t e r a l margin of abdominal segment VIII of pupa (1.0 mm.) D - Antenna of l a r v a (0.25 mm.) E - L a t e r a l o u t l i n e of l a r v a l head (1.2 mm.) F - L a b i a l and p a r a l a b i a l p l a t e s of l a r v a (0.25 mm.) G - T i p of l a r v a l mandible (0.25 mm.) P o l y p e d i l i u m (Pentapedilium) t r i t u m (Walker) H - Hypopygium of male imago (0.25 mm.) I - Abdominal t e r g i t e IV of pupa (1.0 mm.) J - L a t e r a l margin of abdominal segment VIII o f pupa (0.25 mm.) K - Antenna of l a r v a (0.25 mm.) L - L a t e r a l o u t l i n e of l a r v a l head (1.2 mm.) M - L a b i a l and p a r a l a b i a l p l a t e s of l a r v a (0.25 mm.) N - T i p of l a r v a l mandible (0.25 mm.) 0 - Anal g i l l s of l a r v a (0.25 mm.) P o l y p e d i l i u m (Tripodura) simulans Townes P - Hypopygium of male imago (0.25 mm.) Q - Abdominal t e r g i t e IV of pupa (1.0 mm.) R - L a t e r a l margin of abdominal segment VIII of pupa (0.25 mm.) S - Antenna of l a r v a (0.25 mm.) T - L a t e r a l o u t l i n e of l a r v a l head (1.2 mm.) U - L a b i a l and p a r a l a b i a l p l a t e s of l a r v a (0.25 mm.) V - T i p of l a r v a l mandible (0.25 mm.)  172  173a  F i g u r e 17 Key c h a r a c t e r s o f the C h i r o n o m i n i ( l e n g t h o f s c a l e indicated  line  i n parenthesis).  Sergentia A" B C D  sp. A - Hypopygium o f male imago (0.25 mm.) - C e p h a l i c t u b e r c l e of pupa (0.25 mm.) - Abdominal t e r g i t e IV of pupa (1.0 mm.) - L a t e r a l margin o f abdominal segment V I I I o f pupa (1.0 mm.) E - Antenna of l a r v a (0.25 mm.) F - L a t e r a l o u t l i n e o f l a r v a l head (1.2 mm.) G - L a b i a l and p a r a l a b i a l p l a t e s o f l a r v a (0.25 mm.)  T r i b e l o s p r o t e x t u s (Townes) H - Hypopygium o f male imago (0.25 mm.) I - Abdominal t e r g i t e IV o f pupa (1.0 mm.) J - L a t e r a l margin o f abdominal segment V I I I o f pupa (1.0 mm.) K - Antenna o f l a r v a (0.25 mm.) L - L a t e r a l o u t l i n e o f l a r v a l head (1.2 mm.) M - L a b i a l and p a r a l a b i a l p l a t e s o f l a r v a (0.25 mm.) N - T i p of l a r v a l mandible (0.25 mm.)  173  174a  F i g u r e 18 Key c h a r a c t e r s of the T a n y t a r s i n i indicated  (length of s c a l e  line  i n parenthesis).  Z a v r e l i a sp. A A - Hypopygium o f male imago (0.25 mm.) B - R e s p i r a t o r y o r g a n o f pupa (1.0 mm.) C - T e r g i t e IV o f pupa (1.0 mm.) D - L a t e r a l margin o f abdominal segment V I I I o f pupa (0.25 mm.) E - Antenna of l a r v a (0.25 mm.) F - L a b i a l and p a r a l a b i a l p l a t e s of l a r v a (0.25 mm.) G - T i p of l a r v a l mandible (0.25 mm.) Stempellina H I J K L M N 0 -  bausei ( K i e f f e r ) Hypopygium o f male imago (0.25 mm.) R e s p i r a t o r y o r g a n o f pupa (0.25 mm.) T e r g i t e IV o f pupa (1.0 mm.) L a t e r a l margin of abdominal segment V I I I of pupa (0.25 mm.) Antenna o f l a r v a (0.25 mm.) L a t e r a l o u t l i n e o f l a r v a l head (1.2, mm.) L a b i a l and p a r a l a b i a l p l a t e s o f l a r v a (0.25 mm.) P r e m a n d i b l e of l a r v a (0.25 mm.)  •Lundstroemia sp. A P - Hypopygium o f male imago (0.25 mm.) Q - R e s p i r a t o r y o r g a n o f pupa (1.0 mm.) R - Abdominal t e r g i t e s I I - V o f pupa (1.0 mm.) S - L a t e r a l margin o f a b d o m i n a l segment V I I I of pupa (1.0 mm.) T - Antenna o f l a r v a (0.25 mm.) U - L a t e r a l o u t l i n e o f l a r v a l head (1.2 mm.) V - L a b i a l and p a r a l a b i a l p l a t e s o f l a r v a (0.25 mm.) ; W - T i p of l a r v a l mandible (0.25 mm.) •Larva t e n t a t i v e l y  associated  174  175a  F i g u r e 19 Key c h a r a c t e r s o f the T a n y t a r s i n i indicated  in  (length of s c a l e  line  parenthesis).  •Tanytarsus (Tanytarsus) sp. A A - Hypopygium o f male imago (0.25 mm.) B - R e s p i r a t o r y o r g a n o f pupa (0.25 mm.) C - Abdominal t e r g i t e s I I - V I o f pupa (2.4 mm.) D - L a t e r a l margin o f segment V I I I o f pupa (1.0 mm.) E - Antenna o f l a r v a (0.25 mm.) F - L a b i a l and p a r a l a b i a l p l a t e s o f l a r v a (1.0 mm.) G - A n a l g i l l s o f l a r v a (1.0 mm.) -  Tanytarsus (Tanytarsus) sp. B H - Hypopygium o f male imago (0.25 mm.) I - R e s p i r a t o r y o r g a n o f pupa (0.25 mm.) J - Abdominal t e r g i t e s I I t o VI of pupa (2.4 mm.) K - L a t e r a l margin o f segment V I I I o f pupa (1.0 mm.) L - Antenna o f l a r v a (0.25 mm.) M - L a t e r a l o u t l i n e o f l a r v a l head (1.0 mm.) N - L a b i a l and p a r a l a b i a l p l a t e s of l a r v a (0.25 mm.) 0 - T i p o f l a r v a l mandible (0.25 mm.) P - A n a l g i l l s of l a r v a (1.0 mm.) -  •Larva t e n t a t i v e l y associated  175  176a  F i g u r e 20 Key c h a r a c t e r s of the T a n y t a r s i n i indicated  (length of scale  line  i n parenthesis).  Tanytarsus (Tanytarsus) sp. C A - Hypopygium o f male imago (0.25 mm.) B - R e s p i r a t o r y o r g a n o f pupa (1.0 mm.) C - Abdominal t e r g i t e s I I I - V I I of pupa (2.4 mm.) D - L a t e r a l m a r g i n o f segment V I I I (1.0 mm.) E - Antenna o f l a r v a (0.25 mm.) F - L a t e r a l o u t l i n e o f head of l a r v a (1.2 mm.) G - L a b i a l and p a r a l a b i a l p l a t e s o f l a r v a (0.25 mm.) H - T i p o f l a r v a l mandible (0.25 mm.) I - A n a l g i l l s o f l a r v a (1.0 mm.) -  T a n y t a r s u s ( T a n y t a r s u s ) e x c a v a t u s Edwards 1~- Hypopygium o f male imago (0.25  mm.)  Lundstroemia sp. B K - Abdominal t e r g i t e s I I I - V (1.0 mm.) L - L a t e r a l margin o f segment V I I I (1.0 Tanytarsini M .N 0 -  mm.)  sp. A Antenna of l a r v a (0.25 mm.) L a t e r a l o u t l i n e o f l a r v a l head (1.2 mm.) L a b i a l and p a r a l a b i a l p l a t e s of l a r v a (0.25 mm.) P - T i p o f l a r v a l mandible (0.25 mm.) Q - A n a l g i l l s o f l a r v a (1.0 mm.)  176  177a  F i g u r e 21 The wing v e n a t i o n o f s e l e c t e d Marion Lake C h i r o n o midae.  A l l the wings i l l u s t r a t e d a r e from male imagos. S u b f a m i l y Tanypodinae A - P r o c l a d i u s freemani S u b l e t t e B - Ablabesmyia~"monilis (Linnaeus) Subfamily Orthociadinae C - P r o t a n y p u s sp. A D - P s e c t r o c l a d i u s sp. D E - P s e c t r o c l a d i u s * sp. A S u b f a m i l y Chironominae F G H I J  -  M i c r o t e n d i p e s p e d e l l u s (De Geer) Chironomus r e m p e l i i Thienemann P a g a s t i e l l a sp. A T r i b e l o s p r o t e x t u s (Townes) L u n d s t r o e m i a sp. A  177  B  F  178  PROVISIONAL KEYS TO THE CHIRONOMIDAE OF MARION LAKE, BRITISH COLUMBIA MALE ADULTS 1.  C r o s s - v e i n m-cu p r e s e n t ; s t y l e o f hypopygium never d i r e c t e d r i g i d l y backward  2  C r o s s - v e i n m-cu absent; s t y l e may be d i r e c t e d r i g i d l y backward 2(1).  Cross-vein R  2  .  ..  3  p r e s e n t (connects R^ and R 3 2 +  near t h e i r a p i c e s ) ( F i g u r e s 21-A, 21-B) S u b f a m i l y Tanypodinae Cross-vein R  2  absent  ( F i g . 21-C)  Subfamily Orthocladinae ( p a r t ) . . . . . . 3(1).  4  15  Ratio of fore b a s i t a r s u s to fore t i b i a (=L.R.) l e s s than 1.0; s t y l e o f hypopygium folded  inwards Subfamily Orthocladinae (part)  L.R.  16  n e a r l y always g r e a t e r than 1.0; s t y l e  of hypopygium d i r e c t e d r i g i d l y backwards S u b f a m i l y Chironominae 4(2).  29  F o u r t h t a r s a l segments s h o r t and h e a r t shaped; wing membrane w i t h o u t m a c r o t r i c h i a ; v e r y large species C l i n o t a n y p u s s p . A. pp. 35,160 F o u r t h t a r s a l segment t u b u l a r o f l a t e r a l l y compressed  5  179 5(4).  C r o s s - v e i n m-cu connected t o Cu  6  C r o s s - v e i n m-cu connected t o Cuj_..... 6(5).  10  D i s t a n c e from j u n c t i o n o f m-cu w i t h Cu t o the f o r k o f Cu l e s s than 1/3 t h e l e n g t h of  Cui  Tanypus s p . A  pp. 21,159  D i s t a n c e from j u n c t i o n , o f m-cu t o t h e f o r k of Cu about 1/2 t h e l e n g t h o f C u 7(6).  Wing l e n g t h l e s s than 1.7 mm.;  7  x  A.R. 1.5-  1.7; wing membrane w i t h o u t o r w i t h o n l y a few m a c r o t r i c h i a P s i l o t a n y p u s b e l l u s (Loew) Wing l e n g t h g r e a t e r than 2.0 mm.;  pp. 22,159  A.R. 1.4-  2.6; wing membrane w i t h numerous macrotrichia. 8(7).  8  Wing l e n g t h about 3.5 mm.; without  s t y l e o f hypopygium  a posterior projection P r o c l a d i u s sp. A  Wing l e n g t h 2.0-3.0 mm.;  pp.29,160  s t y l e o f hypopygium  with a posterior projection 9(8).  9  C l y p e u s w i t h 11-14 b r i s t l e s ; p o s t e r i o r p r o j e c t i o n o f s t y l e 1/3-1/4 as l o n g as s t y l e P r o c l a d i u s d e n t i c u l a t u s S u b l e t t e pp.24,159 C l y p e u s w i t h 19-30 b r i s t l e s ; p o s t e r i o r p r o j e c t i o n o f s t y l e 1/5-1/6 as l o n g as s t y l e P r o c l a d i u s freemani  S u b l e t t e pp.27,159  180 10(5) .  C extends beyond the j u n c t i o n of 1*4+5 ^y about .twice the l e n g t h of r-m; about 3.5  mm.;  wing l e n g t h  l e g s w i t h dark bands  Psectrotanypus  v a r i u s (Fabr.) pp. 32,160  C does not extend more than the l e n g t h of beyond the j u n c t i o n of 114+5; l e s s than 3.2  w i n  g  r-m  length  mm  11  11(10). Legs w i t h d a r k bands i n c l u d i n g a median band on the t i b i a ;  hypopygium w i t h an "aedeagal  complex" ( F i g . 6-*J) A b l a b e s m y i a m o n i l i s (Linnaeus) Not  pp.45,162  as above  12  1 2 ( 1 1 ) . Base o f s t y l e much e n l a r g e d ; base of c o x i t e w i t h a d i s t i n c t i v e , spinous b a s a l lobe; t i b i a l spurs  elongate  Thienemannimyia sp. A C o x i t e and s t y l e not as above; f o r e  pp.  36,161  tibial  s p u r l y r e shaped 13(12). Wing l e n g t h about 1.65  13 mm.;  t i p of c c o n s i d e r -  a b l y p r o x i m a l of t i p of M L a r s i a a c r o c i n c t a (Goetghebuer) pp.42,162 Wing l e n g t h 2.5-2.8 mm.;  t i p of C d i r e c t l y  above t i p of M  14  14(13). P r e a p i c a l comb of h i n d t i b i a hypopygium as i n F i g u r e  with 7 spines;  5-D  Z a v r e l i m y i a sp. A  pp.38,161  181 P r e a p i c a l comb o f h i n d t i b i a w i t h 5 s p i n e s ; hypopygium  as i n F i g u r e  5-F  Z a v r e l i m y i a sp. B 15(2).  pp. 40,161  B l a c k i s h ; c o x i t e extends beyond  attachment  of s t y l e by about the l e n g t h of s t y l e Protanypus sp. A  pp. 52,163  Brownish orange; c o x i t e does not extend a p p r e c i a b l y beyond j u n c t i o n of s t y l e Prodiamesa sp. A 16(3).  Wing l e n g t h about 2.6 mm.;  m a c r o t r i c h i a on  wing membrane dense H e t e r o t r i s s o c l a d i u s sp. A Wing l e n g t h l e s s than 2.6 mm.  pp. 58,164  and never w i t h  more than a few m a c r o t r i c h i a  17  1 7 ( 1 6 ) . Apex of h i n d t i b i a g r e a t l y e n l a r g e d ; l e n g t h about 1.0  wing  mm.  Corynoneura sp. A pp. 88,167 Apex of h i n d t i b i a not e n l a r g e d 1 8 ( 1 7 ) . A.R.  not more t h a n 1.3 and L.R.  18 not more  than 0.6  19  Not as above  21  1 9 ( 1 8 ) . P r e a p i c a l comb o f h i n d t i b i a w i t h about 8 s p i n e s ; wing membrane w i t h a few macrotrichia,,,,, near apex Heterotanytarsus sp. A  pp. 61,164  P r e a p i c a l comb of h i n d t i b i a w i t h 12-14  spines;  182 wing membrane w i t h o u t m a c r o t r i c h i a 2 0 ( 1 9 ) . A.R.  0.37-0.64; wing l e n g t h 0.85-0.95  P a r a k i e f f e r i e l l a ( s . s.) A.R.  20  coronata  mm.  (Edwards) pp.83,167  1.15-1.24; wing l e n g t h about 1.6  mm.  P a r a k i e f f e r i e l l a ( s . s.) n i g r a B r u n d i n 2 1 ( 1 8 ) . L.R.  about 0.5  pp.86,167  and abdomen w i t h c o n s p i c u o u s  b l a c k and y e l l o w bands Cricotopus t r i c i n c t u s  (Meigen) pp.64,164  Not as above  22  2 2 ( 2 1 ) . P u l v i l l i minute; s t y l e of hypopygium s h o r t , apex v e r y broad and r i g h t  angled  T r i s s o c l a d i u s sp. A pp.56,163 P u l v i l l i l a r g e and rounded; s t y l e not as above... 2 3 ( 2 2 ) . A.R.  l e s s t h a n 1.3;  wing l e n g t h about 1.4  23  mm.  P s e c t r o c l a d i u s sp. E pp.77,166 A.R.  more than 1.4;  wing l e n g t h 1.6  o r more  24  2 4 ( 2 3 ) . P r e a p i c a l comb of h i n d t i b i a w i t h 18 o r more clumped s p i n e s ; A.R.  l e s s than 2.3  25  P r e a p i c a l comb of h i n d t i b i a w i t h 12-14 i n a s i n g l e row;  A.R.  more than 2.1..  2 5 ( 2 4 ) . S c u t e l l u m w i t h 3 o r 4 b r i s t l e s ; apex of r i g h t a n g l e d , A.R.  28 style  g r e a t e r than 1.70  Without above c o m b i n a t i o n 26(25). Middle  spines  26  of c h a r a c t e r s  and h i n d t i b i a each w i t h one  spur;  27 adult  emergence i n the s p r i n g P s e c t r o c l a d i u s sp. A  pp.68,165  183 M i d d l e and h i n d t i b i a each w i t h two s p u r s ;  adult  emergence i n t h e summer P s e c t r o c l a d i u s s p . B pp.70,165 2 7 ( 2 5 ) . Wing l e n g t h g r e a t e r than 2.1 mm.; apex o f s t y l e rounded P s e c t r o c l a d i u s s p . C*pp.72,165 Wing l e n g t h l e s s than 2.1 mm.; apex o f s t y l e angled P s e c t r o c l a d i u s s p . D pp.75,166 2 8 ( 2 4 ) . C l y p e u s w i t h about 12 b r i s t l e s ; a n a l p o i n t minute P s e c t r o c l a d i u s s p . F pp.78,166 C l y p e u s w i t h about 30-35 h a i r s ; a n a l p o i n t cons p i c u o u s and broad P s e c t r o c l a d i u s s p . G pp.80,166 29(3).  Squama w i t h a f r i n g e o f h a i r s ; wing membrane w i t h o r w i t h o u t m a c r o t r i c h i a ; c r o s s - v e i n r-m d e f i n i t e l y o b l i q u e t o t h e d i r e c t i o n o f v e i n 1*4+5 Tribe Chironomini  30  Squama w i t h o u t a f r i n g e o f h a i r s ; wing membrane w i t h m a c r o t r i c h i a ; c r o s s - v e i n r-m almost parallel  t o and n e a r l y c o n t i n u o u s w i t h R4+5 Tribe Tanytarsini...  45  3 0 ( 2 9 ) . F l a g e l l u m o f antenna w i t h 11 segments  31  F l a g e l l u m o f antenna w i t h 13 segments  39  3 1 ( 3 0 ) . A n a l p o i n t broad; s u p e r i o r appendage horn shaped, not covered w i t h m i c r o t r i c h i a ; c u b i t a l f o r k below o r s l i g h t l y beyond r-m; f r o n t a l t u b e r c l e s p r e s e n t . . .  32  184 Without above c o m b i n a t i o n 3 2 ( 3 1 ) . B l a c k ; A.R.  of  characters  5.23-5.58; t a r s a l beard  33  present  Chironomus (Chironomus) r e m p e l i i Thienemann pp.115-171 Brown and green; A.R. without  3.37-3.93; f o r e t a r s u s  a beard  Chironomus (Chironomus) d e c o r u s Johannsen pp. 118,171 3 3 ( 3 1 ) . S u p e r i o r and  i n f e r i o r appendages of hypopygium  l o n g and e n l a r g e d a t t i p s ; b o t h appendages covered  with microtrichia  Chironomus (Limnochironomus) modestus Say pp.112,170 Not 3 4 ( 3 3 ) . A.R.  as above  34  more than 2.70;  s u p e r i o r appendage o v a l o r  square shaped and about as l o n g as  inferior  appendage which has one o r more a p i c a l b r i s t l e s . . . 35 Without above c o m b i n a t i o n 3 5 ( 3 4 ) . C o l o r b l a c k i s h ; A.R. more than 4.0  of  about 3.9;  36  wing l e n g t h  mm.  Cryp t o ch i ro no mus C o l o r g r e e n i s h ; A.R. 3.1—3.5  characters  sp. A, pp.92,169  2.75-3.31; wing l e n g t h  mm. Cryptochironomus sp. B. pp. 94,169  3 6 ( 3 4 ) . Wing l e n g t h 2.6-3.4 mm.;  eyes r e d ; i n f e r i o r appen37  dage p r e s e n t Wing l e n g t h 1.65-2.25 mm.;  i n f e r i o r appendage 38  absent 3 7 ( 3 6 ) . Brownish b l a c k ; wing l e n g t h 3.3-3.4  mm.  185 H a r n i s c h i a (Cladopelma) g a l a p t e r a Townes pp .97,168 Brownish g r e e n ; wing l e n g t h 2.6-2.7 mm. H a r n i s c h i a (Cladopelma) alphaeus ( S u b l e t t e ) pp.99,168 38(36) . S u p e r i o r appendage elongate", apex e n l a r g e d and w i t h 2 s m a l l s p i n e s ; wing l e n g t h 2.05-2.22  mm.  H a r n i s c h i a ( H a r n i s c h i a ) potamogeti Townes pp.101,168 S u p e r i o r appendage minute; wing l e n g t h  1.65-1.70  mm. H a r n i s c h i a ( H a r n i s c h i a ) amachaerus Townes pp.104,168 3 9 ( 3 0 ) . A.R. 3.41-3.93; f o r e femur w i t h a p a t c h o f d a r k backward-directed  s p i n e s about 3/4 o f the way  to t h e d i s t a l end  39  No t as above  40  4 0 ( 3 9 ) . Wing membrane w i t h m a c r o t r i c h i a ; A.R. more than 2.2; L.R. l e s s than 1.26; wing l e n g t h g r e a t e r than 3.4 mm  41  Not w i t h above c o m b i n a t i o n 4 1 ( 4 0 ) . A.R. 2.21-2.50; L.R.  of characters  42  1.05-1.17  S e r g e n t i a s p . A pp. 129,173 A.R. 2.50-2.88; L.R.  1.18-1.25  Tribelos protextus  (Townes) pp. 132,173  4 2 ( 4 0 ) . A.R. 1.69-2.17; c l y p e u s w i t h 23-35 b r i s t l e s  43  A.R. 1.20-1.53; c l y p e u s w i t h 12-17 b r i s t l e s  44  43(40).  G r e e n i s h brown; wing l e n g t h 1.9-2.2 mm.;  wing  membrane w i t h m a c r o t r i c h i a P o l y p e d i l i u m (Pentapedilium)  t r i t u m (Walk.) pp.124,172  186 B l a c k i s h ; wing l e n g t h 2.7-2.9 mm.; without  wing membrane  macrotrichia  Polypedilium  ( P o l y p e d i l i u m ) nubeculosum  (Meigen)  pp. 121,172 4 4 ( 4 2 ) . L.R. 1.33-1.38; base of a n a l p o i n t w i t h two lateral projections Polypedilium  (Tripodura)  s i m u l a n s Townes pp.121,172  L.R. 1.09-1.20; base o f a n a l p o i n t w i t h o u t  two  lateral projections P a g a s t i e l l a s p . A pp . 107,170 45(29).  A n t e n n a l f l a g e l l u m w i t h 10 o r 12 segments; wing l e n g t h l e s s t h a n 1.5 mm  46  A n t e n n a l f l a g e l l u m w i t h 13 segments; wing l e n g t h 47  more t h a n 1.5 mm 4 6 ( 4 5 ) . A n t e n n a l f l a g e l l u m w i t h 10 segments; A.R. 1.191.26; L.R.  1.38-1.56 Z a v r e l i a s p . A pp. 135,174  A n t e n n a l f l a g e l l u m w i t h 12 segments; A.R. 0.660.80; L.R.  1.0-1.13 Stempellina bausei  47(45).  B l a c k ; wing l e n g t h 2.85-3.05 mm.;  ( K i e f f e r ) pp. 138,174 A.R. about  1.72; L.R. 1.20-1.35; t i b i a l combs u n i t e d , w i t h two s p u r s L u n d s t r o e m i a s p . A pp. 142,174 U s u a l l y g r e e n i s h ; wing l e n g t h 1.75-2.60 A.R. 1.09-1.60; L.R. 1.62-2.65; t i b i a l  mm.; combs  187 separate 48(47).  48  Wing l e n g t h 2.3-2.6 mm.;  A.R.  1.40-1.60  T a n y t a r s u s (Tanytarsus) Wing l e n g t h 1.75-2.20 mm.;  sp. A pp.146,175 49  A.R. 1.09-1.33  4 9 ( 4 8 ) . A n a l p o i n t of hypopygium w i t h o u t  a row of o v a l  markings T a n y t a r s u s (Tanytarsus)  e x c a v a t u s Edwards ppj.53,176  A n a l p o i n t w i t h a row o f o v a l markings 50(49). Wing l e n g t h 2.15-2.20 mm.;  50  L.R. 1.62-1.64;  anal  p o i n t narrow, o v a l markings extend about h a l f way t o apex T a n y t a r s u s (Tanytarsus)  s p . C pp.151,176  Wing l e n g t h 1.75-1.94; L.R. 2.0-2.38, a n a l p o i n t broad and o v a l markings extend n e a r l y to apex T a n y t a r s u s (Tanytarsus)  s p . B pp.148,175  PUPAE  1.  R e s p i r a t o r y o r g a n unbranched and u s u a l l y w i t h a s i e v e p l a t e ; a n a l l o b e s each w i t h two l a t e r a l b r i s t l e s or filaments Subfamily  Tanypodinae  R e s p i r a t o r y organs w i t h o u t  sieve plate;  l o b e s each w i t h a t l e a s t 3 m a r g i n a l or filaments  3 anal  bristles 2  188 2(1).  C a u d o - l a t e r a l margin of abdominal segment V I I I w i t h a spur o r comb o r when unarmed  then  r e s p i r a t o r y organ branched and a n a l l o b e s each w i t h 60 o r more m a r g i n a l f i l a m e n t s S u b f a m i l y Chironomidae,,,  27  C a u d o - l a t e r a l margin o f abdominal segment V I I I w i t h o u t a spur o r comb o r i n t h e case o f T r i s s o c l a d i u s w i t h an imbedded s p i n e a t t h e c a u d o - l a t e r a l margins o f segment V I I I and segment V I I as w e l l ; r e s p i r a t o r y organ unbranched; a n a l l o b e s w i t h o r w i t h o u t marg i n a l f i l a m e n t s and u s u a l l y w i t h 3 l a t e r a l o r t e r m i n a l b r i s t l e s each Subfamily Orthocladinae 3(1).  13  A n a l l o b e s reduced, e x t e n d i n g v e r y l i t t l e caudo-lateral tips  past  o f segment V I I I ( F i g . 3  -A) Tanypus s p . A pp. 21,159 A n a l l o b e s e n l a r g e d , at l e a s t h a l f t h e i r beyond c a u d o - l a t e r a l t i p s 4(3).  lengths  o f segment V I I I  4  A n a l l o b e s rounded, w i t h at l e a s t 150 m a r g i n a l hairs C l i n o t a n y p u s s p . A pp. 35,160  5(4).  Not w i t h above c o m b i n a t i o n o f c h a r a c t e r s  5  A n a l l o b e s rounded and f r i n g e d w i t h s p i n e s  6  Anal lobes pointed, w i t h o r without  marginal  189 s p i n e s . ... 6(5).  9  Length 3.6-3.7 mm.; 19-21 m a r g i n a l  a n a l l o b e s each w i t h  spines  P s i l o t a n y p u s b e l l u s (Loew) pp.22,159 L e n g t h 5.8-9.8 mm.;  a n a l l o b e s each w i t h 27-75  marginal spines 7(6).  L e n g t h 8.1-9.8 mm.; marginal  7 a n a l l o b e s each w i t h 61-75  spines P r o c l a d i u s s p . A pp.29,160  Length 5.8-7.1 mm.;  a n a l l o b e s each w i t h 27-53  marginal spines 8(7).  8  A n a l l o b e s each w i t h 27-36 m a r g i n a l  spines  P r o c l a d i u s d e n t i c u l a t u s S u b l e t t e pp.24,159 A n a l l o b e s each w i t h 45-53 m a r g i n a l P r o c l a d i u s freemani 9(5).  spines  S u b l e t t e pp.27,159  A n a l l o b e s w i t h h a i r s on i n n e r and o u t e r margins Psectrotanypus  y a r i u s (Fabr.)  pp.32,160  A n a l l o b e s bare o r w i t h s h o r t s p i n e s 10(9).  10  L a t e r a l margins o f segments I I I - V I each w i t h 6 filaments Thienemannimyia s p . A pp.36,161 L a t e r a l margins of segments I I I - V I bare w i t h f i n e h a i r s but w i t h o u t  11(10). L e n g t h 3.6 mm.;  filaments  a n a l f i n about 1.8 times as  l o n g as b r o a d ; a n t e r i o r h a l f o f abdominal t e r g i t e s w i t h d i s t i n c t dark markings  11  190 L a r s i a a c r o c i n c t a (Goetgh.) pp.42,162 Length 5.3-5.8 mm.;  a n a l f i n 1.2-1.4 times as  l o n g as broad  12  12(11). R e s p i r a t o r y o r g a n o v a l , d a r k brown and w i t h o u t a s i e v e p l a t e ( F i g . 5-K); a n a l l o b e s w i t h s p i n u l e s o n l y on the o u t e r margins A b l a b e s m y i a m o n i l i s (Linnaeus)  pp.45,162  R e s p i r a t o r y organ about 3 times as l o n g as broad ( F i g . 5-G); a n a l l o b e s w i t h s p i n u l e s on both i n n e r and o u t e r margins Z a v r e l i m y i a s p . C pp.41,161 13(2).  L e n g t h at l e a s t 8.0 mm.;  a n a l l o b e s each w i t h 4  t e r m i n a l b r i s t l e s and 4 o r 5 s m a l l e r  lateral  bristles P r o t a n y p u s s p . A pp.52,163 Not as above  14  14(13). A n a l l o b e s each w i t h 3 o r 4 b r i s t l e s and no l a t e r a l filaments or hairs  15  Anal lobes with l a t e r a l f i l a m e n t s o r h a i r s 15(14). Length 5.0-5.5 mm., and w i t h o u t  17  r e s p i r a t o r y organ t u b u l a r  spinules Cricotopus t r i c i n c t u s  Length l e s s than 3.2 mm.;  (Meigen) pp.64,164  r e s p i r a t o r y organ  o v a l ; anal lobes pointed 16(15). L e n g t h 1.6-1.9  16  mm  Parakiefferiella  coronata  (Edwards) pp.83,167  191 Length 2.8-3.1  mm.  Parakiefferiella 1 7 ( 1 4 ) . Length  n i g r a B r u n d i n pp. 86,167  about 1.6 mm.;  a n a l l o b e s each w i t h about  18 l a t e r a l f i l a m e n t s and no t e r m i n a l b r i s t l e s Corynoneura s p . A pp.88,167 Length  a t l e a s t 2.9 mm.;  anal lobes u s u a l l y with  t e r m i n a l b r i s t l e s as w e l l as m a r g i n a l  filaments..18  1 8 ( 1 7 ) . T e r g i t e IV-VI w i t h o u t a p a t c h of c o a r s e s p i n e s near the c e n t e r o f each d i s c ;  respiratory  organs s p i n o u s and p o i n t e d a p i c a l l y ; a n a l l o b e s , each w i t h 16-34 m a r g i n a l f i l a m e n t s and 3 terminal bristles Without above c o m b i n a t i o n o f c h a r a c t e r s  19 21  19(18). C a u d o - l a t e r a l margins o f segments V I I and V I I I each w i t h an imbedded spur T r i s s o c l a d i u s s p . A pp.56,163 Without such s p u r s 2 0 ( 1 9 ) . Length 3.7-4.5 mm.;  20 a n a l l o b e s each w i t h 23-25  m a r g i n a l f i l a m e n t s and 3 t e r m i n a l b r i s t l e s H e t e r o t r i s s o c l a d i u s s p . A pp.58,164 Length 3.0-3.3 mm.;  a n a l l o b e s each w i t h 16-20  m a r g i n a l f i l a m e n t s and 3 t e r m i n a l b r i s t l e s H e t e r o t a n y t a r s u s s p . A. pp. 61,164 2 1 ( 1 8 ) . A n a l l o b e s p o i n t e d ; r e s p i r a t o r y organ bare o r w i t h a few s p i n u l e s a t t i p . . . . A n a l l o b e s rounded; r e s p i r a t o r y o r g a n w i t h s p i n e s  22  192 or scales  23  2 2 ( 2 1 ) . A n a l l o b e s each w i t h 40-51 m a r g i n a l f i l a m e n t s and 3-4 b r i s t l e s ; emergence i n s p r i n g P s e c t r o c l a d i u s s p . A pp.68-165 A n a l l o b e s each w i t h 23-29 m a r g i n a l f i l a m e n t s and 3-5 b r i s t l e s ; emergence i n summer P s e c t r o c l a d i u s s p . B pp.70,165 2 3 ( 2 1 ) . R e s p i r a t o r y organs rounded a p i c a l l y and covered with pointed  s p i n e s ; a n a l l o b e s each w i t h 13-  37 m a r g i n a l f i l a m e n t s ; t e r g i t e s V I I and V I I I w i t h o u t a c a u d a l row o f s p i n e s R e s p i r a t o r y organ pointed  24  a p i c a l l y and w i t h  rounded s c a l e s o r s p i n e s ; a n a l l o b e s each w i t h 40-65 m a r g i n a l f i l a m e n t s ; t e r g i t e s V I I and V I I I w i t h a c a u d a l row o f l o n g s p i n e s 2 4 ( 2 3 ) . L e n g t h 3.0-3.4 mm.;  26  t e r g i t e s IV t o VI each w i t h  a s i n g l e o v a l s p i n e p a t c h and a n a l l o b e s  each  w i t h 13-16 m a r g i n a l f i l a m e n t s and 3 t e r m i n a l bristles P s e c t r o c l a d i u s s p . E pp.77,166 Not as above.  25  2 5 ( 2 4 ) . L e n g t h 4.5-4.8 mm.;  a n a l l o b e s each w i t h 32-37  m a r g i n a l f i l a m e n t s and 3 t e r m i n a l  bristles  P s e c t r o c l a d i u s s p . C pp.72,165 L e n g t h 3.6-4.5 mm.;  a n a l l o b e s each w i t h 21-28  m a r g i n a l f i l a m e n t s and 3 t e r m i n a l  bristles  193 P s e c t r o c l a d i u s s p . D pp.75,166 2 6 ( 2 3 ) . Length about 4.4 mm.;  a n a l l o b e s each w i t h  about 42 m a r g i n a l f i l a m e n t s and 3 c o a r s e terminal  bristles P s e c t r o c l a d i u s s p . F pp.78,166  Length about 5.1 mm.;  a n a l l o b e s each w i t h  about 65 m a r g i n a l f i l a m e n t s and no c o a r s e bristles P s e c t r o c l a d i u s s p . G pp.80,166 27(2).  R e s p i r a t o r y organ w i t h a t l e a s t two b r a n c h e s ; abdominal t e r g i t e s shagreened but u s u a l l y without p a i r e d patches of dark spines o r spinules Tribe Chironomini R e s p i r a t o r y organ i f present simple;  28 abdominal  t e r g i t e s with d i s t i n c t i v e dark patches of spines or spinules Tribe Tanytarsini  43  2 8 ( 2 7 ) . C a u d o - l a t e r a l margin o f segment V I I I w i t h o u t a comb o r spur  29  C a u d o - l a t e r a l margin o f segment V I I I w i t h a comb o r spur  31  2 9 ( 2 8 ) . T e r m i n a l segment w i t h a c o n s p i c u o u s two pronged p r o j e c t i o n ( F i g u r e s 11-D and 11-N) T e r m i n a l segment w i t h o u t a c o n s p i c u o u s two pronged p r o j e c t i o n  30  194 H a r n i s c h i a ( H a r n i s c h i a ) p o t a m o g e t i Townes PP.101,168 3 0 ( 2 9 ) . Length 11.2-12.5 mm.; marginal  a n a l l o b e s each w i t h 100+  filaments Cryptochironomus s p . A pp. 92,169  L e n g t h 7.5-8.3 mm.; 90 m a r g i n a l  a n a l l o b e s each w i t h 60-  filaments Cryptochironomus s p . B pp. 94,169  3 1 ( 2 8 ) . C a u d o - l a t e r a l margin o f segment V I I I w i t h a s i m p l e curved  s p u r o r r a r e l y w i t h one main  s p u r and a s m a l l e r a c c e s s o r y  spine  32  Spur o r comb on segment V I I I w i t h s e v e r a l spines 3 2 ( 3 1 ) . Length 3.9-4.2 mm.;  33 c a u d a l margin o f t e r g i t e  VI w i t h a c o n s p i c u o u s o v a l p a t c h o f c o a r s e spines H a r n i s c h i a ( H a r n i s c h i a ) amachaerus Townes pp.104,168 Length 5.9-7.0 mm.;  c a u d a l margin of t e r g i t e VI  normal Chironomus (Limnochironomus) modestus Say pp.112,170 3 3 ( 3 1 ) . L a t e r a l f i l a m e n t s on segments V t o V I I I 4-4-4-5 o r 4-4-4-4; c a u d o - l a t e r a l margin of segment V I I I w i t h a compound s p u r o r w i t h s p i n e s i n a f a n o r b r u s h - l i k e arrangement; a n a l  lobes  each w i t h more than 60 m a r g i n a l f i l a m e n t s Not w i t h above c o m b i n a t i o n  of c h a r a c t e r s  34 37  195 3 4 ( 3 3 ) . S p i n e s of compound s p u r on segment V I I I o v e r most o f t h e i r l e n g t h ; a n a l l o b e s  united each 35  w i t h more than 84 m a r g i n a l f i l a m e n t s S p i n e s on c a u d o - l a t e r a l margin o f segment V I I I not u n i t e d o v e r most o f t h e i r l e n g t h s and i n a b r u s h - l i k e arrangement; a n a l lobes each w i t h 60-85 m a r g i n a l f i l a m e n t s 3 5 ( 3 4 ) . Length 9.8-10.5 mm.;  a n a l l o b e s each w i t h  36 85-100  marginal filaments Chironomus (Chironomus) decorus Johannsen pp.118,171 Length 11.1-12.0 mm.;  a n a l l o b e s each w i t h 120-  170+ m a r g i n a l f i l a m e n t s Chironomus (Chironomus) r e m p e l i i Thienemann ppj.15,171 3 6 ( 3 4 ) . L e n g t h 7.5-8.1 Harnischia  mm.  (Cladopelma) g a l a p t e r a Townes ppS7,168  Length 6.5-7.0 mm. Harnischia  (Cladopelma) alphaeus ( S u b l e t t e )  pp99,168  3 7 ( 3 3 ) . Comb a t c a u d o - l a t e r a l margin o f segment V I I I composed of 1-4 s h o r t u s u a l l y s e p a r a t e  spines  which a r e about e q u a l i n s i z e ; segment V I I I with 5 p a i r s of l a t e r a l f i l a m e n t s ; anal  fins  each w i t h l e s s than 45 m a r g i n a l f i l a m e n t s Without above c o m b i n a t i o n o f c h a r a c t e r s 3 8 ( 3 7 ) . L e n g t h 3.9-4.9 mm.;  a n a l l o b e s each w i t h 16 o r  fewer m a r g i n a l f i l a m e n t s Pagastiella  s p . A pp.107,170  38 39  196 Length 7.9-8.6 mm.; marginal  a n a l l o b e s each w i t h 35-44  filaments  Microtendipes  p e d e l l u s (De Geer) pp.109,170  3 9 ( 3 7 ) . L a t e r a l f i l a m e n t s on segments V t o V I I I 3-3-4-5; a n a l l o b e s each w i t h more than 50 m a r g i n a l filaments Tribelos protextus  (Townes) pp.132,173  L a t e r a l f i l a m e n t s on segments V t o V I I I 3-3-4-4; , a n a l l o b e s each w i t h l e s s than 50 m a r g i n a l filaments.......  40  4 0 ( 3 9 ) . C e p h a l i c t u b e r c l e s b r o a d l y t r u n c a t e d and w i t h many inward d i r e c t e d s p i n e - l i n e s t r u c t u r e s a t apex; comb on c a u d o - l a t e r a l margin o f segment V I I I v e r y broad S e r g e n t i a s p . A pp.129,173 Not  as above  41  4 1 ( 4 0 ) . C a u d o - l a t e r a l margin o f segment V I I I w i t h a l o n g comb composed of s e v e r a l s t r o n g n e a r l y  equal  spines P o l y p e d i l i u m ( T r i p o d u r a ) s i m u l a n s Townes pp.126,172 C a u d o - l a t e r a l margin.of segment V I I I w i t h main s p i n e s and 2-10+ 4 2 ( 4 1 ) . L e n g t h 6.4-7.2 mm.; marginal  1-5  s m a l l e r ones  a n a l l o b e s each w i t h 31-41  filaments  P o l y p e d i l i u m ( P o l y p e d i l i u m ) ' nubeculosum (Meigen) pp.  121,172  42  197  Length 3.9-4.9 mm.; marginal  a n a l l o b e s each w i t h 21-26  filaments  P o l y p e d i l i u m (Pentapedilium) t r i t u m (Walker) pp.124,172 4 3 ( 2 7 ) . Length 2.8-3.0 mm.;  l a t e r a l margins of segments  V I I I each w i t h 1-4 s p u r s L e n g t h 3.3-7.2 mm.;  44  c a u d o - l a t e r a l margin o f  segment V I I I w i t h a comb composed o f many small spines  45  4 4 ( 4 3 ) . C a u d o - l a t e r a l margin of segment V I I I w i t h a s i n g l e s p u r ; r e s p i r a t o r y organ about mm.  0.45  long Z a v r e l i a s p . A pp.135,174  L a t e r a l margins of segment V I I I each w i t h 3 o r 4 s p u r s ; r e s p i r a t o r y o r g a n about 0.23  mm.  long S t e m p e l l i n a b a u s e i K i e f f e r pp.138,174 4 5 ( 4 3 ) . Abdominal t e r g i t e s IV and V each w i t h one o r two t r a n s v e r s e p a t c h e s of d a r k s p i n u l e s Abdominal t e r g i t e s I I I - V w i t h p a i r e d  46 longi-  t u d i n a l p a t c h e s o f dark s p i n e s o r s p i n u l e s 4 6 ( 4 5 ) . L e n g t h 4.8-7.2 mm.;  a n a l l o b e s each w i t h 54-  67 m a r g i n a l f i l a m e n t s ; abdominal t e r g i t e III with fine spinules L u n d s t r o e m i a s p . A pp. 142,174 L e n g t h 3.6-4.6 mm.;  a n a l l o b e s each w i t h 37-40  marginal f i l a m e n t s ; t e r g i t e I I I with  long  47  198  dark s p i n e s  ' L u n d s t r o e m i a s p . B pp.144,176  4 7 ( 4 5 ) . T e r g i t e s I I I and IV w i t h l o n g b l a c k  spines  Tanytarsus (Tanytarsus)  s p . B pp.148,175  T e r g i t e s I I I and IV w i t h s m a l l s p i n u l e s simi l a r t o those on t e r g i t e s V and VI  48  4 8 ( 4 7 ) . L e n g t h 3.3-4.4 mm.*; a n a l l o b e s each w i t h 24-31 m a r g i n a l f i l a m e n t s ; r e s p i r a t o r y organ p o i n t e d a p i c a l l y and about 0.7 mm.  long  T a n y t a r s u s (Tanytarsus) L e n g t h 4.9-5.7 mm.;  s p . C pp.151,176  a n a l l o b e s each w i t h 33-  41 m a r g i n a l f i l a m e n t s ; r e s p i r a t o r y organ rounded a p i c a l l y and about 0.28 mm. Tanytarsus (Tanytarsus)  long s p . A pp.146,175  LARVAE  1.  Antennae r e t r a c t i l e i n t o head; head l a r g e i n p r o p o r t i o n t o body s i z e ; e y e s p o t s j o i n e d and u s u a l l y r e n i f o r m ( F i g u r e s 3-E, 5-K) Subfamily  Tanypodinae  Antennae not r e t r a c t i l e ; e y e s p o t s or contiguous 2(1).  3 separate  b u t never r e n i f o r m shaped  P a r a l a b i a l p l a t e s , i f present spots separate or contiguous  non s t r i a t e ; eyebut never  r e n i f o r m , v e n t r a l eyespot a n t e r i o r o f d o r s a l  2  one and o f t e n c r e s c e n t shaped Subfamily Orthocladinae S t r i a t e p a r a l a b i a l p l a t e s present; eyespots u s u a l l y s e p a r a t e ; d o r s a l eyespot u s u a l l y above o r a n t e r i o r o f v e n t r a l one, r a r e l y s l i g h t l y b e h i n d i t ; v e n t r a l eyespot may  be  d i v i d e d o r b i l o b e d but never c r e s c e n t shaped S u b f a m i l y Chironominae L i n g u a w i t h 6 l i g h t t e e t h ; antennae o f p r e s e r ved  specimens u s u a l l y extended C l i n o t a n y p u s s p . A pp. 35,160  L i n g u a w i t h 5 ( r a r e l y 4) t e e t h ; antennae u s u a l l y r e t r a c t e d i n s i d e head P a r a l a b i a l combs p r e s e n t ; head l i t t l e  longer  than b r o a d ; antennae about 1/4 as l o n g as head P a r a l a b i a l combs a b s e n t ; head about 1.5-2  times  as l o n g as b r o a d ; antennae about.1/2 as l o n g as head Maximum l e n g t h 7 mm.;  p e c t e n o f hypopharynx  w i t h about 8 t e e t h p e r s i d e ; head 0.46-0.50 mm. in  l o n g i n f o u r t h i n s t a r l a r v a e ; emergence l a t e summer and  fall  P s i l o t a n y p u s b e l l u s (Loew) pp. 22,159 Maximum l e n g t h 16 mm.;  p e c t e n o f hypopharynx  w i t h 11-17 t e e t h p e r s i d e ; head 0.81-1.25  mm.  200 long i n f o u r t h i n s t a r larvae 6(5).  Maximum l e n g t h 16 mm.;  6  p e c t e n o f hypopharynx  w i t h 15-17 t e e t h p e r s i d e ; p a r a l a b i a l combs each w i t h 8-10 d a r k t e e t h ; head 1.12-1.25 mm.  l o n g i n f o u r t h i n s t a r l a r v a e ; emergence  in spring P r o c l a d i u s s p . A pp.29,160 Maximum l e n g t h 10 mm.;  not w i t h r e m a i n i n g com-  b i n a t i o n of characters 7(6).  Head l e n g t h o f f o u r t h i n s t a r l a r v a e mm.;  7 0.81-0.85  emergence i n s p r i n g P r o c l a d i u s f r e e m a n i S u b l e t t e pp.27,159  Head l e n g t h of fourth i n s t a r l a r v e 0.84-0.97  mm.;  emergence i n summer and autumn P r o c l a d i u s d e n t i c u l a t u s S u b l e t t e pp.24,159 8(4).  M a x i l l a r y p a l p u s w i t h one b a s a l segment; b a s a l segment of antenna 0.35-0.40 the l e n g t h of head  9  M a x i l l a r y p a l p u s w i t h 2 o r more b a s a l segments; b a s a l segment o f antenna 0.42-0.54 the l e n g t h of head 9(8).  10  Maximum l e n g t h 5 mm.;  c o l o r green; p e c t e n o f  hypopharynx w i t h 12-13 s p i n e s p e r s i d e L a r s i a a c r o c i n c t a (Goetgh.) pp. 42,162 Maximum l e n g t h 10 mm.;  p e c t e n o f hypopharynx  w i t h 22-26 s p i n e s p e r s i d e  201 P e n t a n e u r i n i s p . A pp. 47,161 10(8).  M a x i l l a r y p a l p u s w i t h 6 b a s a l segments P e n t a n e u r i n i s p . B pp. 48,161 M a x i l l a r y p a l p u s w i t h 2 b a s a l segments  11  1 1 ( 1 0 ) . Head l e n g t h of f o u r t h i n s t a r l a r v a e 0.94-1.06 mm.;  b a s a l segment of antenna 0.42-0.45 the  l e n g t h of head; s e n s o r i u m on d i s t a l h a l f o f a n t e n n a l segment 1 A b l a b e s m y i a m o n i l i s (Linnaeus) pp.45,162 Head l e n g t h of f o u r t h i n s t a r l a r v a e about mm.;  1.18  b a s a l segment o f antenna about 0.54 the  l e n g t h o f head; s e n s o r i u m at t h e m i d d l e o f a n t e n n a l segment 1 P e n t a n e u r i n i sp. C pp. 49,162 12(2).  Caudal margin o f head w i t h a broad b l a c k band ( F i g . 7 - F ) ; e y e s p o t s s i n g l e and c i r c u l a r Pro tanypus s p . A pp. 52,163 Not as above  13  1 3 ( 1 2 ) . Antenna f o u r segmented and at l e a s t as l o n g as head; maximum l e n g t h 4.5 mm... t  14  Antenna f i v e o r s i x segmented and not as l o n g as head  15  1 4 ( 1 3 ) . V e n t r a l margin of head b l a c k ; a n a l g i l l s rounded a p i c a l l y and c o n s t r i c t e d near c e n t e r , a n t e n n a l p r o p o r t i o n s 48:59:8:3 H e t e r o t a n y t a r s u s s p . A pp. 61,164  202  Head u n i f o r m l y l i g h t c o l o r e d ; a n a l g i l l s c o n i c a l and p o i n t e d a p i c a l l y ; a n t e n n a l p r o p o r t i o n s 83:41: 43:2 Corynoneura sp. A pp.  88,167  15(13). A n a l g i l l s rounded a p i c a l l y and c o n s t r i c t e d near c e n t e r ; v e n t r a l p a r t of head b l a c k ; e y e s p o t s u n i t e d and n e a r l y i n a h o r i z o n t a l p l a n e H e t e r o t r i s s o c l a d i u s sp. A pp. Without above c o m b i n a t i o n 16(15). Maximum l e n g t h 3 mm.; Not  58,164  of c h a r a c t e r s  16  eye s p o t s connected  17  as above  18  17(16). L a b i a l p l a t e l i g h t c o l o r e d w i t h a broad median p l a t e and no l a t e r a l t e e t h Parakiefferiella (Parakiefferiella)  coronata  (Edwards) pp. 83,167 L a b i a l p l a t e w i t h a broad p o i n t e d median t o o t h and 6 p a i r s of  laterals  Parakiefferiella pp.  (Parakiefferiella) nigra  Brundin  86,167  18(16). P r e m a n d i b l e b i f i d ; a n a l p a p i l l a w i t h 7 o r 8 a p i c a l b r i s t l e s and w i t h o u t b a s a l s p u r s  19  Premandible s i n g l e ; anal p a p i l l a w i t h 5 a p i c a l b r i s t l e s and u s u a l l y w i t h b a s a l s p u r s  20  19(18). M a n d i b l e b l a c k w i t h f o u r dark l a t e r a l s ; head 0.58-0.70 mm.  long i n f o u r t h i n s t a r larvae  C r i c o t o p u s t r i c i n c t u s (Meigen) pp.64,164  203 M a n d i b l e w i t h a l i g h t a p i c a l and 3 dark head 0.37-0.45 mm.  laterals;  long i n f o u r t h i n s t a r larvae  T r i s s o c l a d i u s sp. A  pp. 56,163  2 0 ( 1 8 ) . A n a l g i l l s t a p e r e d , p o i n t e d a p i c a l l y and about 10 times as l o n g as g r e a t e s t w i d t h ; median t e e t h of l a b i a l p l a t e r e c u r v e d  and d i s t i n c t l y  separ-  ated a t mid l i n e P s e c t r o c l a d i u s s p . D pp. 75,166 A n a l g i l l s r o d l i k e and rounded a p i c a l l y  21  2 1 ( 2 0 ) . A n a l g i l l s about 3 times as l o n g as b r o a d ; a n a l p a p i l l a without b a s a l  spurs  P s e c t r o c l a d i u s s p . C pp. 72,165 A n a l g i l l s a t l e a s t 4 times as l o n g as b r o a d ; anal p a p i l l a with b a s a l spurs  22  2 2 ( 2 1 ) . A n a l g i l l s about 4.5 times as l o n g as broad; f i r s t segment of antenna about 5.5 times as l o n g as second P s e c t r o c l a d i u s s p . G pp. 80,166 A n a l g i l l s a t l e a s t 7 times as l o n g as broad; f i r s t segment of antenna 3.0-3.5 times as l o n g as second 2 3 ( 2 2 ) . Sensorium on b a s a l 2/5 o f a n t e n n a l segment 1; middle teeth of l a b i a l p l a t e l i g h t e r colored and not notched a t mid l i n e P s e c t r o c l a d i u s s p . A pp. 68,165 Sensorium on b a s a l 1/3 o f segment 1; m i d d l e t e e t h  23  204 of l a b i a l p l a t e d a r k and o f t e n weakly notched at mid l i n e P s e c t r o c l a d i u s s p . B pp.70,165 24(2).  Antennae s h o r t , u s u a l l y the b a s a l segment i s l e s s than 1/4 as l o n g as head; i f on t u b e r c l e s then t u b e r c l e s s h o r t e r than wide; l a u t e r b o r n organs u s u a l l y s m a l l and never on l o n g p e t i o l e s ; accessory  t o o t h o f mandible not e x t e n d i n g  beyond a p i c a l t o o t h Tribe Chironomini  25  Antennae l o n g and mounted on prominent t u b e r c l e s t h a t a r e l o n g e r than wide; b a s a l segment o f antenna a t l e a s t 1/4 as l o n g as head; l a u t e r born organs o f t e n on l o n g p e t i o l e s ; a c c e s s o r y t o o t h o f mandible l o n g , e x t e n d i n g apical  beyond  tooth Tribe Tanytarsini  25(24).  40  C e n t r a l p a r t o f l a b i a l p l a t e rounded and l i g h t i n c o l o r ; d o r s a l eyespot c o n s i d e r a b l y  anter-  i o r o f v e n t r a l one; a n a l g i l l s s h o r t and a t least dorsal p a i r pointed Without above c o m b i n a t i o n o f c h a r a c t e r s 26(25).  Maximum l e n g t h 13 mm.;  width of c l e a r c e n t r a l  p a r t o f l a b i a l p l a t e 4.1-5.6 times i n t o w i d t h of l a b i a l p l a t e Cryptochironomus s p . A pp.92,169  26 27  205 Maximum l e n g t h 9 mm.; w i d t h o f c l e a r c e n t r a l p a r t o f l a b i a l p l a t e 3.5-3.6 times i n t o  width  of l a b i a l p l a t e Cryptochironomus s p . B pp.92,169 2 7 ( 2 5 ) . L a b i a l p l a t e w i t h two p a l e median t e e t h ; antenna w i t h 6 segments; e y e s p o t s i n v e r t i c a l contiguous  plane,  o r n e a r l y so Microtendipes  p e d e l l u s (De Geer) pp.109,170  L a b i a l p l a t e u n i f o r m l y c o l o r e d ; antenna w i t h f o u r o r f i v e segments  28  2 8 ( 2 7 ) . V e n t r a l abdominal g i l l s p r e s e n t on segment X I ; a n a l g i l l s l o n g and c u r v e d ; e y e s p o t s w i d e l y separated  29  V e n t r a l abdominal g i l l s absent  30  2 9 ( 2 8 ) . Lower eyespot d i v i d e d o r d i s t i n c t l y b i l o b e d ; v e n t r a l p a i r of anal g i l l s c o n s t r i c t e d at base; maximum l e n g t h 17 mm. Chironomus (Chironomus) decorus Johannsen pp. 118,171 Lower eyespot not d i v i d e d b u t s u r f a c e may be irregular;  a n a l g i l l s not c o n s t r i c t e d a t base;  maximum l e n g t h 22 mm. Chironomus (Chironomus) r e m p e l i i Thienemann pp.115,171 3 0 ( 2 8 ) . L a b i a l p l a t e d a r k w i t h 13 s i m p l e t e e t h ;  antennal  p r o p o r t i o n s 28:8:5:7:3; head w i t h t h r e e  dis-  t i n c t e y e s p o t s ( F i g . 14-U) Chironomus (Limnochironomus) modestus Say pp.112,170  206  Without above c o m b i n a t i o n of c h a r a c t e r s 31(30). With 3 d i s t i n c t  eyespots;  31  l a b i a l plate with  15 l i g h t even t e e t h ; a n t e n n a l p r o p o r t i o n s  53:  16:4:5:2; body r o b u s t H a r n i s c h i a (Cladopelma) g a l a p t e r a Townes pp.97,168 W i t h 2 e y e s p o t s which u s u a l l y are  completely  separate  ,32  3 2 ( 3 1 ) . Antennae mounted on t u b e r c l e s ; l a t e r a l t e e t h of mandible l i g h t c o l o r e d and o f t e n t r u n c a t e d Antennae not on d i s t i n c t  33  tubercles; l a t e r a l  t e e t h of mandible p o i n t e d o r rounded  and  u s u a l l y dark i n c o l o r  35  3 3 ( 3 2 ) . Teeth on the c e n t r a l p a r t of l a b i a l p l a t e t r u n c a t e d and n e a r l y e q u a l i n s i z e  34  Teeth on the c e n t r a l p a r t of l a b i a l p l a t e p o i n t e d and not even i n s i z e H a r n i s c h i a (Cladopelma) alphaeus ( S u b l e t t e ) pp. 99,168 34(33). Tubercle  at base of antenna about t w i c e as l o n g  as  wide; premandible w i t h 5 dark t e e t h ; e y e s p o t s nearly  contiguous  H a r n i s c h i a ( H a r n i s c h i a ) potamogeti Tubercle  Townes pp.101,168  at base of antenna almost as l o n g as  b r o a d ; premandible b i f i d ; e y e s p o t s by about the d i a m e t e r of lower  separated  one  H a r n i s c h i a ( H a r n i s c h i a ) amachaerus Townes pp.104,168  207 3 5 ( 3 2 ) . L a b i a l p l a t e and mandibular p a r e n t ; premandible  t e e t h almost  trans-  t r i f i d ; eyespots w i d e l y  separated P a g a s t i e l l a s p . A pp. 107,170 L a b i a l p l a t e dark 3 6 ( 3 5 ) . Eyespots second  36  i n v e r t i c a l p l a n e and n e a r l y c o n t i g u o u s ; a n t e n n a l segment 1.2-1.4 times as l o n g  as t h i r d segment  37  Eyespots w i d e l y s e p a r a t e d o r v e r y l a r g e and bean shaped; second  a n t e n n a l segment 2 o r more  times as l o n g as t h i r d segment.... 3 7 ( 3 6 ) . Maximum l e n g t h 14 mm.;  38  a n a l g i l l s rounded a p i -  c a l l y and c o n s t r i c t e d near c e n t e r P o l y p e d i l i u m ( P o l y p e d i l i u m ) nubeculosum (Meigen) pp.  121,172  Maximum l e n g t h 7 mm.;  anal g i l l s  long, tapered  and p o i n t e d a p i c a l l y P o l y p e d i l i u m (Pentapedilium) t r i t u m pp.  (Walker)  124,172  38(36). Eyespots  l a r g e , bean shaped, and n a r r o w l y  sep-  a r a t e d ; a n t e n n a l b l a d e about as l o n g as segments 2 t o 5 combined S e r g e n t i a s p . A pp. 129,173 Eyespots s m a l l , round and w i d e l y s e p a r a t e d ; a n t e n n a l b l a d e l o n g e r than segments 2 t o 5 combined  39  208 3 9 ( 3 8 ) . Maximum l e n g t h 14 mm.; a n t e n n a l p r o p o r t i o n s 58: 14:3.5:3.5:2; l a u t e r b o r n organs l a r g e ;  anten-  n a l b l a d e about t w i c e as l o n g as segments 2-5 combined Tribelos protextus Maximum l e n g t h 7 mm.;  (Townes) pp.132,173  a n t e n n a l p r o p o r t i o n s 25:  10:2:8:2; l a u t e r b o r n organs s m a l l ;  antennal  b l a d e about 1.3 times as l o n g as segments 2-5 combined P o l y p e d i l i u m (Tripodura)  simulans  40(24). P a r a l a b i a l p l a t e s widely separated;  Townes pp.126,172 basal  seg-  ment o f antenna 0.25-0.35 as l o n g as head; maximum l e n g t h 3.5 mm  41  P a r a l a b i a l p l a t e s narrowly  separated;  basal  segment o f antenna u s u a l l y a t l e a s t h a l f as l o n g as head; maximum l e n g t h 10 mm 41(40). Lauterborn  organs o p p o s i t e one a n o t h e r a t apex  of segment 2; a n t e n n a l process  42  t u b e r c l e w i t h a palmate  a l o n g median margin S t e m p e l l i n a b a u s e i K i e f f e r pp. 138,174  Lauterborn  organs w i d e l y s e p a r a t e ; one near base  of segment 2 and t h e second near apex o f segment 2; a n t e n n a l t u b e r c l e w i t h a s i m p l e  spur  Z a v r e l i a s p . A p p . 135,174 4 2 ( 4 0 ) . B a s a l segment o f antenna about 1/3 as l o n g as head; l a u t e r b o r n organs l a r g e , l o n g e r than  209  petioles;  a n a l g i l l s curved  s h a r p l y downward  T a n y t a r s i n i s p . A pp. 155,176 Antennae and p e t i o l e s o f l a u t e r b o r n organs longer  43  4 3 ( 4 2 ) . P r e m a n d i b l e b i f i d ; a n a l g i l l s rounded a p i c a l l y and curved mm.  s l i g h t l y downward; head 0.41-0.47  long i n f o u r t h i n s t a r  larvae  L u n d s t r o e m i a s p . A pp.142,174 Premandible t r i f i d ; l e s s than 0.38 mm.  a n a l g i l l s s t r a i g h t ; head long  44  4 4 ( 4 3 ) . F i r s t a n t e n n a l segment about 4 times as l o n g as second segment; a n a l g i l l s rounded a p i c a l l y T a n y t a r s u s (Tanytarsus)  s p . C pp.151,176  F i r s t a n t e n n a l segment 2-3 times as l o n g as second segment; a n a l g i l l s p o i n t e d a p i c a l l y 45(44). Antennal  45  p r o p o r t i o n s 72:25:6:4:2; head about  1.7 times as l o n g as b a s a l segment o f antenna Tanytarsus (Tanytarsus) Antennal  s p . A pp.146,175  p r o p o r t i o n s 88:37:7:3:1.5; head about  1.3 times as l o n g as b a s a l segment of antenna Tanytarsus (Tanytarsus)  s p . B pp.148,175  210  LITERATURE CITED B r u n d i n , L. 1947. Zur k e n n t n i s d e r Schwedischen omiden. A r k . Z o o l . 39A;1-95, 25 p l a t e s .  chiron-  . 1948. Uber d i e metamorphose d e r s e c t i o T a n y t a r s a r i a e C o n n e c t e n t e s . A r k . Z o o l . 41A:1-22. . 1949. Chironomiden und andere b o d e n t i e r e d e r siidschwedischen u r g e b i r g s s e e n . Rep. I n s t . Freshwat. Res. D r o t t n i n g h o l m . 30:1-914. . 1951. Zur k e n n t n i s d e r taxonomie und metamorphose d e r c h i r o n o m i d e n g a t t u n g e n P r o t a n y p u s KIEFF., Prodiamesa KIEFF und monodiamesa KIEFF. Rep. I n s t . F r e s h w a t . Res. D r o t t n i n g h o l m . 33:39-53 . 1956. Zur s y s t e m a t i k d e r O r t h o c l a d i n a e ( D i p t . C h i r o n o m i d a e ) . Rep. I n s t . F r e s h w a t . Res. D r o t t n i n g holm. 37:1-185. Coe, R. L. 1950. Chironomidae. 9(2):121-206.  Handbk. I d e n t . B r . I n s e c t s  C u r r y , L. L. 1958. L a r v a e and pupae of the s p e c i e s of Cryptochironomus ( D i p t e r a ) i n M i c h i g a n . L i m n o l . Oceanogr. 3(4):427-442. Edwards, F. W. 1929. B r i t i s h n o n - b i t i n g midges ( D i p t e r a , C h i r o n o m i d a e ) . T r a n s , e n t . Soc. Lond. 77(11):279-430. F i t t k a u , E. J . 1962. D i e Tanypodinae ( D i p t e r a : C h i r o n o m i d a e ) . Abh. L a r v a l s y s t . I n s e k t e n . Akademie-Verlag, B e r l i n . 453 p. Freeman, P. 1958. A s t u d y o f the Chironomidae ( D i p t e r a ) o f A f r i c a s o u t h o f the Sahara. P a r t IV. B u l l . B r . Mus. nat. H i s t . E n t . 5(9):261-363. . Zool.  1961. The Chironomidae of A u s t r a l i a . 9(4):611-737.  Aust. J .  Hennig, W. 1950. D i e l a r v e n f o r m e n d e r d i p t e r e n . Abh. L a r v a l s y s t . I n s e k t e n . A k a d e m i e - V e r l a g , B e r l i n . 458 p. Johannsen, 0. A. 1937a. A q u a t i c D i p t e r a . P a r t I I I Chironomidae: S u b f a m i l i e s Tanypodinae, Diamesinae, and O r t h o c l a d i n a e . Mem. C o r n e l l U n i v . a g r i c . Exp. S t n . 205:1-84.  211 Johannsen, 0. A. 1937b. A q u a t i c D i p t e r a . P a r t IV Chironomidae. S u b f a m i l y Chironominae. Mem. C o r n e l l U n i v . a g r i c . Exp. S t n . 210:1-56. , and H. K. Townes. 1952. Guide t o t h e i n s e c t s of C o n n e c t i c u t . P a r t IV. The D i p t e r a o r t r u e f l i e s . F i f t h F a s c i c l e : Midges and Gnats. B u l l . Conn. S t . g e o l . n a t . H i s t . Survey 80:1-147. L i n d e b e r g , B. 1964. Nomenclature o f t h e w i n g - v e n a t i o n o f the Chironomidae and o f some o t h e r f a m i l i e s of Nematoc e r o u s D i p t e r a . A n n l s z o o l . f e n n . 1:147-152. M a l l o c h , J . R. 1915.. The Chironomidae, o r midges o f I l l i n o i s , w i t h p a r t i c u l a r reference to the s p e c i e s o c c u r r i n g i n t h e I l l i n o i s R i v e r . B u l l . 111. S t . Lab. nat. H i s t . 10:275-543. M i l l e r , R. B. 1941. A c o n t r i b u t i o n t o t h e e c o l o g y o f t h e Chironomidae o f C o s t e l l o Lake, A l g o n q u i n P a r k , O n t a r i o . P u b i s , Ont. F i s h . Res. L a b . 49:7-63. O l i v e r , D. R. 1959. Some D i a m e s i n i (Chironomidae) from the N e a r c t i c and P a l e a r c t i c . E n t . T i d s k r . 80(1):46-64. . 1963. E n t o m o l o g i c a l s t u d i e s i n t h e Lake Hazen area, Ellesmere Island, i n c l u d i n g l i s t s of species of A r a c h n i d a , C o l l e m b o l a , and I n s e c t a . A r c t i c 16(3):175180. . 1964. A l i m n o l o g i c a l i n v e s t i g a t i o n o f a l a r g e a r c t i c l a k e , N e t t i l l i n g Lake, B a f f i n I s l a n d . Arctic 17(2):69-83. Rempel, J . G. 1936. The l i f e h i s t o r y and morphology o f Chironomus h y p e r b o r e u s . J . B i o l . Bd. Can. 2 ( 2 ) : 2 0 9 TZT.  Roback, S. S. 1957. The immature t e n d i p e d i d s o f t h e P h i l a d e l p h i a a r e a . Monogr. Acad. n a t . S c i . P h i l a d . 9:1-152. . 1959. The subgenus Ablabesmyia and Pentaneura ( D i p t e r a : T e n d i p e d i d a e ; P e l o p i i n a e ) . T r a n s . Am. e n t . Soc. 85:113-135. S u b l e t t e , J . E. 1960. Chironomid midges o f C a l i f o r n i a . I . Chironominae, e x c l u s i v e o f T a n y t a r s i n i (= C a l o p s e c t r i n i ) . P r o c . U. S. n a t n . Mus. 112:197-226. . 1964a. Chironomidae ( D i p t e r a ) o f L o u i s i a n a I . S y s t e m a t i c s and immature s t a g e s o f some l e n t i c c h i r o n omids o f w e s t - c e n t r a l L o u i s i a n a . Tulane S t u d . Z o o l . 11(4):109-150.  212  S u b l e t t e , J . E. 1964b. Chironomid midges o f C a l i f o r n i a . I I . Tanypodinae, Diamesinae, and Podonominae. P r o c . U. S. n a t n . Mus. 115:85-135. Thienemann, A. 1944. B e s t i m m u n g s t a b e l l e n f u r d i e j e t z t bekannten l a r v e n und puppen d e r o r t h o c l a d i i n e n . A r c h . H y d r o b i o l . 39:551-664. Townes, H. K. 1945. The N e a r c t i c s p e c i e s of T e n d i p e d i n i ( D i p t e r a , T e n d i p e d i d a e (=Chironomidae)). Am. M i d i . Nat. 34:1-206.  213 INDEX TO TAXA ABLABESMYIA Johannsen  44  a c r o c i n c t a (Goetghebuer) L a r s i a  42  alphaeus ( S u b l e t t e ) H a r n i s c h i a  99  amachaerus Townes H a r n i s c h i a  104  bausei ( K i e f f e r ) Stempellina  138  b e l l u s (Loew) P s i l o t a n y p u s  22  CHIRONOMINAE  91  CHIRONOMINI  91  CHIRONOMUS Meigen  112  CLINOTANYPUS K i e f f e r  34  Clinotanypus sp. A  35  COELOTANYPODI NI  34  c o r o n a t a (Edwards) P a r a k i e f f e r i e l l a  83  CORYNONEURA W i n n e r t z  88  Corynoneura s p . A  88  CRICOTOPUS van d e r Wulp  64  CRYPTOCHIRONOMUS K i e f f e r  91  Cryptochironomus s p . A  92  Cryptochironomus s p . B  94  decorus Johannsen Chironomus denticulatus Sublette Procladius  118 24  e x c a v a t u s Edwards T a n y t a r s u s  153  freemani Sublette P r o c l a d i u s  27  g a l a p t e r a Townes H a r n i s c h i a  97  HARNISCHIA K i e f f e r  97  214 HETEROTANYTARSUS Sparck  61  Heterotanytarsus sp. A  61  HETEROTRIS SO CLAD I US Sparck  58  H e t e r o t r i s s o c l a d i u s sp. A  58  LARSIA F i t t k a u  41  LUNDSTROEMIA K i e f f e r  141  Lundstroemia sp. A  142  Lundstroemia sp. B  144  MACROPELOPIINI  21  METRIOCNEMINI  83  MICROTENDIPES K i e f f e r  109  modestus Say Chironomus  112  m o n i l i s ( L i n n a e u s ) Ablabesmyia  45  nigra Brundin Parakieff e r i e l l a  86  nubeculosum (Meigen) P o l y p e d i l i u m  121  ORTHOCLADIINI  55  ORTHOCLADINAE  51  PAGASTIELLA B r u n d i n  106  P a g a s t i e l l a sp. A  107  PARAKIEFFERI ELLA Thienemann p e d e l l u s (De Geer) M i c r o t e n d i p e s  83 109  PENTANEURINI  36  Pentaneurini sp. A  47  Pentaneurini sp. B  48  Pentaneurini sp. C  49  POLYPEDELIUM K i e f f e r  121  215 p o t a m o g e t i Townes H a r n i s c h i a  101  PROCLADIUS Skuse  24  P r o c l a d i u s sp. A  29  PROTANYPINI  52  PROTANYPUS K i e f f e r  52  Protanypus sp. A  52  p r o t e x t u s (Townes) T r i b e l o s  132  PSECTROCLADIUS K i e f f e r  67  Psectrocladius sp. A  :  68  Psectrocladius sp. B  70  Psectrocladius sp. C  72  P s e c t r o c l a d i u s sp. D  75  Psectrocladius sp. E  77  P s e c t r o c l a d i u s sp. F  78  Psectrocladius sp. G  80  PSECTROTANYPUS  32  Kieffer  PSILOTANYPUS K i e f f e r  21  r e m p e l i i Thienemann Chironomus  115  SERGENTIA K i e f f e r  129  Sergentia sp. A  129  s i m u l a n s Townes P o l y p e d i l i u m  126  STEMPELLINA Bause  138  TANYPODINAE  .  20  TANYPODINI  .  TANYPUS Meigen Tanypus s p . A  20 20  .  21  216 TANYTARSINI  .  135  T a n y t a r s i n i sp. A  155  TANYTARSUS van d e r Wulp  145  Tanytarsus sp. A  146  Tanytarsus sp. B  148  Tanytarsus sp. C  151  THIENEMANNIMYIA F i t t k a u  36  Thienemannimyia s p . A  36  TRIBELOS Townes  132  t r i c i n c t u s Meigen C r i c o t o p u s  64  TRISSOCLADIUS K i e f f e r  55  T r i s s o c l a d i u s sp. A  56  t r i t u m (Walker) P o l y p e d i l i u m varius (Fabricius) Psectrotanypus  124 32  ZAVRELIA K i e f f e r  135  Z a v r e l i a sp. A  135  ZAVRELIMYIA F i t t k a u  38  Zavrelimyia sp. A  38  Zavrelimyia sp. B Zavrelimyia sp. C  .  40 41  

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