UBC Theses and Dissertations

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UBC Theses and Dissertations

A contribution to the ephemeroptera of British Columbia Filmer, Norman John 1964

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A C O N T R I B U T I O N T O T H E E P H E f f l E R O P T E R A O F B R I T I S H C O L U M B I A by NORMAN JOHN FILMER 8 . 5 c , U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1958 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF Mast e r o f S c i e n c e i n t he Department of Zoology 'die 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 the r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA October, 1964. In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the r e q u i r e m e n t s f o r an advanced degree a t the U n i v e r s i t y of B r i t i s h C o l u m b i a , I a g r e e . t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g of t h i s t h e s i s f o r s c h o l a r l y purposes may be g r a n t e d by the Head of my Department or by h i s r e p r e s e n t a t i v e . I t i s u n d e r s t o o d t h a t c o p y i n g or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n c i a l g a i n . s h a l l not bs a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . A B S T R A C T T h i s t h e s i s i s an amalgamation o f and a c o n t r i b u t i o n t o the knowledge o f the Ephemeroptera o f B r i t i s h C o l u m b i a , an o r d e r which has been l a r g e l y n e g l e c t e d i n Canada, and p a r t i c u l a r l y i n t h i s p r o v i n c e . The t h r e e f a m i l i e s H e p t a g e n i i d a e , Ephemeridae, and B a e t i d a e a r e r e p l a c e d by the f i v e s u p e r f a m i l i e s H e p t a g e n i o i d e a , L e p t o p h l e b i o i d e a , C a e n o i d e a , Ephemeroidea, and P r o s o p i s t o m a t o i d e a p roposed by Edmunds and T r a v e r ( 1 9 5 4 ) . 146 s p e c i e s i n 23 genera have been r e c o r d e d i n B r i t i s h C o l u m b i a . Of t h e s e , 62 as y e t u n i d e n t i f i e d s p e c i e s a r e d e s i g n a t e d by number. A c h e c k l i s t of a l l r e c o r d e d s p e c i e s , and keys and d e s c r i p t i o n s o f t a x o n o m i c a l l y . i m p o r t a n t c r i t e r i a o f t h e s p e c i e s and h i g h e r r a n k s a r e i n c l u d e d h e r e i n . A p r e l i m i n a r y i n v e s t i g a t i o n o f the e c o l o g y of the nymphs c o l l e c t e d by the a u t h o r i n the A l o u e t t e R i v e r and by Dr. G.G.E. Scudder i n the l a k e s o f the C h i l c o t i n , C a r i b o o , and N i c o l a V a l l e y r e g i o n s r e v e a l e d no " p r e f e r e n c e " o f the nymphs f o r the m i d d l e o r edges o f the r i v e r o r f o r p a r t i c l e s i z e o f the s u b s t r a t e . An a c c u r a t e d e t e r m i n a t i o n o f the l a t t e r , however, i s not o b t a i n a b l e w i t h the type o f c o l l e c t i n g equipment employed d u r i n g t h i s s t u d y . Some " p r e f e r e n c e " was shown by a number of s p s c i e s f o r s p e c i f i c r a t e s of c u r r e n t f l o w . No c o r r e l a t i o n between the s p e c i e s o f nymphs and the pH o r the s a l i n i t y o f the environment was d e t e r m i n e d . S u g g e s t i o n s a r e put f o r w a r d f o r the e x t e n s i o n o f our knowledge of t h e taxonomy, e c o l o g y , and b i o l o g y o f the Ephemeroptera. - i v -I w i s h t o e x p r e s s my i n d e b t e d n e s s to Dr. K. Graham, Dr. R.A. R i n g , and Dr. G.G.E. Scudder of the Department o f Zoology of the U n i v e r s i t y o f B r i t i s h Columbia f o r t h e i r v e r y h e l p f u l c r i t i c i s m s and encouragement d u r i n g the p r e p a r a t i o n of t h i s t h e s i s . I am e s p e c i a l l y g r a t e f u l t o Dr. Scudder, who i s r e s p o n s i b l e f o r my i n t e r e s t i n the Ephemeroptera, f o r s u p e r -v i s i n g my work, f o r making a v a i l a b l e t o me h i s own c o l l e c t i o n and t h a t o f t h e U n i v e r s i t y , and f o r p r o v i d i n g me w i t h i n s p i r a t i o n . I would a l s o l i k e to s i n c e r e l y thank Dr. G.F. Edmunds and Dr. R.K. A l l e n of the U n i v e r s i t y of Utah f o r i d e n t i f y i n g the nymphs of my own c o l l e c t i o n , and Dr. T.G. N o r t h c o t e of the U n i v e r s i t y o f B r i t i s h Columbia f o r making a v a i l a b l e t o me the c o l l e c t i n g equipment used d u r i n g t h i s s t u d y . I would l i k e to e x p r e s s a s p e c i a l t h anks to fflr. G.3. Spencer of t h i s u n i v e r s i t y f o r p r o v i d i n g me w i t h the thorough taxonomic f o u n d a t i o n n e c e s s a r y t o the accomplishment of t h i s t h e s i s . - i t -T A B L E O F C O N T E N T S P a, £ a I . Acknowledgements i v . I I . I n t r o d u c t i o n ' 1 I I I . m a t e r i a l s and Methods 4 IV. C h e c k l i s t o f B r i t i s h Columbia Ephemeroptera 12 V. A s y s t e m a t i c a c c o u n t of the a d u l t s and nymphs of the B r i t i s h C o l umbia Ephemeroptera 20 V I . D i s c u s s i o n and C o n c l u s i o n s - 211 V I I . Summary 216 V I I I . L i t e r a t u r e C i t e d 218 - i i i -L I_ 5 T £ £ J. L L. U S T R A. T I 0 N S £ a £ £ PL.ATL\ I 222 F i g . 1. A diagram o f the main t o p o g r a p h i c f e a t u r e s of a m a y f l y wing (based on a f o r e wing o f < j r o n o p s i s permagnus). F i g . 2. R e p r e s e n t a t i v e mouthparts of the m a y f l y nymph. PLATE I I F i g . 3. fflale . g e n i t a l i a of some Heptagenine and B a e t i d nymphs. 223 The o r d e r Ephemeroptera r e p r e s e n t s a major taxonomic group of i n s e c t s of c o n s i d e r a b l e e c o l o g i c a l i n t e r e s t and economic i m p o r t a n c e . T h e i r taxonomy has been f o r the most p a r t n e g l e c t e d i n Canada. T h i s n e g l e c t r e p r e s e n t s an impediment to any sound b i o l o g i c a l work i n which i t i s n e c e s s a r y t o d e f i n e the m a t e r i a l and d i f f e r e n t i a t e between l i f e f o r m s . Many w o r k e r s i n the U n i t e d S t a t e s have p u b l i s h e d taxonomic r e v i e w s of the Ephemeroptera of t h e i r p a r t i c u l a r r e g i o n s , a l t h o u g h t h e r e has been a s c a n t amount p u b l i s h e d i n the p a s t t e n y e a r s . A.E. E a t o n (1883-1888, 1901) p i o n e e r e d t h e study on t h i s c o n t i n e n t . P r o b a b l y the most p r o l i f i c c o n t r i b u t o r t o the taxonomy of t h i s o r d e r was 3, McDunnough, who p u b l i s h e d a g r e a t many papers on the N o r t h America s p e c i e s over a twenty year p e r i o d e n d i n g i n 1943. Some of the more i m p o r t a n t workers i n t h i s f i e l d a r e UJ.Ui. U p h o l t (1936, 1937) and U.K. Mayo (1951, 1952) on the West C o a s t ; UJ.C. Day (1954, 1955) i n C a l i f o r n i a ; H.T. S p i e t h (1941, 1947), N o r t h America i n g e n e r a l ; L. Berner (1956) i n F l o r i d a ; and B.D. Burks (1946, 1949, 1953) i n I l l i n o i s . The o n l y comprehensive s t u d y of t h i s o r d e r i n N o r t h America i s the e x c e l l e n t volume, The B i o l o g y of M a y f l i e s , by 3.G.' Needham,' 3.R. T r a v e r , and Y i n - C h i Hsu i n 1935. The most i m p o r t a n t workers a t p r e s e n t are G.F. Edmunds, 3.R. T r a v e r , and R.K..-'Allen, Edmunds and T r a v e r ( 1 9 5 4 ) , Edmunds (1962) have r e v i s e d t h e taxonomy of the o r d e r , r e p l a c i n g the o r i g i n a l t h r e e f a m i l i e s w i t h f i v e s u p e r f a m i l i e s . Edmunds and T r a v e r (1959, 1963) are a t p r e s e n t r e v i s i n g the Genus E p h e m e r e l l a . Very l i t t l e has been done on the Canadian Ephemeroptera. F.P. Ide (1954) has -2-done a l a r g e amount of mark on the O n t a r i o Ephemeropterans. C o n t r i -b u t i o n s i n t h a t p r o v i n c e have a l s o been made by lil.ffl. S p r u l e s ( 1 9 4 7 ) , The o r d e r has not been i n v e s t i g a t e d a t a l l i n the r e s t o f the c o u n t r y , i n c l u d i n g B r i t i s h C o l u m b i a . The Ephemeroptera i s a p a r t i c u l a r l y s a t i s f a c t o r y group w i t h which t o work, f o r a l t h o u g h the members are f r a g i l e , they e x h i b i t e x c e l l e n t m o r p h o l o g i c a l c r i t e r i a . These i n c l u d e body form, wing v e n a t i o n , the p r o p o r t i o n s o f the l e g segments, g e n i t a l i a and c o l o u r p a t t e r n i n the a d u l t s ; and body form, mouth p a r t s , g i l l s and c o l o u r p a t t e r n i n t h e nymphs. There i s , however, a d i f f i c u l t y , p a r t i c u l a r l y i n the c o n s t r u c t i o n o f k e y s , i n t h a t the a d u l t s o f the s e i n s e c t s e x h i b i t c o n s i d e r a b l e s e x u a l dimorphism, which i s m a n i f e s t e s p e c i a l l y i n the c o l o u r , l e g segment p r o p o r t i o n s , and wing v e n a t i o n . An a t t e m p t has been made i n the f o l l o w i n g keys t o m i n i m i z e t h i s d i f f i c u l t y wherever p o s s i b l e by employing c o u p l e t s which do not c o n s i d e r c o l o u r , l e g segment p r o p o r t i o n s , and wing v e n a t i o n i n t h o s e groups d i s p l a y i n g a marked s e x u a l dimorphism i n t h e s e c r i t e r i a . The use of g e n i t a l i a as a taxonomic f e a t u r e i s k e p t to a minimum because t h e i r use p r e s e n t s t e c h n i c a l d i f f i c u l t i e s and i n c o n v e n i e n c e to t h o s e who may w i s h t o employ the key. However i t i s i m p o s s i b l e t o e l i m i n a t e t h e s e c h a r a c t e r i s t i c s e n t i r e l y . The c o n s i d e r a b l e v a r i a t i o n i n body form of the nymphs among the v a r i o u s s p e c i e s a f f o r d s an e x c e l l e n t o p p o r t u n i t y to s t u d y the r e l a t i o n s h i p between t h e i r morphology and e c o l o g y . - 3 -B r i t i s h Columbia i s a p a r t i c u l a r l y c o n v e n i e n t a r e a f o r the s t u d y of the Ephemeroptera, due t o the d i v e r s i t y o f the e c o l o g i c a l z o n e s , the abundance and a c c e s s i b i l i t y o f l a k e s and r i v e r s , and the number of a v a i l a b l e specimens i n the c o l l e c t i o n o f the U n i v e r s i t y o f B r i t i s h C o l u m b i a . The p r e s e n t s t u d y was t h e r e f o r e u n d e r t a k e n to c l a r i f y the taxonomy o f t h e Ephemeroptera of B r i t i s h C olumbia c o n s i s t e n t w i t h the newer i d e a s o f taxonomy o f t h i s group. I n c l u d e d are a c h e c k l i s t o f a l l s p e c i e s r e c o r d e d from t h e p r o v i n c e , keys o f a d u l t s and nymphs, d e s c r i p t i o n s of t h e c h a r a c t e r i s t i c s o f taxonomic i m p o r t a n c e , and where p o s s i b l e , some ac c o u n t of t h e i r e c o l o g y . For a d i s c u s s i o n of t h e v e r y i n t e r e s t i n g l i f e h i s t o r y o f the m a y f l i e s , and f o r an e v a l u a t i o n o f t h e i r economic i m p o r t a n c e , e s p e c i a l l y as a s o u r c e o f f i s h f o o d , I r e f e r the r e a d e r t o the v e r y e x c e l l e n t a c c o u n t s of Needham, T r a v e r , and Hsu ( 1 9 3 5 ) . -4~ M A T E R I A L S A N D M E T H O D S The m a t e r i a l examined d u r i n g t h i s s t u d y came from t h r e e s o u r c e s , my own c o l l e c t i o n s on the A l o u e t t e R i v e r near Haney, B r i t i s h C o l u m b i a , the c o l l e c t i o n s of Dr. G.G.E. Scudder from l a k e s i n the C h i l c o t i n , C a r i b o o , and N i c o l a V a l l e y r e g i o n s , and the s p i r i t c o l l e c t i o n of nymphs and the c o l l e c t i o n of p i n n e d a d u l t s o f the U n i v e r s i t y of B r i t i s h C o l u m b i a . • A l l specimens from t h e s e t h r e e s o u r c e s were examined and i d e n t i f i e d o r d e s c r i b e d . The system o f c l a s s i f i c a t i o n employed i n t h i s paper i s t h a t proposed by G.F. Edmunds and 3.R. T r a v e r , i n which the t h r e e f a m i l i e s H e p t a g e n i i d a e , Ephemeridae, and B a e t i d a e are r e p l a c e d by the s u p e r f a m i l i e s H e p t a g e n i o i d e a , L e p t o p h l e b i o i d e a , C a e n o i d e a , Ephemeroidea, and P r o s o p i s t o m a t o i d e a . A l l e x c e p t the l a s t a re r e p r e s e n t e d i n B r i t i s h C o l u m b i a . An a t t e m p t was made t o i n v e s t i g a t e the e c o l o g i c a l r e l a t i o n -s h i p s of the nymphs c o l l e c t e d i n the A l o u e t t e R i v e r . T h i s r i v e r was chosen because of i t s p r o x i m i t y t o Vancouver, i t s a c c e s s i b i l i t y , and the v a r i o u s t y p e s of h a b i t a t s i t a f f o r d s from i t s headwaters to i t s mouth. The r i v e r i s d i v i d e d i n t o two arms, the N o r t h and the S o u t h . The former d r a i n s M a r i a n Lake, r u n n i n g f o r a p p r o x i m a t e l y t e n m i l e s to meet the South arm, which runs a t e n m i l e c o u r s e from A l o u e t t e Lake. The r i v e r , then f l o w s a p p r o x i m a t e l y two m i l e s t o empty i n t o the P i t t R i v e r . The w i d t h of the r i v e r v a r i e s from twenty f e e t a t t h e headwaters to s e v e n t y - f i v e f e e t near the mouth. The r a t e of f l o w and c h a r a c t e r of the s t r e a m v a r i e s , b e i n g g e n e r a l l y f a s t e r and more t u r b u l e n t near the o r i g i n s and slow and p l a c i d near - 5 -the mouth. There a re a l s o s t a g n a n t and q u i e t ponds and bac k w a t e r s a l o n g the l e n g t h of t h e r i v e r . The c h a r a c t e r o f the stream bed v a r i e s from the r o c k s and b o u l d e r s o f the headwaters t o mud and s i l t near the mouth. Areas o f g r a v e l and sand a re a l s o p l e n t i f u l and always i n c l o s e a s s o c i -a t i o n w i t h l a r g e r r o c k s . V e g e t a t i o n i n the r i v e r i s s p a r s e , and c o n s i s t s f o r the most p a r t o f v a r i o u s t y p e s o f mosses. At the b e g i n n i n g o f fflay 1959 the r i v e r was mapped and the c h a r a c t e r o f f l o w and the stream bed a t a l l a c c e s s i b l e p o i n t s was n o t e d . Twenty-two of t h e s e p o i n t s were c h o s e n , c a r e b e i n g t a k e n to u t i l i z e as many d i f f e r e n t t y p e s o f h a b i t a t s as p o s s i b l e . These were d i v i d e d i n t o t h r e e groups o f s t a t i o n s , and each week c o l l e c t -i o n s were made from one group, so t h a t each s t a t i o n was v i s i t e d e v e r y t h r e e weeks. D u r i n g the w i n t e r , from September to May, each s t a t i o n was v i s i t e d e v e r y s i x weeks. At each s t a t i o n c o l l e c t i o n s were made from one t o f o u r h a b i t a t s , u s u a l l y t he m i d d l e arid edge o f the r i v e r , and any ba c k w a t e r s or ponds. The edge of t h e r i v e r was c o n s i d e r e d to be t h a t p o r t i o n a c c e s s i b l e by a d i p n e t m a n i p u l a t e d from the bank. The components of the stream bed were d i v i d e d f o r d e s c r i p t i v e p u r p o s e s i n t o e i g h t t y p e s , based on ap p r o x i m a t e p a r t i c l e s i z e -mud, sand, f i n e g r a v e l ( p a r t i c l e s up to 5mm. i n s i z e ) , c o a r s e g r a v e l ( p a r t i c l e s from 6mm. to 2cm. i n s i z e ) , s m a l l r o c k s (from 2cm. to 12cm. i n s i z e ) , l a r g e r o c k s (any r o c k l a r g e r t h a n 12cm. but r e m o v a b l e ) , b o u l d e r s (any immovable r o c k ) , and bedr o c k . -6-The s w i f t n e s s of t h e c u r r e n t i n most l o c a t i o n s p r o h i b i t e d the measurement of c u r r e n t speed w i t h a c u r r e n t meter. T h e r e f o r e i n l i e u o f more a c c u r a t e measurement of r a t e of f l o w , the f o l l o w i n g d e s c r i p t i v e p h r a s e s are used: q u i e t or s t i l l , s low ( a p e r c e p t i b l e c u r r e n t but w i t h o u t r i p p l e s ) , slow r i p p l e s , f a s t r i p p l e s , and r a p i d ( w i t h t u r b u l e n t , w h i t e w a t e r ) . (Iflost c o l l e c t i n g was done w i t h an o r d i n a r y d i p n e t , a l t h o u g h i n some c a s e s a S u r b e r Sampler (Needham and U s i n g e r , 1956) was used. In deep w a t e r near the mouth o f t h e r i v e r , an Ekman dredge was l o w e r e d from v a r i o u s b r i d g e s . The m a t e r i a l c o l l e c t e d was brought i n t o the l a b o r a t o r y , c o u n t e d , i d e n t i f i e d t o f a m i l y o r o r d e r , and p r e s e r v e d i n a l c o h o l f o r more a c c u r a t e i d e n t i f i c a t i o n a t a l a t e r d a t e . A b r i e f d i s c u s s i o n a t t h i s p o i n t o f the taxonomic f e a t u r e s of the Ephemeroptera might b e n e f i t r e a d e r s u n f a m i l i a r w i t h the o r d e r . A l t h o u g h t h e r e i s c o n s i d e r a b l e v a r i a t i o n i n morphology among th e v a r i o u s s p e c i e s and among h i g h e r r a n k s , the m o r p h o l o g i c a l d e t a i l s a r e r e m a r k a b l y c o n s t a n t w i t h i n a s p e c i e s . The body form o f t h e a d u l t v a r i e s from l o n g and s l e n d e r to s h o r t and t h i c k . The antennae a r e s h o r t and s e t a c i o u s . The compound eyes are u s u a l l y l a r g e r i n the male than i n the f e m a l e , and may be a p p r o x i m a t e d a p i c a l l y i n the f o r m e r . In some groups the d o r s a l p o r t i o n s a r e l i g h t e r i n c o l o u r t h a n the v e n t r a l p o r t i o n s , as i n the genera S i p h l o n u r u s and H e p t a q e n i a . The eyes i n the genera B l a s t u r u s and E p h s m e r e l l a are d i v i d e d i n t o a l a r g e r , l i g h t e r upper p o r t i o n and a s m a l l e r , d a r k e r l o w e r p o r t i o n by a t r a n s v e r s e g r o o v e , and i n a l l the B a e t i n a e the eyes a r e c o m p l e t e l y d i v i d e d , the upper p o r t i o n b e i n g t u r b i n a t e . A l l s p e c i e s have t h r e e o c e l l i , a r r a n g e d t o form a t r i a n g l e , t he d i s t a n c e s between them v a r y i n g . The wings are not f r a g i l e , as b e f i t s an i n s e c t t h a t spends the major p a r t o f i t s a d u l t l i f e i n the a i r . They are s t r o n g l y a t t a c h e d t o a w e l l - d e v e l o p e d t h o r a x which c o n t a i n s the p o w e r f u l muscles o f f l i g h t . They are u s u a l l y h y a l i n e , b u t may be t i n t e d brown or amber, or s u f f u s e d w i t h b r o w n i s h or b l a c k i s h c l o u d s . The v e n a t i o n i s p a l e o r d a r k . The f o r e w i n g s a r e l a r g e , f a n - s h a p e d , and f l u t e d . They can be d i v i d e d i n t o t h r e e a r e a s , the c o s t a l s t r i p , the m i d d l e f i e l d , and the a n a l a r e a . The t h r e e s t r o n g v e i n s , the c o s t a , the s u b c o s t a and the f i r s t branch of the r a d i u s o c c u p y i n g the c o s t a l s t r i p a r e s t r e n g t h e n e d by a c o s t a l b r a c e near the wing base. These v e i n s may be broken a t t h e i r m i d p o i n t s by a b u l l a , p r o v i d i n g g r e a t e r f l e x i b i l i t y . The v e n a t i o n of the m i d d l e f i e l d c o n s i s t s o f the r a d i a l s e c t o r and media, b o t h of which a r e f o r k e d a l m o s t a t t h e i r b a s e s . The a n t e r i o r b ranch o f the r a d i a l s e c t o r i s d i c h o t o m o u s l y f o r k e d f a r t h e r o u t , and i t s p o s t e r i o r branch i s f o r k e d to form the " o u t e r f o r k " ( O f ) . O f t e n t h e s e f o r k s and the i n t e r c a l a r i e s between them form " t r i a d s " . The a n a l a r e a c o n t a i n s the c u b i t u s , which i s d i v i d e d t o i t s base, and s e v e r a l s h o r t a n a l v e i n s . The f l u t i n g o f the w i n g s , caused by the c o n v e x i t y and c o n c a v i t y of the v e i n s and t h e i r b r a n c h e s , i s c o n s t a n t and d i s t i n c t . T h i s i s an a i d to i d e n t i f i c a t i o n when the f o r k s become detached and appear t o be i n t e r c a l a r i e s - . C r o s s v e i n s a r e numerous, and s e r v e t o s t r e n g t h e n the f l u t e d arrangement of the l o n g i t u d i n a l v e i n s . They a r e p a r t i c u l a r l y s t r o n g i n the s t i g m a t i c a r e a , and may be reduced or w a n t i n g i n the b a s a l c o s t a l a r e a i n the more s p e c i a l i z e d s p e c i e s . M a r g i n a l v / e i n l e t s , v a r y i n g i n number and form, may be p r e s e n t i n some g e n e r a . The h i n d wings are s m a l l e r t h a n the f o r e w i n g s , and v a r y i n shape. They become s m a l l e r w i t h s p e c i a l i z a t i o n , and may be absent i n v e r y s p e c i a l i z e d g e n e r a . Each b e a r s a v a r i a b l e c o s t a l p r o j e c t i o n on the b a s a l c o s t a l margin which u n d e r l i e s the a n a l a r e a o f t h e f o r e w i n g , c a u s i n g b o t h wings t o move s y n c h r o n o u s l y . The v e n a t i o n i s s i m p l e r , and the Of of the Rs may be a b s e n t . C r o s s v e i n s a r e o f t e n few or a b s e n t . The l e g s a r e weak, and t h e m i d d l e and h i n d l e g s may even be v e s t i g i a l . They c o n s i s t of a s h o r t c o x a , t r o c h a n t e r , and femur, a l o n g e r t i b i a , and u s u a l l y a 5 - j o i n t e d t a r s u s . In t h e m i d d l e and h i n d l e g s t h e f i r s t one or two t a r s a l j o i n t s may be f u s e d t o the t i b i a . The f o r e l e g s a r e l o n g e r and e x t e n d f o r w a r d , t h o s e o f the male b e i n g l o n g e r t h a n t h o s e o f t h e f e m a l e , w i t h a r e v e r s i b l e j o i n t a t the t a r s a l base. The male f o r e t a r s u s i s u s u a l l y l o n g e r than the t i b i a . The p a i r e d t a r s a l c l a w s may be s i m i l a r o r d i s s i m i l a r . In the. l a t t e r case one o f each p a i r may be hooked and p o i n t e d , and the o t h e r l o b e l i k e and b l u n t . The l e g s are u s u a l l y bare o f v e s t i t u r e , and c o l o u r d i f f e r e n c e s o f the segments a r e sometimes u s e f u l taxonomic c r i t e r i a . Even more v a l u a b l e f o r t h i s purpose a re t h e p r o p o r t i o n s o f the l e g segments, p a r t i c u l a r l y o f t h e t a r s a l j o i n t s ' , which a re e x a c t and c o n s t a n t f o r each s p e c i e s , but d i f f e r between the s e x e s , and among the v a r i o u s s p e c i e s . -9-The abdomen, composed o f t e n segments, has p a i r e d g e n i t a l o p e n i n g s . The male g e n i t a l i a are e x t r e m e l y i m p o r t a n t taxonomic f e a t u r e s . The p o s t e r i o r margin of the 9 t h s t e r n i t e a r t i c u l a t e s w i t h a b r o a d , f r e e l y moveable f o r c e p s base, b e a r i n g from i t s d i s t a l a n g l e s a p a i r of 3 o r 4 - j o i n t e d g r a s p i n g f o r c e p s . The s e g m e n t a t i o n o f the f o r c e p s i s o f t e n i n c o m p l e t e and the second j o i n t i s the l o n g e s t and may bear a t u b e r c l e on i t s i n n e r m a r g i n . T h e f o r c e p s and f o r c e p s base v a r y i n shape. The p a i r e d penes, above and a r i s i n g from, the f o r c e p s base, a r e t u b u l a r e x t e n s i o n s of the sperm d u c t s . They may bear c h i t i n o u s appendages i n the form o f s t o u t , s h a r p , p o s t e r i o r l y d i r e c t e d s p u r s on the b a s a l i n n e r m a r g i n s , f l a t parameres on the o u t e r m a r g i n s , o r , as i n most of t h e L e p t o p h l e b i i n a e , l a r g e r e f l e x e d v e n t r a l s p u r s on the a p i c e s . There may a l s o be l e s s e r t e e t h , s p i n e s , and s p i n u l e s . The 9 t h s t e r n i t e o f t h e female i s e xtended back as a n o t c h e d or l o b e d s u b a n a l p l a t e . The p a i r e d o v i d u c t s , o p e n i n g between the 7 t h and 8 t h s t e r n i t e s , are c o v e r e d by the 7 t h s t e r n i t e which i s p r o d uced backwards t o form the egg v a l v e . The t a i l s are two or t h r e e i n number and v a r y i n l e n g t h . S e x u a l dimorphism may be e x h i b i t e d , i n t h a t the m i d d l e t a i l ( c a u d a l f i l a m e n t ) o f the male may be a b s e n t . The a bdominal t e r g i t e s may bear l a t e r a l e x t e n s i o n s e n d i n g i n p o s t e r o - l a t e r a l s p i n e s . The t e r g i t e s o f the t h o r a x and the abdomen v a r y i n c o l o u r and p a t t e r n among gr o u p s , but a r e c o n s t a n t f o r s p e c i e s . The a b d o m i n a l s t e r n i t e s may e x h i b i t g a n g l i o n i c m a r k i n g s . -18-The nymphs v a r y i n form from the s t r e a m - l i n e d , l a t e r a l l y c ompressed, s l e n d e r , h a i r l e s s free-swimming s p e c i e s t o the s p r a w l i n g , d e p r e s s e d , s e t a c i o u s , mud and s i l t d w e l l e r s . The head, t h o r a x and abdomen may bear s p i n e s , as i n the E p h e m e r e l l a . The head v a r i e s i n shape from h i g h and narrow to t h e f l a t , d e p r e s s e d shape found i n the H e p t a g e n i i n a e . I f a f r o n t a l p r o c e s s i s p r e s e n t i t v a r i e s i n shape. The antennae are l o n g e r than t h o s e o f the a d u l t , and are f i l i f o r m . The compound eyes are l a t e r a l i n p o s i t i o n i n the b u r r o w e r s and f r e e swimming g r o u p s , but d o r s a l i n the f l a t t e n e d s p e c i e s . The t h r e e o c e l l i a r e d i r e c t e d f o r w a r d i n the f r e e swimmers, and d o r s a l l y i n the s p r a w l e r s . The mouthparts of the nymphs a r e t y p i c a l of chewing i n s e c t s , w i t h a few m o d i f i c a t i o n s . The s i m p l e , q u a d r a t e labrum may bear s p i n e s , and may be n o t c h e d , e m a r g i n a t e , or b e a r i n g a f r i n g e o f h a i r s on i t s a n t e r i o r m a r g i n . The a s s y m e t r i c a l m a n d i b l e s each bear two t o o t h e d c a n i n e s a p i c a l l y and a g r i n d i n g molar s u r f a c e . Between t h e s e i s a s m a l l p r o s t h e c a . A r i s i n g from'the o u t e r s u r f a c e o f each mandible i n the Ephemeridae i s a l o n g , upward c u r v e d , b l a d e -l i k e t u s k . The o u t e r c a n i n e s i n the P a r a l e p t o p h l e b i a are extended as l o n g , b l u n t t u s k s d i r e c t e d o b l i q u e l y upward. The c a r d o and s t i p e s of each m a x i l l a are d i s c r e e t a r e a s , but t h e g a l e a and l a c i n i a . a r e f u s e d . The m a x i l l a e may bear t e e t h , b r i s t l e s , or a "diatom r a k e " on the crown ( A m e l e t u s ) . The p a l p i a r e u s u a l l y 3 - j o i n t e d . The l a b i u m i s of the u s u a l form, w i t h l o n g , w e l l s e p a r a t e d g l o s s a e and p a r a g l o s s a e . The l a b i a l p a l p i are o r d i n a r i l y 2 or 3 - j o i n t e d . The l e g s o f t h e nymph are s h o r t e r t h a n t h o s e o f the a d u l t . The femora may be f l a t t e n e d i n the s p r a w l i n g f o r m s , and may bear s p i n e s o r h a i r s . The t a r s i a r e 1 - j o i n t e d and bear s i n g l e c l a w s which may be d e n t i c u l a t e and which vary i n form. The l a m e l l a t e , f i l a m e n t o u s , o r plumose g i l l s a r i s e l a t e r a l l y from a l l o r some of the f i r s t seven abdominal segments, and some s p e c i e s a l s o bear plumose g i l l s a t the bases of the coxae, and t h e m a x i l l a e . The g i l l s may be doub l e or s i n g l e and are d i r e c t e d l a t e r a l l y , d o r s a l l y , o r v e n t r a l l y , and sometimes o v e r l a p each o t h e r to form- a s t r o n g s u c k e r d i s c . The g i l l s o f some groups a r e h e a v i l y c h i t i n i z e d on the a n t e r i o r m a r g i n s , or f r i n g e d w i t h h a i r s on the p o s t e r i o r m a r g i n s , as i n the genus C a e n i s . In o t h e r g r o u p s , n o t a b l y the C a e n i s . T r i c o r y t h o d e s , and some E p h e m e r e l l a , the f i r s t p a i r o f g i l l s a r e o p e r c u l a t e . T r a c h e a t i o n o f the g i l l s , i f c o n s p i c u o u s , i s s i m p l e , p a l m a t e , or p e c t i n a t e . The t a i l s are two or t h r e e i n number. The f r e e swimming groups found i n s t i l l w a t e r , s u c h as the S i p h l o n u r u s , B l a s t u r u s , and C a l l i b a e t i s , and - a l s o the Ameletus i n streams bear a heavy f r i n g e of h a i r s on the i n n e r s u r f a c e o f each l a t e r a l t a i l , and on both s i d e s o f the m i d d l e t a i l . The b u r r o w e r s and s p r a w l e r s have bare t a i l s , perhaps w i t h w h o r l s o f a few h a i r s at the j o i n i n g s of the t a i l segments. The t a i l s may be u n i c o l o u r o u s o r banded. The c o l o u r and p a t t e r n of the t e r g i t e s and l e g s . v a r i e s g r e a t l y among groups, but i s c o n s t a n t f o r each s p e c i e s . -12-CHECKLI5T OF THE EMPHEMEROPTERA OF BRITISH COLUMBIA Order Ephemeroptera S u p e r f a m i l y H e p t a g e n i o i d e a F a m i l y S i p h l o n u r i d a e S u b f a m i l y : S i p h l o n u r i n a e Ameletus c e l e r McDunnough Ameletus c e l e r o i d e s McDunnough Ameletus c o n n e c t i n a fYlcDunnough Ameletus c o o k i McDunnough Ameletus monta Mayo Ameletus o r e q o n e n s i s McDunnough Ameletus q u e r u l u s McDunnough Ameletus s i m i l i o r McDunnough Ameletus s p a r s a t u s McDunnough Ameletus s u f f u s u s McDunnough Ameletus t u b e r c u l a t u s McDunnough Ameletus v a l i d u s McDunnough A m e l e t i s v a n c o u v e r e n s i s McDunnough Ameletus v e r n a l i s McDunnough Ameletus s p . 1 * * U n t i l f u r t h e r i n v e s t i g a t i o n o f u n i d e n t i f i e d specimens can be u n d e r t a k e n , they have been numbered, r a t h e r than named by the a u t h o r . -13-P a r a m e l e t u s c o l u m b i a e lYlcDunnough S i p h l o n u r u s a u t u m n a l i s fflcDunnough S i p h l o n u r u s columbianus lYlcDunnough S i p h l o n u r u s o c c i d e n t a l i s Eaton S i p h l o n u r u s s p . 1 S i p h l o n u r u s sp. 2 S i p h l o n u r u s sp. 3 S i p h l o n u r u s sp. 4 S i p h l o n u r u s sp. 5 S i p h l o n u r u s s p . 6 S i p h l o n u r u s s p . 7 S i p h l o n u r u s sp. 8 S i p h l o n u r u s sp. 9 F a m i l y H e p t a g e n i i d a e S u b f a m i l y H e p t a g e n i i n a e Cinyqma i n t e g r u m Eaton Cinyqmula q a r t r e l l i lYIcDunnough Cinyqmula k o o t e n a i ItlcDunnough Cinyqmula mimus ( E a t o n ) Cinyqmula par ( E a t o n ) Cinyqmula r a m a l e y i (Dodds) Cinyqmula u n i f o r m i s (fflcDunnough) Cinyqmula sp. 1 .. .. -14-Epeorus d e c e p t i v u s (McDunnough) Epeorus d u l c i a n a McDunnough Epeorus f l a v / i p e n n i s T r a v e r Epeorus q r a n d i s (McDunnough) Epeorus lonqimanus Eaton Epeorus permaqnus T r a v e r Epeorus s p. 1  Epeorus sp. 2  Epeorus sp. 3 Epeorus sp. 4  Epeorus sp. 5 H e p t a q e n i a e l e q a n t u l a ( E a t o n ) H e p t a q e n i a s i m p l i c o i d e s McDunnough H e p t a q e n i a s o l i t a r i a McDunnough H e p t a q e n i a sp. 1  H e p t a q e n i a s p. 2  H e p t a q e n i a sp. 3  H e p t a q e n i a sp. 4  H e p t a q e n i a s p. 5  H e p t a q e n i a sp. 6  H e p t a q e n i a sp. 7  H e p t a q e n i a sp. 8 R i t h r o q e n a d o d d s i McDunnough R i t h r o q e n a .je.juna Eaton R i t h r o q e n a m o r r i s o n i Banks R i t h r o q e n a r o b u s t a Dodds -15-R i t h r o q e n a v i r i l i s WcDunnough R i t h r o q e n a s p. 1  R i t h r o q e n a s p. 2  R i t h r o q e n a s p . 3 Stenonema terminatum (U/alsh) F a m i l y Ametropodidae S u b f a m i l y ffletretopodinae fflet r e t o p u s b o r e a l i s Eaton F a m i l y B a e t i d a e S u b f a m i l y B a e t i n a e B a e t i s b i c a u d a t u s Dodds B a e t i s i n s i q n i f i c a n s fflcDunnough B a e t i s i n t e r m e d i u s Dodds B a e t i s .jssmondensis fflcDunnough B a e t i s p a r v u s Dodds B a e t i s p e r s e c u t a (IflcDunnough B a e t i s sp. 1 B a e t i s s p . 2 : B a e t i s sp. 3 B a e t i s sp. 4 B a e t i s sp. 5 B a e t i s sp. 6 B a e t i s s p . 7 C a l l i b a e t i s c a r o l u s T r a v e r C a l l i b a e t i s c o l o r a d e n s i s Banks C a l l i b a e t i s h a g e n i ( E a t o n ) -16-C a l l i b a e t i s s p . 1 C a l l i b a e t i s sp. 2 C a l l i b a e t i s s p . 3 C a l l i b a e t i s s p . 4 C a l l i b a e t i s s p . 5 C a l l i b a e t i s s p . 6 C a l l i b a e t i s s p . 7 C a l l i b a e t i s s p . 8 C e n t r o p t i l u r n album 1 C e n t r o p t i l u m b e l l u m C e n t r o p t i l u m b i f u r c a t u m McDunnough C e n t r o p t i l u m conturbatum McDunnough C e n t r o p t i l u m s p . 1  C e n t r o p t i l u m sp. 2  C e n t r o p t i l u m s p . 3  C e n t r o p t i l u m s p . 4 • Meocloeon : sp. 1 S u p e r f a m i l y L e p t o p h l e b i o i d e a F a m i l y L e p t o p h l e b i i d a e S u b f a m i l y L e p t o p h l e b i i n a e L e p t o p h l e b i a s p . 1  L e p t o p h l e b i a s p . 2 B l a s t u r u s c u p i d u s (Day) B l a s t u r u s q r a v a s t e l l a ( E a t o n ) -17-B l a s t u r u s n s b u l o s u s (UJalker) B l a s t u r u s sp• 1 P a r a l e p t o p h l e b i a b i c o r n u t a (fflcDunnough) P a r a l e p t o p h l e b i a d e b i l l s (UJalker) P a r a l e p t o p h l e b i a q r e q a l i s ( E a t o n ) P a r a l e p t o p h l e b i a h e t e r o n e a (fflcDunnough) P a r a l e p t o p h l e b i a p a l l i p e s (Hagen) P a r a l e p t o p h l e b i a r u f iv/enosa .(Eaton) P a r a l e p t o p h l e b i a t e m p o r a l i s (fflcDunnough) P a r a l e p t o p h l e b i a v a c i v a ( E a t o n ) P a r a l e p t o p h l e b i a s p. 1  P a r a l e p t o p h l e b i a sp'. 2  P a r a l e p t o p h l e b i a sp.•3 - P a r a l e p t o p h l e b i a s p. 4  P a r a l e p t o p h l e b i a sp. 5 F a m i l y E p h e m e r e l l i d a e S u b f a m i l y E p h e m e r e l l i n a e E p h e m e r e l l a c o l o r a d e n s i s Dodds E p h e m e r e l l a d o d d s i Weedham E p h e m e r e l l a f l a v / i l i n e a fflcDunnough E p h e m e r e l l a q r a n d i s i n q e n s fflcDunnough E p h e m e r e l l a hecuba hecuba Eaton E p h e m e r e l l a h e t e r o c a u d a t a fflcDunnough -18-E p h e m e r e l l a h y s t r i x T r a v e r E p h e m e r e l l a i n e r m i s Eaton E p h e m e r e l l a i n f r e q u e n s McDunnough E p h e m e r e l l a j a c o b i McDunnough E p h e m e r e l l a l o d i Mayo E p h e m e r e l l a s p i n i f e r a Needham E p h e m e r e l l a t e r e s a T r a v e r E p h e m e r e l l a t i b i a l i s McDunnough  E p h e m e r e l l a sp. 1 F a m i l y T r i c o r y t h i d a e S u b f a m i l y L e p t o h y p h i n a e T r i c o r y t h o d e s minutus T r a v e r T r i c o r y t h o d e s s p . 1 S u p e r f a m i l y Caenoidea F a m i l y Caenidae S u b f a m i l y Caeninae C a e n i s sp. 1 C a e n i s s p . 2 C a e n i s s p . 3 C a e n i s s p . 4 S u p e r f a m i l y Ephemeroidea F a m i l y Ephemeridae S u b f a m i l y Ephemerinae Ephemera s i m u l a n s UJalker -19-Hexaqenia l i m b a t a ( G u e r i n ) P e n t a q e n i a sp. 1 -20-O R D E R E P H E M E R O P T E R A KEY TO ADULTS 1. V e i n s M and C u l s t r o n g l y d i v e r g e n t a t base, w i t h IYI2 s t r o n g l y bent toward the Cu b a s a l l y S u p e r f a m i l y Ephemeroidea V e i n s M and C u l l i t t l e d i v e r g e n t a t base and the f o r k o f M more n e a r l y s y m m e t r i c a l 2. 2. T a i l s two. H i n d t a r s i 4 o r 5 - j o i n t e d . S u p e r f a m i l y H e p t a q e n i o i d e a T a i l s t h r e e . H i n d t a r s i 4 - j o i n t e d 3. 3. F o r c e p s 1 - j o i n t e d . P rosternum 2 or 3 tim e s l o n g e r than b r o a d , so t h a t the coxae a r e ver y c l o s e t o g e t h e r S u p e r f a m i l y Caenoidea F o r c e p s 3 or 4 - j o i n t e d . P rosternum not as above . S u p e r f a m i l y L e p t o p h l e b i o i d e a KEY TO NYMPHS 1. M a n d i b l e s each w i t h an e x t e r n a l t u s k p r o j e c t i n g f o r w a r d and v i s i b l e d o r s a l l y . Head w i t h a c o n s p i c u o u s f r o n t a l p r o c e s s between the bases o f t h e a n t e n n a e . . S u p e r f a m i l y Ephemeroidea M a n d i b l e s with'no e x t e r n a l t u s k s , o r i f p r e s e n t , d e p r e s s e d , and head w i t h no f r o n t a l p r o c e s s between the bases o f t h e antennae . 2. 2. Outer t a i l s f r i n g e d on the i n n e r s i d e o n l y , perhaps w i t h a few s h o r t h a i r s on the o u t e r s i d e . T a i l s may not be f r i n g e d , but may bear w h o r l s of s p i n e s a t each t a i l j o i n i n g . I f t h i s i s s o , the head i s s t r o n g l y d e p r e s s e d , w i t h eyes and antennae d o r s a l . T a i l s may be two . S u p e r f a m i l y H e p t a q e n i o i d e a -21-Outer t a i l f r i n g e d on both s i d e s , o r i f not f r i n g e d , t a i l s u i i t h w h o r l s of s p i n e s a t each j o i n i n g . In the l a t t e r c a s e , the g i l l s o f the second abdominal segment are e l y t r o i d . . . . 3 . G i l l s o f the second abdominal segment e l y t r o i d , q u a d r a t e , and the g i l l s on segments 3-6 have d e e p l y f r i n g e d m a r g i n s . A l l g i l l s s i n g l e S u p e r f a m i l y Caenoidea G i l l s not e l y t r o i d , o r i f g i l l s o f second abdominal segment are e l y t r o i d , t h e y are t r i a n g u l a r ; the margins of the g i l l s on segments 3-6 are not f r i n g e d , and a l l g i l l s a r e d o u b l e . . . S u p e r f a m i l y L e p t o p h l e b i o i d e a SUPERFAIMLY HEPTAGENIOIDEA  Key to A d u l t s H i n d t a r s i 5 - j o i n t e d . Eyes of male not t u r b i n a t e . Outer f o r k o f Rs of h i n d wing p r e s e n t or a b s e n t . Wore than 2 c u b i t a l i n t s r c a l a r i e s i n f o r e w i n g 2. Hind t a r s i 4 - j o i n t e d . Eyes o f male t u r b i n a t e . Outer f o r k o f Rs of h i n d wing a b s e n t . Four l o n g c u b i t a l i n t e r c a l a r i e s i n f o r e w i n g . Hind wing may be absent . F a m i l y B a e t i d a e , S u b f a m i l y B a e t i n a e C u b i t a l i n t e r c a l a r i e s i n 2 p a r a l l e l p a i r s , l o n g and s h o r t a l t e r n a t i n g . Eyes of male s i m p l e . Outer f o r k of Rs i n h i n d wing p r e s e n t or a b s e n t . . . F a m i l y H e p t a q e n i i d a e , S u b f a m i l y H e p t a q e n i i n a e C u b i t a l i n t e r c a l a r i e s of f o r e w i n g not as above. Eyes of male e n t i r e , h o r i z o n t a l l i n e on s u r f a c e m a r k i n g o u t 2 a r e a s . Outer f o r k o f Rs i n h i n d wing p r e s e n t . -..3. -22-3. C u b i t a l i n t e r c a l a r i e s of f o r e w i n g c o n s i s t of a s e r i e s of f o r k i n g or s i n u a t e v e i n l e t s a t t a c h i n g C u l t o h i n d m a r g i n . . F a m i l y S i p h l o n u r i d a e , S u b f a m i l y S i p h l o n u r i n a e C u b i t a l i n t e r c a l a r i e s of f o r e w i n g 2-4 i n number, f r e e b a s a l l y , not f o r k i n g or. s i n u a t e F a m i l y JAmetropodidae, S u b f a m i l y ffletretopodinae Key To Nymphs . Nymph d e p r e s s e d . Eyes and antennae d o r s a l . G i l l s of a s i n g l e l a m e l l a , u s u a l l y w i t h a f i b r i l l i f o r m t u f t a t or near the base F a m i l y H a p t a q e n i i d a e , S u b f a m i l y H e p t a q e n i i n a e Nymph not d e p r e s s e d . Eyes and/or antennae l a t e r a l , a n t e r o -l a t e r a l , or a n t e r i o r . G i l l l a m e l l a e double o r s i n g l e 2. Claws of f o r e l e g b i f i d . Claws of m i d d l e h i n d l e g s l o n g and s l e n d e r , about as l o n g as t h e s h o r t t i b i a F a m i l y Ametropodidae, S u b f a m i l y lYletretopodinae Claws s i m i l a r , s h a r p - p o i n t e d , much s h o r t e r t h a n t i b i a . Claws o f m i d d l e and h i n d l e g s may be l o n g and s l e n d e r , of f o r e l e g s s h o r t , 3. 3. P o s t e r o - l a t e r a l a n g l e s of the a p i c a l a bdominal segments p r o l o n g e d i n t o t h i n f l a t l a t e r a l s p i n e s - i f weak, antennae l e s s than t w i c e the w i d t h of the head. V a r i a b l e appendage on f o r e coxa F a m i l y S i p h l o n u r i d a e , S u b f a m i l y S i p h l o n u r i n a e P o s t e r o - l a t e r a l a n g l e s of a p i c a l abdominal segments h a r d l y more than a c u t e , not p r o l o n g e d i n t o f l a t t h i n l a t e r a l s p i n e s s o , i f weak, antennae mors t h a n t w i c e the w i d t h o f the head. No appendage ..on f o r e coxa F a m i l y B a e t i d a e , S u b f a m i l y B a e t i n a e 1. 2. -23-SUBFAiTlILY 5IPHL0NURINAE ADULT Fore wing narrowed j u s t beyond the base and widened somewhat a t the a n a l a n g l e , r e l a t i v e l y l o n g f o r i t s w i d t h ; the a n t e r i o r b ranch of the. c u b i t a l v e i n i s a t t a c h e d to the i n n e r margin by a s e r i e s of c r o s s - v e i n s , which a r e o f t e n f o r k e d and s i n u a t e ; the h i n d wing i s a l m o s t o r f u l l y as wide as l o n g , the a n a l r e g i o n w e l l - d e v e l o p e d ; the c o s t a l p r o j e c t i o n i s not e s p e c i a l l y p r o m i n e n t , u s u a l l y somewhat o b t u s e ; the t a r s i are f i v e - j o i n t e d ; the b a s a l j o i n t s o f the m i d d l e and h i n d t a r s i are more o r l e s s c o m p l e t e l y f u s e d w i t h the t i b i a e ; a l l j o i n t s o f ' t h e male f o r e t a r s u s f r e e and movable, the f i r s t j o i n t a t l e a s t l / 3 the l e n g t h of t h e second j o i n t , and may e q u a l o f exceed i t ; t he f o r c e p s . a r e more o r l e s s d i s t i n c t l y f o u r - j o i n t e d ; the f o r c e p s base i s u s u a l l y v e r y l o n g , more or l e s s d e e p l y e m a r g i h a t e i n i t s a p i c a l m a r g i n , between the f o r c e p s l i m b s ; b a s a l j o i n t i s u s u a l l y r i n g - l i k e , o f t e n f u s e d w i t h the second j o i n t , which i s o f t e n s t r o n g l y bowed; two ( o r r a r e l y t h r e e ) t e r m i n a l j o i n t s , t o g e t h e r not l o n g e r than the second. In Ameletus, s u b a n a l p l a t e o f female more o r l e s s d e e p l y c a r v e d out i n the a p i c a l m a r g i n , convex i n o t h e r g e n e r a ; two t a i l s . NYMPH Body s t r e a m - l i n e d , much compressed; head i n f l e x e d ; l e g s l o n g ; c l a w s l o n g and s l e n d e r , , not. d e n t i c u l a t e ; l a t e r a l margins of a p i c a l a bdominal t e r g i t e s expanded i n t o f l a t l a t e r a l e x t e n s i o n s , l e s s so i n Ameletus; a s p i n e on the p o s t e r o - l a t e r a l a n g l e o f each m i d d l e and a p i c a l t e r g i t e ; g i l l s on segments 1-7, s i m p l e and s i n g l e , e x c e p t -24-i n S i p h l o n u r u s where g i l l s a r e double and l a m e l l a t e , p a r t s s i m i l a r ; t h r e e t a i l s , m i d d l e one h e a v i l y f r i n g e d on each s i d e , l a t e r a l ones on i n n e r m a rgins o n l y . SUBFAMILY SIPHLONURINAE  Key To A d u l t s 1. Claws of each t a r s u s d i s s i m i l a r . C o s t a l a n g u l a t i o n of h i n d wing a c u t e . Fork of M d e t a c h e d . Subanal p l a t e concave.. •Ameletus Eaton Claws a l l s h a r p - p o i n t e d . C o s t a l a n g u l a t i o n o f h i n d wing o b t u s e . Fork of M not d e t a c h e d . Subanal p l a t convex 2. 2. H i n d t a r s u s s h o r t e r than or s u b e q u a l to t i b i a . P o s t e r i o r branch of M forms a l m o s t a r i g h t a n g l e a t i t s u n i o n w i t h the stem.. P a r a m e l e t u s Bengtsson H i n d t a r s u s l o n g e r than t i b i a . Fork o f ffl n o r m a l . S i p h l o n u r u s Eaton Key To Nymphs 1. G i l l l a m e l l a e s i n g l e on a l l segments 2. G i l l l a m e l l a e double on segments one and two, and sometimes on o t h e r segments. L a m e l l a e e q u a l i n s i z e . S i p h l o n u r u s Eaton 2. A f r i n g e o f p e c t i n a t e s p i n e s on crown of g a l e a - l a c i n i a . No p i n c e r l i k e p r o c e s s on t i p of l a b i a l p a l p Ameletus Eaton No p e c t i n a t B s p i n e s on crown of g a l e a - l a c i n i a . A p i n c e r - l i k e p r o c e s s hear t i p of l a b i a l p a l p . . . . . , P a r a m e l e t u s Bengtsson -25-GENUS AHOELETUS EATON Ameletus, Needham, 1935, The B i o l o g y of M a y f l i e s , 446, ( B i b l i o g r a p h y ) A d u l t ; Medium s i z e d , b r o w n i s h or y e l l o w brown, abdomen of female o f t e n d a r k e r than t h a t of male; v e r t e x and o c c i p u t o f female u s u a l l y w i t h dark submedian marks; h i n d margin of head s l i g h t l y concave; eyes of male l a r g e ; u s u a l l y c o n t i g u o u s above, not d i v i d e d , a t r a n s -v e r s e band of p a l e r c o l o u r may ext e n d o b l i q u e l y a c r o s s the o u t e r s u r f a c e ; f o r e w i n g t h r e e t i m e s as l o n g as wide; h i n d wing w e l l -d e v e l o p e d , c o s t a l a n g u l a t i o n a c u t e ; median v e i n o f h i n d wing f o r k e d near base; v e n a t i o n dark; ;. humeral c r o s s v e i n s t r o n g and d a r k ; many c r o s s v e i n s i n c o s t a l h a l f o f f o r e w i n g may be brown-margined, so t h a t wing l o o k s s p e c k l e d ; s t i g m a t i c c r o s s v e i n s u s u a l l y f o r k e d and anastamosed; f o r e l e g o f male as l o n g as body; f i r s t f o r e t a r s a l j o i n t l / 3 t o l / 2 as l o n g as second; a l l c l a w s d i s s i m i l a r ; abdominal t e r g i t e s u s u a l l y w i t h wide dark p o s t e r i o r m a r g i n s , p o s t e r o - l a t e r a l a n g l e s , and e x t e n s i o n s a l o n g p l e u r a l f o l d ; s t e r n i t e s o f t e n w i t h b l a c k o r brown g a n g l i o n i c marks; f o r c e p s base w i t h a t u b e r c l e o r p r o j e c t i o n on each s i d e o f a p i c a l e x c a v a t i o n ; two t e r m i n a l j o i n t s , s h o r t e r t o g e t h e r t h a n second j o i n t ; penes l o n g and s l e n d e r , may be w i t h s p i n e s on i n n e r m a r g i n , and t i p s may be seen beyond f o r c e p s p l a t e , when viewed from b e n e a t h . Nymphs; ( T i a x i l l a r y and l a b i a l p a l p s t h r e e - j o i n t e d , f o r m e r s h o r t and weak; m a x i l l a w i t h a broad crown, b e a r i n g l o n g p e c t i n a t e s p i n e s ; m a n d i b l e s t r i a n g u l a r , w i t h c a n i n e s a t one p o i n t and molar s u r f a c e a t a n o t h e r ; -26-labrum a l i t t l e l o n g e r than wide, e m a r g i n a t e on f r o n t a l b o r d e r ; l e g s r a t h e r s h o r t ; p o s t e r o - l a t e r a l s p i n e s u s u a l l y on segments 4-9, but s h o r t and weak on segments 4-6; the l a t e r a l margins on t h e s e o n l y v e r y s l i g h t l y compressed; g i l l s s i n g l e , s i m p l e , s m a l l and o v a l ; t a i l s u s u a l l y w i t h a wide dark t r a n s v e r s e band a t m i d d l e and a narrow one a t apex. Genotype: Ameletus s u b n o t a t u s E a t o n . AfflELETUS  Key To A d u l t s 1. C r o s s v e i n s f a i n t l y or s t r o n g l y marked w i t h brown to b l a c k 2. No m a r g i n a l c r o s s v e i n s . . . . 8. 2. G a n g l i o n i c markings dark 3. No dark g a n g l i o n i c m a r k i n g s . . .7. 3. A n t e r i o r t w o - t h i r d s of abdominal t e r g i t e s h y a l i n e w h i l e p o s t e r i o r o n e - t h i r d deep brown. Wings h y a l i n e 4. Wings c l o u d y or t i n t e d 5. 4. C r o s s v e i n s dark e x c e p t i n c o s t a - b a s a l a r e a . . . . . . . . c o n n e c t i n a iYlcD C r o s s v e i n s i n c o n s p i c u o u s and o n l y f a i n t l y shaded t u b e r c u l a t u s ItlcD 5. Wings not t i n g e d , a l t h o u g h c l o u d s p r e s e n t i n wings. Abdominal t e r g i t e s deep brown s i m i l i o r IflcD Wings t i n g e d . Abdominal t e r g i t e s l i g h t - c o l o u r e d ..6. 6. Wings w i t h r e d d i s h brown t i n g e . Abdominal t e r g i t e 1 dark brown, r e s t s e m i - h y a l i n e .monta fflayo Wings of male a m b e r - t i n g e d . C l o u d s i n w i n g s . Abdominal -27-t e r g i t e s y e l l o w - b r o w n s p a r s a t u s fflcD 7. UJings t i n g e d w i t h umber brown, p a l i n g somewhat o u t w a r d l y . Abdom-i n a l t e r g i t e 1 b l a c k , o t h e r s b r i g h t y e l l o w b o r d e r e d p o s t e r i o r l y w i t h brown . . . s u f f u s u s lYlcD UJings not t i n g e d , a l t h o u g h c l o u d y . Abdominal t e r g i t e s p i n k i s h brown . v a l i d u s fflcD 8. G a n g l i o n i c a r e a s marked w i t h orange to b l a c k ...9. No g a n g l i o n i c m arkings 12. 9. Wings not t i n g e d . . . . 10. LUings f a i n t l y smoksyor grey t i n g e d . Not s p e c k l e d or c l o u d y c e l e r fflcD 10. G a n g l i o n i c m arkings dark brown .....11. G a n g l i o n i c m a r k i n g s orange. c o o k i fflcD 11. Two s m a l l s p i n e s on i n n e r margin of each d i v i s i o n o f penes. Abdominal t e r g i t e s 2 to 7 y e l l o w i s h brown.... . c e l e r o i d e s IflcD S i n g l e l o n g s l e n d e r s p i n e on i n n e r m a r g i n of each d i v i s i o n , o f the penes. Abdominal t e r g i t e s 2 to. 7 g r e y i s h w h i t e . v e r n a l i s lYlcD 12. UJings t i n g e d w i t h brown, umber brown, or amber 13. UJings p a l e h y a l i n e q u e r u l u s BlcD 13. UJings t i n g e d e n t i r e l y or i n p a r t w i t h brown o r umber brown...14. UJings e n t i r e l y t i n g e d w i t h amber , .sp. 1 14. Wings t i n g e d . w i t h brown a t base. Abdominal t e r g i t e s y e l l o w -w h i t e o r e q o n e n s i s fflcD Wings s t r o n g l y and e n t i r e l y t i n g e d w i t h umber brown. Abdominal t e r g i t e s y e l l o w brown v a n c o u v e r e n s i s (Y!cD -28-Key To Nymph 1. Ta i J s p a l e ochreous . c e l e r UllcD T a i l s w i t h one or more dark bands, i n one or more of the t h r e e t a i l s 2. 2. M i d d l e t a i l p a l e r than o u t e r t a i l s , w hich are l i g h t brown. M i d d l e t a i l w i t h a f a i n t brown narrow band i n m i d d l e v a l i d u s McD A l l t h r e e t a i l s s i m i l a r l y marked 3. 3. T a i l s w i t h s i n g l e median, dark band and dark t i p s 4. T a i l s w i t h s i n g l e median dark band, but p a l e b a s a l l y and a p i c a l l y • 6. 4. V e n t r a l l y on f i r s t s even segments t h e r e i s a broad dark broken m e d i o - v e n t r a l band, t a p e r i n g c e p h a l a d on each segment to a p o i n t and not q u i t e a t t a i n i n g a n t e r i o r m a r g i n , but b r o a d e n i n g out i n p o s t e r i o r h a l f of segments, e s p e c i a l l y of segments 5 and 6, where i t a l m o s t c o e l e s c e s w i t h a dark l a t e r a l s t r i p e , e x t e n d i n g down segments s l i g h t l y - i n t e r i o r t o p a l e edges. Segments 8 and 9 brown w i t h s m a l l w h i t e s p o t s on a n t e r i o r margin s u f f u s u s McD U e n t r a l l y p a l e brown w i t h b r o a d l y p a l e l a t e r a l edges, e x c e p t on segment 9 and a s m a l l p a l e dot near a n t e r o - l a t e r a l c o r n e r . 5. 5. G i l l s p a l e w i t h f a i n t t r a c h e a t i o n . An i n t e r i o r dark band j u s t w i t h i n the d o r s a l margin a n d . f a i n t t r a c e s o f c h i t i n o u s t h i c k e n i n g a l o n g v e n t r a l edge v e r n a l i s McD -29-T r a c h e a t i o n more d i s t i n c t but s t i l l not p r o m i n e n t . I n t e r i o r dark band i s c l o s e r t o d o r s a l margin, t h a n p r e v i o u s l y , and t h i c k e n i n g a l o n g v e n t r a l edge i s h e a v i e r c o n n e c t i n a iYlcD 6. No dark i n t e r i o r c h i t i n o u s band on g i l l s 7. A dark i n t e r i o r o r d o r s a l band of c h i t i n on g i l l s 8. 7. T r a c h e a t i o n o f g i l l s s p a r c e , i n d i s t i n c t c e l e r o i d e s M c D T r a c h e a t i o n o f g i l l s ' p l e n t i f u l , d i s t i n c t . s p a r s a t u s IKlcD 8. V e n t r a l l y p a l e brown.with no p a t t e r n o r e q o n e n s i s IYlcD V e n t r a l l y p a l e w i t h v a r i o u s dark p a t t e r n s 9. 9. C h i t i n o u s t h i c k e n i n g a l o n g d o r s a l and v e n t r a l edge o f g i l l s . . . . , . s i m i l i o r fflcD C h i t i n o u s band w i t h i n d o r s a l edge of g i l l s . . . 10. 10. C h i t i n o u s band near d o r s a l edge of g i l l s c o o k i IYlcD C h i t i n o u s band w e l l w i t h i n d o r s a l edge of g i l l s . 11. 11. C h i t i n o u s band o f g i l l s e x t e n d s o n l y 2/3 t o t i p of g i l l . . . q u e r u l u s IYlcD. C h i t i n o u s band of g i l l s as f a r from d o r s a l edge as w i d t h o f base of g i l l monta Mayo Unknown . Ameletus v a n c o u v e r e n s i s IYlcD Ameletus t u b e r c u l a t u s IYlcD AIYIELETUS CELER RlcDUNNOUGH Ameletus c e l e r McDunnough, Needham, 1935, The B i o l o g y of M a y f l i e s , 451 ( B i b l i o g r a p h y ) A d u l t s ; . . . . . . . . Head and t h o r a x b l a c k i s h brown, • abdomen y e l l o w i s h brown; -30-wings d u l l h y a l i n e , f a i n t l y smoky o r g r e y - t i n g e d , not s p e c k l e d or c l o u d y ; l o n g i t u d i n a l v e i n s and c r o s s v e i n s f i n e and brou/n; abdominal t e r g i t e s 2-7 s e m i - h y a l i n e , p a l e y e l l o w i s h - b r o w n ; p o s t e r i o r m a r gins dark brown w i t h narrow brown submedian s t r e a k s e x t e n d i n g f o r w a r d , and not a t t a i n i n g a n t e r i o r m a r g i n ; t e r g i t e s 8-10 opaque, d a r k e r ; s t e r n i t e s p a l e r , g a n g l i o n i c a r e a s marked w i t h b r o w n i s h b l a c k ; t a i l s w h i t i s h and smoky, j o i n i n g s b l a c k i s h brown; penes w i t h s e v e r a l s m a l l s p i n e s on i n n e r margin of each d i v i s i o n . Nymph: T a r s i w i t h deep brown d i s t a l bands o n l y ; no dark l o n g i t u d i n a l s t r i p e s on v e n t e r o f the abdomen; g a n g l i o n i c m a r k i n g s p r e s e n t ; t r a c h e a t i o n o f g i l l s s p a r s e and i n d i s t i n c t , no dark i n t e r i o r c h i t i n o u s band; t a i l s p a l e o c h r e o u s . D i s t r i b u t i o n : B r i t i s h C o l u m b i a , A l b e r t a . No specimens o f t h i s s p e c i e s were examined. AMELETUS CELEROIDES McDUNNOUGH Ameletus c e l e r o i d e s McDunnouqh, Needham, 1935, The B i o l o g y of May-f l i e s , 451 ( B i b l i o g r a p h y ) A d u l t : T h i s s p e c i e s i s s i m i l a r to A_;_ c e l e r , but s m a l l e r and p a l e r ; p o s t e r o - l a t e r a l a r e a of pronotum creamy; wings not smoky; a n t e r i o r p o r t i o n s of t e r g i t e s creamy, e s p e c i a l l y l a t e r a l l y on segments 6-8, and a l s o on s t e r n i t e s 7 and 8, and a p a l e creamy l i n e on l a t e r a l edge of s t e r n i t e 9; g a n g l i o n i c m a r k i n g s dark brown; penes w i t h two -31-s m a l l s p i n e s on i n n e r margin o f each d i v i s i o n ; penes l o b e s b r o a d l y d i v e r g e n t a p i c a l l y ; a l l f o r c e p s j o i n t s s l e n d e r . Nymph: S i m i l a r t o Pu_ c e l e r , but t a r s i dark banded b a s a l l y as w e l l as d i s t a l l y ; t a i l s p a l e a t base and apex, w i t h a broad dark median band. D i s t r i b u t i o n : B r i t i s h C o l u m b i a , A l b e r t a . No specimens o f t h i s s p e c i e s were examined. AMELETUS CONNECTINA McDUNNOUGH Ameletus c o n n e c t i n a McDunnouoh. McDunnough, 1939, Can. E n t . 71:50 ( B i b l i o g r a p h y ) ' A d u l t : Uiings h y a l i n e w i t h v e i n s and f i n e c r o s s v e i n s d a r k , e x c e p t i n c o s t a - b a s a l a r e a ; abdomen d o r s a l l y w i t h the a n t e r i o r 2/3 of t e r g i t e s d u l l ; - d i r t y w h i t i s h , v e i n e d w i t h d a r k e r and w i t h t r a c e s of two broken s u b d o r s a l l i n e s ; t he p o s t e r i o r l / 3 d u l l b l a c k - b r o w n ; s t e r n i t e s w i t h dark g a n g l i o n i c m a r k i n g s . Nymph: Femora p a l s w i t h a l a r g e r e c t a n g u l a r brown p a t c h i n the median a r e a , w i t h s m a l l brown a r e a s a t base and apex, and w i t h a brown s t r e a k e x t e n d i n g back from apex a l o n g the d o r s a l edge; t i b i a e s l i g h t l y t i n g e d w i t h brown a t base. No d i s t i n c t m a c u l a t i o n on s t e r n i t e s , e x c e p t a p a l e l a t e r a l edge and a n t e r i o r w h i t e d o t s on each s t e r n i t e . G i l l s w i t h an i n t e r i o r dark band c l o s e t o d o r s a l margin and a t h i c k -ened v e n t r a l m a r g i n . T r a c h e a t i o n d i s t i n c t but not p r o m i n e n t . T a i l s p a l e , w h i t i s h , v e r y b r o a d l y banded w i t h brown i n m i d d l e and a p i c a l l y . D i s t r i b u t i o n : B r i t i s h C olumbia -32-No specimens o f t h i s s p e c i e s were examined. AMELETUS COOK I McDUNNOUGH Ameletus C o o k i McDunnough, Needham, 1935, The B i o l o g y o f M a y f l i e s , 452 ( B i b l i o g r a p h y ) A d u l t : S m a l l dark s p e c i e s , w i t h orange-brown abdominal t e r g i t e s ; t h o r a x b l a c k i s h - b r o w n , w i t h orange s h a d i n g on and b e f o r e mesothor* a c i c s c u t e l l u m , a t wing and l e g bases; wings h y a l i n e , l o n g i t u d i n a l v e i n s amber; abdominal t e r g i t e s orange-brown, w i t h s u f f u s e d brown s h a d i n g a l o n g l a t e r a l m a r g i n s , f o r m i n g o b s c u r e s e m i - t r i a n g u l a r p a t c h e s i n the p o s t e r o - l a t e r a l c o r n e r s , sometimes e x t e n d i n g narrow a l o n g the p o s t e r i o r m a r g i n . S t e r n i t e s 2-6 d u l l h y a l i n e w h i t i s h , 7 and 8 opaque, b r i g h t y e l l o w i s h , 9 b l a c k i s h brown shaded w i t h o range; g a n g l i o n i c m a r k i n g s orange; penes each b e a r i n g a s p i n e on i n n e r margin near m i d d l e ; penes c u r v e d a t t i p ; t a i l s d i r t y w h i t i s h j o i n i n g s d a r k . Nymph: Femur w i t h a brown c e n t r a l p a t c h on o u t e r s i d e , which may be red u c e d ; t i b i a e brown a t base; s t e r n i t e s p a l e , s t e r n i t e s 3-7 each w i t h a p a i r of s m a l l brown submedian s p o t s near a n t e r i o r margin and a l a t e r a l brown s t r e a k , which i s f a i n t on segments 6 and 7; s t e r n i t e s 8 and 9 a r e each c r o s s e d by a broad c u r v e d brown band, l e a v i n g o n l y the a n t e r o - l a t e r a l and p o s t e r o - m e d i a l a r e a s p a l e ; g i l l s each w i t h a t h i n b l a c k c h i t i n o u s band near d o r s a l m a r g i n ; t a i l s p a l e w i t h a broad deep brown median band. D i s t r i b u t i o n : Montana, B r i t i s h C o l u m b i a . No specimens o f t h i s s p e c i e s were examined. -33-AfflELETUS filONTA MAYO  Ameletus monta Mayo, Hflayo, 1952, Pan.Pac.Ent.,' 28:93 ( b i b l i o g r a p h y ) A d u l t : ( M a l e ) UJings w i t h a r e d d i s h - b r o w n t i n g e due t o prominence o f re d d i s h - b r o w n l o n g i t u d i n a l v e i n s ; c r o s s v e i n s l e s s d i s t i n c t ; s t i g m a t i c a r e a m i l k y ; f i r s t abdominal t e r g i t e dark brown, t e r g i t e s 2-7 s e m i - h y a l i n e , washed w i t h p a l e t r a c h e a t i o n s and very p a l e l a t e r a l l y , t e r g i t e s 8-10 dark brown w i t h a p a l e s t r e a k on the edges; s t e r n i t e s 2-8 w i t h b l a c k i s h g a n g l i o n i c m a r k i n g s ; penes narrow, p a r a l l e l , s l i g h t l y i n c u r v e d a t t i p s , each w i t h 3 prominent s p i n e s a t base; t a i l s w h i t e w i t h minute brown h a i r s , each segment d e l i c a t e l y b o r d e r e d p o s t e r i o r l y w i t h r e d d i s h h a i r . Nymph: Legs y e l l o w i s h brown, w i t h l a s t t a r s a l segment dark r e d d i s h brown; abdominal s t e r n i t e 1 p a l e , 2-4 and 8 u n i f o r m l y p a l e , 5-7 p a l e e x c e p t around g a n g l i o n i c m a r k i n g s ; 9 p a l e ; each s t e r n i t e w i t h brown p a t c h e s on e i t h e r s i d e o f m i d l i n e , and s m a l l d i s t i n c t w h i t e p a t c h e s on a n t e r o - l a t e r a l c o r n e r s ; t r a c h e a e o f g i l l s numerous; s c l e r o t i z e d band on g i l l s as f a r from d o r s a l margin as w i d t h o f base; t a i l s f r i n g e d , p a l e w i t h dark brown median band. D i s t r i b u t i o n : B r i t i s h Columbia No specimens of t h i s s p e c i e s were examined. AMELETUS OREGQNENSIS McDUNNOUGH Ameletus o r e q o n e n s i s fflcDunnough, McDunnough, 1936, Can.Ent., 68:208 ( B i b l i o g r a p h y ) -34-A d u l t : Head and t h o r a x b l a c k i s h , abdomen y e l l o w i s h w h i t e ; wings h y a l i n e , c o s t a l a r e a f a i n t l y a m b e r - t i n g e d a t base; b a s a l a n a l a r e a 1 and s t i g m a t i c r e g i o n of f o r e w i n g s u f f u s e d w i t h s e p i a brown; the b a s a l a r e a o f the h i n d w i n g , e x t e n d i n g a l o n g c o s t a h a l f way t o apex, i s p r e d o m i n a n t l y brown; \/enation brown; c r o s s v e i n s numerous, anastomosed i n stigma;;;,-" a b d o m i n a l t e r g i t e s 2 smoky brown, 3-6 s e m i -h y a l i n e , p a l e y e l l o w i s h w h i t e w i t h p o s t e r i o r m a r g i n s , t r i a n g l e s i n the p o s t e r o - l a t e r a l c o r n e r s , and two narrow s u b m e d i a h s t r e a k s dark brown, 7-9 opaque, m a r k i n g s the same but b l a c k i s h brown, 10 brown w i t h p a l e p o s t e r i o r m a r g i n ; s t e r n i t e s 1-6 s e m i - h y a l i n e , p a l e y e l l o w i s h w h i t e , 7-9 opaque, s u f f u s e d w i t h brown; no g a n g l i o n i c m a r k i n g s ; penes u n i q u e , each composed of a wide c h i t i n o u s p i e c e b e a r i n g t h r e e b road s p i n e s a t i t s apex; penes s h o r t , not r e a c h i n g the apex of t h e f o r c e p s base; t a i l s p a l e smoky, not darkened a t j o i n i n g s . Nymph: B a s a l a r e a o f femur p a l e w i t h a deep broad brown median band; a p i c a l s e c t i o n more or l e s s l i g h t e r brown, e s p e c i a l l y i n the f o r e femur; b a s a l h a l v e s of t i b i a e p a l e , a p i c a l h a l v e s brown; abdominal s t e r n i t e s u n i f o r m l y p a l e brown, w i t h no g a n g l i o n i c m a r k i n g s ; g i l l s p a l e , w i t h poor t r a c h e a t i o n ; a dark brown i n t e r i o r band of c h i t i n i n the g i l l s and w i t h v e n t r a l margins b r o a d l y but i n d i s t i n c t l y t h i c k e n e d w i t h c h i t i n ; t a i l s brown a t base and then banded a l t e r n a t e l y p a l e and dark brown, t i p s w h i t i s h . -35-D i s t r i b u t i o n : Oregon, B r i t i s h C o l u m b i a . No specimens o f t h i s s p e c i e s were examined. AIY1ELETUS QUERULU5 McDUNNOUGH Ameletus q u e r u l u s fflcDunnough, fflcDunnough, 1938, Can. E n t . , 70:29 ( B i b l i o g r a p h y ) A d u l t : ( f f l a l e ) UJings p a l e h y a l i n e w i t h l o n g i t u d i n a l v e i n s and c r o s s v e i n s i n p t e r o s t i g m a t i c a r e a brown; abdominal t e r g i t e s 2-6 s e m i - h y a l i n e , l i g h t y e l l o w - b r o w n s h a d i n g i n t o deeper brown a l o n g t h e p o s t e r i o r b o r d e r s , and r a t h e r s t r o n g l y marked w i t h a f i n e dark t r a c h a a t i o n a r i s i n g from the dark l a t e r a l band, t e r g i t e s 7-10 opaque, s l i g h t l y deeper i n c o l o u r t h a n a n t e r i o r t e r g i t e s and w i t h some l a t e r a l d a r k e r s h a d i n g ; s t e r n i t e s w h i t i s h , s u f f u s e d w i t h d u l l smoky; no g a n g l i o n i c m a r k i n g s . Nymph: Femora p a l e , t i p p e d w i t h dark and each w i t h s m a l l median o v a l dark s p o t ; abdominal s t e r n i t e s 1-7 p a l e , 8-9 d a r k ; s t e r n i t e s 1 and 2 each bear 2 dark submedian s p o t s , much l a r g e r on 2; on s t e r n i t e s 3-6 t h e s e s p o t s become p r o g r e s s i v e l y l a r g e r , u n i t i n g w i t h dark s h a d i n g on the a n t e r i o r margins to form l a r g e i r r e g u l a r l y t r i a n g u l a r p a t c h e s , o c c u p y i n g the whole median a r e a , a p i c e s t o u c h i n g the p o s t e r i o r m a r g i n s ; f a i n t l a t e r a l dark p a t c h e s on s t e r n i t e s 3-4 a l s o become p r o g r e s s i v e l y l a r g e r and on 5 c o n n e c t w i t h the dark median a r e a ; no l a t e r a l p a t c h e s on s t e r n i t e 6 ; on s t e r n i t e 7 the t r i a n g u l a r a r e a i s r e v e r s e d ; g i l l s o v a l w i t h the dark c h i t i n o u s band w e l l w i t h i n the d o r s a l margin and e x t e n d i n g o n l y 2/3 t o the t i p of t h e g i l l ; 36-t a i l s p a l e w i t h a m o d e r a t e l y uiide dark median band. D i s t r i b u t i o n : B r i t i s h C olumbia No specimens of t h i s s p e c i e s were examined. AMELETUS SIMILIQR McDUNNOUGH Ameletus s i m i l i o r McDunnough, Needham, 1935, The B i o l o g y o f May-f l i e s , 456 ( B i b l i o g r a p h y ) A d u l t : Medium s i z e d dark s p e c i e s ; head and t h o r a x s h i n y b l a c k i s h brown i n male; t h o r a x b r i g h t r e d d i s h brown i n f e m a l e ; wings h y a l i n e , c l o u d s of l i g h t umber brown i n male; v e n a t i o n d a r k , s e v e r a l c r o s s -v e i n s of f o r e w i n g margined w i t h brown, so wing appears s p e c k l e d ; a b dominal t e r g i t e s deep brown w i t h l i g h t e r s h a d i n g on p o s t e r i o r m a r g i n s ; s t e r n i t e s w i t h b l a c k , h e a r t - s h a p e d g a n g l i o n i c m a r k i n g s ; t u b e r c l e s on f o r c e p s base p o o r l y d e v e l o p e d ; penes s l i g h t l y i n c u r v e d a t t i p s , each bears one o r more s p i n e s on i n n e r m a r g i n ; s u b a n a l p l a t e o f female s m a l l , c o v e r i n g l e s s t h a n one h a l f the t e n t h segment. Nymph: Femora each w i t h a p a l e s t r e a k e x t e n d i n g backward from d i s t a l e x t r e m i t y ; t a r s i w i t h dark brown a p i c a l bands; s t e r n i t e s 3, 4, and 8 dark brown, o t h e r s p a l e w i t h f a i n t dark l a t e r a l dashes and o b s c u r e submedian s t r e a k s u n i t i n g a t t i m e s , e s p e c i a l l y on s t e r n i t e 8, t o form p a t c h e s ; s t e r n i t e 9 e n t i r e l y p a l e w i t h a minute dark dot i n each a n t e r o - l a t e r a l c o r n e r ; g a n g l i o n i c markings d i s t i n c t and b l a c k i s h ; g i l l s n a r r o w l y o v a l , f e e b l y t r a c h e a t e d , and w i t h a c h i t i n o u s t h i c k -e n i n g a l o n g t h e d o r s a l . a n d v e n t r a l edges; t a i l s p a l e , w i t h a b r o a d deep brown median band. -37-D i s t r i b u t i o n : A l b e r t a , B r i t i s h C olumbia No specimens o f t h i s s p e c i e s mere examined. AMELETUS SPARSATU5 lYIcDUNNOUGH Ameletus s p a r s a t u s McDunnough, Needham, 1935, The B i o l o g y o f May-f l i e s , 456 ( B i b l i o g r a p h y ) A d u l t : Head, pronotum and metanotum b l a c k , a n t e r i o r p a r t of l a t t e r shaded w i t h brown; mesonotum r e d d i s h brown a n t e r i o r l y , y e l l o w i s h brown m e d i a l l y and b l a c k i s h brown l a t e r a l l y ; s c u t e l l u m y e l l o w i s h brown w i t h b l a c k l a t e r a l m a r g i n s ; wings h y a l i n e , a m b e r - t i n t e d i n male; v e n a t i o n brown; c r o s s v e i n s i n c o s t a l h a l f o f f o r e w i n g basad o f the b u l l a margined w i t h brown, so t h a t wing appears s p e c k l e d ; c r o s s v e i n s i n s t i g m a t i c a r e a s t r o n g l y anastomosed; abdominal t e r g i t e s 2-6 y e l l o w i s h brown, r e s t g o l d e n brown; a l l t e r g i t e s b r o a d l y shaded w i t h d a r k e r brown on l a t e r a l and p o s t e r i o r m a r g i n s ; s t e r n i t e s 2-6 d u l l smoky brown, r e s t opaque y e l l o w i s h brown, w i t h dark a n t e r o -median p a t c h e s on.7 and 8, and a b r o a d deep brown l a t e r a l edging on 9; penss as i n A^ c o o k i . Nymph: Legs banded; abdominal t e r g i t e s 1, 7 and 10 p a l e w i t h a dark a n t e r i o r m a r g i n ; t e r g i t e 9 and s t e r n i t e s 8 and 9 dark r e d d i s h t o orange brown; o t h e r t e r g i t e s w i t h p a l e l a r g e o v a l l a t e r a l s p o t s , p a l e median a r e a s bounded by dark brown submedian o b l i q u e s t r e a k s , a n t e r i o r and p o s t e r i o r margins v e r y n a r r o w l y b l a c k , e s p e c i a l l y i n -38-p o s t e r o - l a t e r a l c o r n e r s ; s t e r n i t e s s i m i l a r , w i t h o u t p a l e median s t r e a k ; t a i l s p a l e , w i t h wide median b l a c k band and narrow a p i c a l b l a c k band; no c h i t i n o u s band i n g i l l s ; t r a c h e a t i o n of g i l l s p l e n t i f u l and d i s t i n c t . D i s t r i b u t i o n : B r i t i s h C olumbia No specimens o f t h i s s p e c i e s were examined. AfflELETUS SUFFUSUS fflcDUNNOUGH Ameletus s u f f u s u s McDunnough, rflcDunnough, 1936, Can.Ent., 68:210 ( B i b l i o g r a p h y ) A d u l t : (IKlale) UJings t i n g e d w i t h umber-brown, p a l i n g somewhat o u t w a r d l y ; l o n g i t u d i n a l v e i n s b r i g h t brown, c r o s s v e i n s smoky brown, tho s e b e f o r e the b u l l a numerous and t h o s e i n the p t e r o s t i g m a t i c a r e a e v e n l y anastomosed; abdominal t e r g i t e 1 b l a c k i s h , o t h e r s r a t h e r b r i g h t y e l l o w , b r o a d l y b o r d e r e d w i t h brown p o s t e r i o r l y and s l i g h t l y brown-shaded a l o n g l a t e r a l edges where t r a c h e a t i o n shows as a f i n e dark network; t e r g i t e s 8-10 are opaque w i t h a more extended brown s u f f u s i o n ; s t e r n i t e s d u l l p a l e o c h r e o u s ; s t e r n i t e 9 and f o r c e p s p l a t e t i n g e d w i t h y e l l o w c e n t r a l l y ; no g a n g l i o n i c m a r k i n g s ; penes l o b e s wide a p a r t w i t h a p i c e s d i r e c t e d o u t w a r d l y ; t a i l s smoky, f a i n t l y dark r i n g e d . Nymph: Legs p a l e w i t h a dark c e n t r a l p a t c h on each femur; t a r s i banded b a s a l l y and a p i c a l l y w i t h brown; f i r s t 7 abdominal s t e r n i t e s w i t h a broad dark broken m e d i a l band, t a p e r i n g a n t e r i o r l y on each to a p o i n t and not q u i t e a t t a i n i n g t h e a n t e r i o r m a r g i n , and b r o a d e n i n g p o s t e r i o r l y , e s p e c i a l l y i n s t e r n i t e s 5 and 6 where i t a l m o s t c o e l e s c e s w i t h a dark l a t e r a l s t r i p e which i s s l i g h t l y m e d i a l t o t h e p a l e edge; s t e r n i t e s 8 and 9 brown w i t h s m a l l w h i t e s p o t s on t h e a n t e r i o r m a r g i n s ; g i l l s p a l e , t r a c h e a t i o n i n d i s t i n c t , d o r s a l edge s t r o n g l y c h i t i n i z e d ; t a i l s p a l e b r o w n i s h a t base and w h i t i s h a p i c a l l y , w i t h a broad deep brown median band and t i p s . D i s t r i b u t i o n ; B r i t i s h C olumbia No specimens of t h i s s p e c i e s were examined. AfflELETUS TUBERCULATUS McDUNNOUGH Ameletus t u b e r c u l a t u s fflcDunnough, fflcDunnough, 1939, Can. E n t . , 71:50 ( b i b l i o g r a p h y ) A d u l t : Wings h y a l i n e ; l o n g i t u d i n a l v e i n s brown, c r o s s v e i n s f i n e , i n c o n s p i c u o u s , and f a i n t l y shaded w i t h d a r k e r c o l o u r ; abdominal t e r g i t e s w i t h a n t e r i o r 2/3 s e m i - h y a l i n e , l i g h t smoky, s t r o n g l y v e i n e d w i t h d a r k e r , p o s t e r i o r l / 3 deep brown; two submedian dark l i n e s do not r e a c h a n t e r i o r m a r g i n s ; s t e r n i t e s p a l e d i r t y w h i t e w i t h a median row o f b l a c k g a n g l i o n i c m a r k i n g s ; male g e n i t a l i a s i m i l a r to A. c o n n e c t i n a but penes s h o r t e r and a c h a r a c t e r i s t i c l a r g e t u b e r c l e between, bases.' Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia No specimens o f t h i s s p e c i e s were examined. -40^ AMELETUS UALIDUS McDUNNOUGH Ameletus v a l i d u s McDunnough, Needham, 1935, The B i o l o g y o f M a y f l i e s , 458 ( B i b l i o g r a p h y ) A d u l t : Head and t h o r a x brown, abdomen p i n k i s h brown; wings h y a l i n e , f a i n t l y c l o u d e d w i t h p a l e umber brown i n male, v e n a t i o n d ark; s e v e r a l c r o s s v e i n s i n f o r e w i n g margined w i t h brown so t h a t wing appears s p e c k l e d ; a bdominal t e r g i t e s 1-5 semi t r a n s p a r e n t , s u t u r e s n a r r o w l y opaque; 7-10 opaque, 9 shaded l a t e r a l l y w i t h smoky brown; no g a n g l i o n i c m a r k i n g s ; penes c u r v e outward a t t i p s ; s u b a n a l p l a t e o f f e m a l e a l m o s t a t t a i n i n g p o s t e r i o r margin of t e n t h segment. Nymph: F i n e brown bands a t bases of femora and t i b i a e ; f i r s t and second femora each w i t h an o v a l brown s p o t on o u t e r s i d e , near m i d d l e ; s t e r n i t e s p a l e , w i t h f a i n t brown s t r e a k s a l o n g l a t e r a l edges of s t e r n i t e 9; g i l l s l a r g e , o v a l , p a l e , f a i n t l y t r a c h e a t e d , and w i t h t h i n dark c h i t i n o u s bands w e l l w i t h i n the d o r s a l m a r g i n s ; o u t e r t a i l s l i g h t brown, m i d d l e t a i l p a l e r and w i t h a f a i n t brown narrow median band. D i s t r i b u t i o n : A l b e r t a , B r i t i s h Columbia No specimens o f t h i s s p e c i e s were examined. AMELETUS UANCOUVERENSIS McDUNNOUGH Ameletus v a n c o u v e r e n s i s McDunnough, Needham, 1935, The B i o l o g y o f M a y f l i e s , 458 ( B i b l i o g r a p h y ) A d u l t : Deep mahogany brown s p e c i e s ; w i t h a l i g h t y e l l o w i s h brown -41-U-shaped mark on mesonotum, the base of the U on the s c u t e l l u m ; mings s t r o n g l y and e n t i r e l y t i n g e d o i i t h umber brown, s t i g m a t i c a r e a deeper; v e n a t i o n dark brown, c r o s s v e i n s numerous, th o s e i n s t i g m a anastomosed; abdominal t e r g i t e 1 mahogany brown, 2-7 s e m i - h y a l i n e , s h i n y b r i g h t y e l l o w i s h brown, shadi n g to n a r r o w l y dark brown p o s t e r i o r m a r g i n s , 8-10 opaque, mahogany brown, t i n g e d a n t e r i o r l y w i t h y e l l o w i s h brown; s t e r n i t e s 2-8 l i g h t o c h r e c u s , t i n g e d a n t e r i o r l y w i t h y e l l o w i s h brown, 9 b r i g h t y e l l o w i s h brown, dark brown a n t e r i o r l y and l a t e r a l l y ; no dark g a n g l i o n i c m a r k i n g s ; penes w i t h two l o n g sharp s p i n e s between the l a t e r a l p o r t i o n s ; t a i l s deep smoky, j o i n i n g s d a r k . Nymph; Unknown D i s t r i b u t i o n ; B r i t i s h C olumbia No specimens of t h i s s p e c i e s were examined. AIY1ELETUS VERNALIS (YlcDUNNOUGH Ameletus v e r n a l i s McDunnough, McDunnough, 1936, Can. E n t . , 68:208, ( B i b l i o g r a p h y ) A d u l t : Large s p e c i e s w i t h deep b l a c k i s h brown head and t h o r a x ; wings h y a l i n e , f o r e w i n g s shaded w i t h brown a t apex and w i t h a s l i g h t brown t i n g e a t the base of R3, where t h e r e i s a group of 6 c r o s s -v e i n s ; v e n a t i o n brown, e x c e p t 3 or 4 c o s t a l c r o s s v e i n s beyond the b u l l a which are p a l e and i n d i s t i n c t ; s t i g m a t i c c r o s s v e i n s anastomosed to form a s e r i e s of s m a l l e r c o s t a l c e l l s w i t h l a r g e r ones below; abdominal t e r g i t e s 2-6 t r a n s l u c e n t d u l l ' , g r e y i s h w h i t e , 7-10 opaque y e l l o w i s h , a l t h o u g h 9 i s brown; t e r g i t e s each w i t h a deep p u r p l e --42-brown s u b t r i a n g u l a r p a t c h , based on p o s t e r i o r m a r g i n , apex a l m o s t a t t a i n i n g a n t e r i o r m a r g i n , and brown l a t e r a l p a t c h e s ; s t e r n i t e s 2-6 w i t h f a i n t t r a c e s of m i d - v e n t r a l brown s p o t s c o n n e c t e d by a f i n e l i n e , 7 and B w i t h brown l a t e r a l p a t c h e s based on p o s t e r i o r m a r g i n s , 9 brown, y e l l o w i s h on p o s t e r i o r m a r g i n ; v/enter of female l a r g e l y t i n g e d w i t h p u r p l i s h brown; each penes w i t h a l o n g s p i n e on i n n e r s i d e . Nymph; Legs p a l e , femora w i t h l a r g e brown median p a t c h e s on o u t e r s i d e ; t i b i a e e n t i r e l y p a l e , e x c e p t at extreme base; s t e r n i t e s p a l e brown w i t h b r o a d l y p a l e l a t e r a l edges, e x c e p t i n s t e r n i t e 9 , and s m a l l p a l e d o t s near a n t e r o - l a t e r a l c o r n e r s ; g i l l s p a l e w i t h f a i n t t r a c h e a t i o n and an i n t e r i o r dark c h i t i n o u s band j u s t w i t h i n d o r s a l margin and f a i n t t r a c e s of c h i t i n o u s t h i c k e n i n g a l o n g the v e n t r a l edge; t a i l s p a l e w h i t i s h , b r o a d l y banded w i t h brown j u s t beyond m i d d l e and a t extreme t i p s . D i s t r i b u t i o n ; B r i t i s h C o l umbia No specimens of t h i s s p e c i e s were examined. APflELETUS SP. 1 Ameletus sp. 1  A d u l t ; Head dark brown, mesonotum y e l l o w i s h r e d , d a r k e r on each ^ s i d e of s c u t e l l u m ; metanotum d a r k e r ; wings amber t i n g e d , no ^ margined c r o s s v e i n s ; f o r e l e g s dark r e d d i s h brown, m i d d l e and h i n d l e g s y e l l o w - r e d ; abdominal t e r g i t e s 1 and 10 dark brown, 2-9 y e l l o w --43-r e d , d a r k e r on p o s t e r i o r m a r g i n s ; s t e r n i t e s 1 dark brown, 2-8 y e l l o w , 9 and 10 r e d d i s h brown; no dark g a n g l i o n i c m a r k i n g s . Nymph; Unknown. D i s t r i b u t i o n : B r i t i s h C olumbia M a t e r i a l Examined: 1 Male, 1 Female, B r i t i s h C o l u m b i a : C o u r t e r l a y , V I 1 1 . 3 . 3 1 , {3. S p e n c e r ) . GENUS PARAMELETUS BENGTSSON P a r a m e l e t u s , Needham, 1935, The B i o l o g y of M a y f l i e s , 502 ( B i b l i o g r a p h y ) Adult:'' Medium s i z e d b r o w n i s h m a y f l i e s , male and female ve r y s i m i l a r ; eyes o f male l a r g e , c o n t i g u o u s a p i c a l l y , n ot d i v i d e d ; f o r e l e g of male as long- as body; f i r s t j o i n t of f o r e - t a r s u s and f o r e - t i b i a t h i c k l y s e t with, b l u n t s p i n e - l i k e p r o c e s s e s , s p i n e s a t t i p s o f t a r s a l j o i n t s o f m i d d l e and h i n d l e g s ; h i n d t a r s u s s u b e q u a l to t i b i a ; c l a w s on t a r s i s i m i l a r , s h a r p - p o i n t e d ; p o s t e r i o r branch ofM of f o r e w i n g forms a l m o s t a r i g h t - a n g l e a t i t s u n i o n w i t h the stem; h i n d wing l e s s than t w i c e as l o n g as wide, median v e i n s i m p l e , not f o r k e d ; c o s t a l a n g u l a t i o n o b t u s e ; abdominal t e r g i t e s 5-9 not d i l a t e d l a t e r a l l y i n t o f l a t , b r oad • extensions'; f o r c e p s base s h a l l o w l y e x c a v a t e d on i t s a p i c a l m a r g i n , v e r y b l u n t p r o j e c t i o n s on each s i d e o f t h i s e x c a v a t i o n ; a s h o r t 5 - j o i n t e d r udiment of the m i d d l e t a i l r e m a i n s . Genotype: P a r a m e l e t u s c h e l i f e r Bengtsson -44-PARAMELETUS CDLU1YIBIAE McDUNNOUGH Pa r a m e l e t u s c o l u m b i a e McDunnouqh. McDunnough, 1938, Can. E n t . , 70: 23-34 ( B i b l i o g r a p h y ) A d u l t : (lYlale) . Wings h y a l i n e w i t h deep brown v e n a t i o n ; abdominal t e r g i t e s deep brown, p a l i n g a l o n g a n t e r i o r b o r d e r s of 1-6, 7-10 opaque, shaded w i t h l i g h t e r brown, e s p e c i a l l y l a t e r a l l y ; s t e r n i t e s the same, but r u d d i e r , , and p o s t e r i o r margins of a n t e r i o r segments b o r d e r e d n a r r o w l y w i t h d i r t y w h i t e ; b a s a l p l a t e d u l l o c h r e o u s , w i t h a U-shaped ruddy work; t a i l s smoky, p a l e r a t j o i n t s . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia No specimens of t h i s s p e c i e s were examined. GENUS SIPHLONURUS EATON Siphlonurus,Needham, 1935, The B i o l o g y of M a y f l i e s , 460 ( B i b l i o g r a p h y ) A d u l t : Male and female s i m i l a r , a p p e a r i n g a n n u l a t e o f t e n ; eyes o f male l a r g e , u s u a l l y c o n t i g u o u s a p i c a l l y , not d i v i d e d . Eyes of both s e x e s w i t h a t r a n s v e r s e band, of d i f f e r e n t c o l o u r than the eye, o b l i q u e l y a c r o s s eye; f o r e l e g of male as l o n g or s l i g h t l y l o n g e r than body; f i r s t f o r e t a r s a l j o i n t of male 3/4 t o 7/8 o f o r s u b e q u a l to second; f i r s t and second j o i n t s of f o r e t a r s u s w i t h b l u n t s p i n e -l i k e p r o c e s s e s on m a r g i n s ; sharp s p i n e s on margin o f f o r e t i b i a , and margins and t i p s of m i d d l e and h i n d t a r s i ; c l a w s s i m i l a r , s h a r p -p o i n t e d ; h i n d t a r s u s l o n g e r than h i n d t i b i a ; f o r e w i n g l o n g and narrow, -45-t h r e e t i m e s as l o n g as w i d e ; h i n d wing l e s s t h a n t w i c e as l o n g as wide; v e n a t i o n d a r k ; hemeral c r o s s v e i n s t r o n g and d a r k ; s t i g m a t i c c r o s s v e i n s f r e q u e n t l y anastomosed; c o s t a l a n g u l a t i o n of h i n d wing m e r e l y a rounded e l e v a t i o n ; median v e i n f o r k e d about l/3 t h e d i s t a n c e from the base t o the o u t e r m a r g i n ; abdominal t e r g i t e s w i t h dark t r i a n g l e s w i t h bases on p o s t e r i o r m a r g i n s , and a p i c e s not q u i t e a t t a i n i n g a n t e r i o r m a r g i n s , a l s o dark o v a l submedian s p o t s on a n t e r i o r margins i n a n t e r i o r segments, but near c e n t e r i n a p i c a l segments; s t e r n i t e s w i t h dark U-shaped marks, l a t e r a l dark t r i a n g l e s which may o r may not be u n i t e d a t b a s e s , or a c o n t i n u o u s o r d i s -c o n t i n u o u s dark median l i n e , w i t h one o r two p a i r s of s m a l l d o t s near i t ; f o r c e p s base very l o n g , s l i g h t l y concave i n i t s a p i c a l m a r g i n ; b a s a l j o i n t o f f o r c e p s an i m p e r f e c t l y s e p a r a t e d r i n g - l i k e e n largement o f the l o n g j o i n t ; two d i s t a l j o i n t s t o g e t h e r not l o n g e r t h a n the l o n g j o i n t ; the i n n e r a p i c a l margin of the b a s a l j o i n t o f t e n extended l a t e r a l l y beyond the base of the l o n g j o i n t ; penes complex, c o n s i s t i n g u s u a l l y of p a i r e d v e n t r a l and d o r s a l c h i t i n i z e d p o r t i o n s , of which one p a i r c o m p l e t e l y o v e r l i e s t h e o t h e r ; from b e n e a t h , the penes not u s u a l l y seen above the a p i c a l margin o f f o r c e p s base; s u b a n a l p l a t e of female b r o a d , convex i n i t s a p i c a l m a r g i n . Nymph: Compressed, s t r e a m l i n e d body; m a x i l l a r y and l a b i a l p a l p i 3 - j o i n t e d ; m a x i l l a c o n i c a l a t apex, w i t h a few s i m p l e h a i r s and s p i n e s on o u t e r and i n n e r m a r g i n s ; f r o n t a l margin of labrum e n t i r e and -46-s l i g h t l y concave; no s p i n e s on head or pronotum; clauis l o n g and s l e n d e r , not p e c t i n a t e , m e s o t h o r a c i c and m e t a t h o r a c i c c l a w s not l o n g e r than the p r o t h o r a c i c c l a w s ; w e l l - d e v e l o p e d p o s t e r o - l a t e r a l s p i n e s on the t h i n f l a t t e n e d l a t e r a l m a r gins o f the abdominal t e r g i t e s ; g i l l s l a r g e and p l a t e l i k e , r e t u s e on a p i c a l m a r g i n s ; t r a c h e a t i o n abundant; g i l l s double on segments 1 and 2 o r on segments 1-7; l a m e l l a e e q u a l i n s i z e , e x c e p t on segment 7. Genotype: S i p h l o n u r u s f l a v i d u s ( i n B a e t i s ) Ed. P i c t e t SIPHLONURUS  Key To A d u l t s 1. Abdominal s t e r n i t e s l a r g e l y dark 2. Abdominal s t e r n i t e s l a r g e l y p a l e 3. 2. C o s t a l i n t e r c a l a r i e s j o i n i n g C u l t o h i n d margin of f o r e w i n g f o r k e d Isp. 1 C o s t a l i n t e r c a l a r i e s j o i n i n g C u l to h i n d margin of f o r e w i n g not f o r k e d . a u t u m n a l i s IYlcD 3. No U-shaped marks on abdominal s t e r n i t e s p . 2 U-shaped marks on abdominal s t e r n i t e s 4. 4. U-shaped marks on s t e r n i t e s 8-9 d i f f u s e d and p o o r l y d e f i n e d . P a l e ruddy s p o t on r e a r o f mesonotum .columbianus fflcD U-shaped marks c l e a r l y d e f i n e d on s t e r n i t e s 8-9. No ruddy s p o t on mesonotum... o c c i d e n t a l i s Eaton Key To Nymphs 1. Legs unbanded. UJide p a l e v e r t i c a l band between antennae b a s e s . G i l l s on segments 1-2 double 2. -47-Legs banded. No p a l e band between antennae b a s e s . G i l l s d o uble on segments 1-2 o r segments 1-7. .• 4. 2. T a i l s p a l e , w i t h dark p r o x i m a l and m e d i a l t r a n s v e r s e bands. S m a l l U-shaped dark markings on s t e r n i t e s . A l l t e r g i t e s d a r k l y p a t t e r n e d sp. 4 T a i l s p a l e , w i t h a dark m e d i a l t r a n s v e r s e band. V e n t e r o f abdomen w i t h no dark m a r k i n g s . A l l t e r g i t e s not d a r k l y p a t t e r n e d .3. 3. T e r g i t e s 2, 3, 6, 7, and 9 p r e d o m i n a n t l y d a r k l y p a t t e r n e d , o t h e r s p a l e . G i l l t r a c h e a t i o n p a l e . . . . ...sp. 3 A l l t e r g i t e s w i t h a p a l e median t r i a n g u l a r and p a l e l a t e r a l m a r k i n g s . G i l l t r a c h e a t i o n dark • .sp. 5 4. G i l l s double on segments 1-2 o n l y o c c i d e n t a l i s Eaton G i l l s d o u b l e on segments 1-7. 5. 5. T a i l s unbanded. No p a t t e r n on t e r g i t e s or s t e r n i t e s sp. 6 T a i l s banded. T e r g i t e s or s t e r n i t e s p a t t e r n e d ....6. 6. T a i l s p a l e , w i t h a v e r y narrow dark m e d i a l band. L a t e r a l t r a n s v e r s e dark bands on a l l t e r g i t e s e x c e p t 5 and 8, which are, p a l e . S t e r n i t e s u n i c o l o u r e d . D o r s a l g i l l s p a t t e r n e d . .sp. 7 T a i l s not as above. A l l t e r g i t e s d ark. S t e r n i t e s p a t t e r n e d . G i l l t r a c h e a t i o n dark ...7. 7. T a i l s p a l e , w i t h p r o x i m a l , m e d i a l , and a p i c a l dark t r a n s v e r s e bands. S t e r n i t e s w i t h two s m a l l dark o b l i q u e l i n e s and two m e d i a l and two l a t e r a l dark s p o t s . M e d i a l dark l i n e on v e n t e r . . sp. 8 -48-T a i l s p a l e , w i t h m e d i a l and a p i c a l dark t r a n s v e r s e bands. S t e r n i t e s w i t h dark s u b m e d i a l e l o n g a t s . s p o t s . T e r g i t e s dark w i t h dark t r a n s v e r s e l a t e r a l bands s p . 9 Unknown S. a u t u m n a l i s McD S. c o l umbianus McD SIPHLONURUS AUTUMNALIS McDUNNOUGH  S i p h l o n u r u s a u t u m n a l i s fflcDunnough, Needham, 1935, The B i o l o g y of M a y f l i e s , 467. ( B i b l i o g r a p h y ) A d u l t : A l a r g e dark s p e c i e s ; head and m e s o n o t a l s c u t e l l u m and sternum b l a c k i s h ; pronotum deep smoky; mesonotum dark .brown, p l e u r a l s u t u r e s p a l e y e l l o w i s h ; wings h y a l i n e ; v e n a t i o n deep brown; c o s t a l c r o s s -v e i n s i n b a s a l 2/3 of c o s t a l space weak; s t i g m a t i c c r o s s v e i n s heavy and s t r o n g l y anastomosed; abdominal t e r g i t e s deep p u r p l i s h brown; a n t e r i o r t r i a n g l e s t i n g e d w i t h y e l l o w ; l a t e r a l m a r g i n s , e s p e c i a l l y o f the f o u r a p i c a l segments, n a r r o w l y y e l l o w i s h ; s t e r n i t e s deep p u r p l i s h brown, p o s t e r i o r margins n a r r o w l y y e l l o w i s h ; p o s t e r o - m e d i a l a r e a o f s t e r n i t e 9 y e l l o w i s h ; a p i c a l margin of f o r c e p s base weakly e x c a v a t e d . Nymph: Unknown D i s t r i b u t i o n : A l b e r t a , B r i t i s h C olumbia M a t e r i a l Examined: 1 M a l e , B r i t i s h C o l u m b i a : B a r k e r v i l l e , V I I . 7 . 4 8 . (H.R. McCarthy) -49-SIPHLONURUS COLUiYiBIANUS McDUNNOUGH S i p h l o n u r u s c o l umbianus McDunnough. Needham, 1935, The B i o l o g y of M a y f l i e s , 469 ( B i b l i o g r a p h y ) A d u l t : A l a r g e dark s p e c i e s ; p a l e ruddy s p o t a n t e r i o r t o b l a c k m e s o t h o r a c i c s c u t e l l u m ; wings h y a l i n e ; f a i n t b r o w n i s h t i n g e i n s t i g m a t i c a r e a ; v e n a t i o n b l a c k i s h ; a bdominal t e r g i t e s deep p u r p l i s h brown, a n t e r i o r t e r g i t e s y e l l o w i s h ; s t e r n i t e s d u l l y e l l o w i s h ; U-shaped marks p u r p l i s h brown, d i f f u s e and p o o r l y d e f i n e d on s t e r n i t e s 8 and 9, s t e r n i t e 10 w h o l l y brown; two t i n y d o t s u s u a l l y near c e n t e r o f each s t e r n i t e ; t a i l s dark b a s a l l y , p a l e r d i s t a l l y ; j o i n i n g s brown. Nymph: Unknown D i s t r i b u t i o n : B r i t i s h C o l u m b i a , C a l i f o r n i a No specimens of t h i s s p e c i e s were examined. SIPHLONURUS OCCIDENTALIS EATON S i p h l o n u r u s o c c i d e n t a l i s E a t o n , Needham, 1935, The B i o l o g y o f M a y f l i e s , 473 ( B i b l i o g r a p h y ) A d u l t : A l a r g e r e d d i s h and y e l l o w i s h brown s p e c i e s ; head and t h o r a x y e l l o w i s h brown; pronotum dark brown,grey l a t e r a l l y ; m e s o n o t a l s c u t e l l u m and l a t e r a l m argins dark r e d d i s h brown, y e l l o w a r e a s a n t e r i o r t o m e s o n o t a l and m e t a n o t a l s c u t e l l a ; a n t e r o - l a t e r a l c o r n e r s o f mesonotum and p l e u r a l s u t u r e s y e l l o w i s h , o f t e n w i t h orange -50' m a r k i n g s ; w h i t e bands a c r o s s mesa and m e t a s t e r n a j wings h y a l i n e ; v e n a t i o n p u r p l i s h b l a c k ; l o n g i t u d i n a l v e i n s , h e a v i e r ; t h i c k e n e d a r e a s on b u l l a , Sc, R, and f i r s t d i v i s i o n o f Rs; narrow brown s h a d i n g a t base of f o r e w i n g , c o s t a l and s u b c o s t a l c r o s s v e i n s p a l e ; s t i g m a t i c c r o s s v e i n s numerous, o f t e n f o r k i n g near c o s t a l m a r g i n ; median p o r t i o n of each abdominal t e r g i t e y e l l o w i s h brown; l a t e r a l t r i a n g l e s d a r k , p r o m i n e n t , c o n f i n e d to p o s t e r o - l a t e r a l a n g l e s and l a t e r a l m a r g i n s ; dark o v a l s p o t s c o n s p i c u o u s and r e d d i s h brown; p a l e a r e a s s e m i -h y a l i n e ; a l l t e r g i t e s p a l e on p o s t e r i o r m a r g i n s ; a p i c a l t e r g i t e s marked w i t h y e l l o w , o f t e n w i t h powdery a r e a s ; U-marks on s t e r n i t e s c o n s p i c u o u s , the arms may be u n i t e d p o s t e r i o r l y by a brown c r e s c e n t i c or s t r a i g h t t r a n s v e r s e band; two s m a l l dark s p o t s w i t h i n each U-mark, a n t e r i o r t o c e n t e r ; t a i l s dark p u r p l i s h brown b a s a l l y , r e s t y e l l o w i s h o r w h i t i s h , j o i n i n g s s l i g h t l y d a r k e r . Nymph: Legs banded a l t e r n a t e l y l i g h t and dark; dark U-shaped markings on each abdominal s t e r n i t e ; g i l l s double on segments 1 and 2 o n l y ; t a i l s p a l e , dark banded a t t i p o n l y . D i s t r i b u t i o n : B r i t i s h C olumbia M a t e r i a l Examined: 1 ( ? ) B r i t i s h C o l u m b i a : Desmond, V I I I . 2 9 . 3 7 (O.K. Oacob) S i p h l o n u r u s sp.- 1  A d u l t : A v e r y l a r g e dark s p e c i e s ; head and t h o r a x dark brown; f o r e w i n g s - 5 1 -w i t h f o r k e d i n t e r c a l a r i e s j o i n i n g C u l t o h i n d m a r g i n ; abdominal t e r g i t e s and s t e r n i t e s b l a c k w i t h y e l l o w p o s t e r i o r m a r g i n s ; no U-shaped dark markings on s t e r n i t e s . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h C o l umbia M a t e r i a l Examined: 1 Female, B r i t i s h C o l u m b i a : Cowichan, VI.20.49 (G.S. Brown) S i p h l o n u r u s sp. 2  A d u l t : UJings h y a l i n e , u n p a t t e r n e d ; abdominal t e r g i t e s 3-6 o n l y p a l e y e l l o w i s h brown, each w i t h two s u b m e d i a l t r i a n g l e s brown; t e r g i t e s 1-2 and 7-10 brown, p o s t e r i o r b o r d e r s b l a c k ; s t e r n i t e s 2-8 p a l e , w i t h dark g a n g l i o n i c m a r k i n g s , 9-10 dark brown; no U-shaped m a r k i n g s ; t a i l s p a l e , d a r k e r a t j o i n i n g s . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: 1 M a l e , B r i t i s h C o l u m b i a : T r i n i t y V a l l e y * V I I . 2 . 4 3 (C.V. Morgan) S i p h l o n u r u s s p . 3 A d u l t : Unknown Nymph: A wide p a l e v e r t i c a l band between antennae b a s e s ; l e g s unbanded; abdominal t e r g i t e s 2, 3, 6, 7, and 9 p r e d o m i n a n t l y d a r k l y p a t t e r n e d , -52-o t h e r s p a l e ; g i l l s d ouble on segments 1 and 2 o n l y ; t r a c h e a t i o n p a l e ; no U-shaped markings on s t e r n i t e s ; t a i l s p a l e , w i t h a dark median t r a n s v e r s e band. E c o l o g y : Nymphs of t h i s s p e c i e s were t a k e n from t h e edge of t h e A l o u e t t e R i v e r a t a depth of 1 t o 2 f e e t . The c u r r e n t was s l o w and the r i v e r bed c o n s i s t e d o f a m i x t u r e o f c o a r s e and f i n e g r a v e l , sand, mud, and o r g a n i c s i l t and d e b r i s . A l l specimens were t a k e n d u r i n g mid-3une. D i s t r i b u t i o n : B r i t i s h C olumbia M a t e r i a l Examined: 7 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) y i . ? . 5 g (N. F i l m e r ) , Canim Lake, VI.27.61 (G.G.E. S c u d d e r ) . S i p h l o n u r u s s p . 4  A d u l t : Unknown Nymph: Wide p a l e band between antennae b a s e s , l e g s unbanded; a l l t e r g i t e s d a r k l y p a t t e r n e d ; U-shaped markings on s t e r n i t e s ; g i l l s d o u b l e on segments 1 and 2 o n l y ; t r a c h e a t i o n dark; t a i l s w i t h p r o x i m a l and median dark bands. D i s t r i b u t i o n : B r i t i s h C olumbia M a t e r i a l Examined: 2 Nymphs, B r i t i s h C o l u m b i a : Canim Lake, VI.27.61 (G.G.E. Sc u d d e r ) -53-' S i p h l o n u r u s s p . 5  A d u l t ; Unknown IMymph; UJide p a l e band between antennae bas e s ; l e g s unbanded; t e r g i t e s w i t h p a l e t r i a n g u l a r and l a t e r a l marks; no marks on s t e r n i t e s ; g i l l s double on segments 1 and 2 o n l y ; t r a c h e a t i o n dark; t a i l s w i t h dark median band. D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: 1 Nymph, B r i t i s h C o l u m b i a : Canim Lake, VI.27.61 (G.G.E. Scudder) S i p h l o n u r u s s p . 6  A d u l t ; Unknown Nymph: Legs banded; no p a t t e r n on t e r g i t e s o r s t e r n i t e s ; g i l l s double on segments 1 t o 7; no t r a c h e a t i o n ; t a i l s unbanded. D i s t r i b u t i o n ; B r i t i s h C olumbia M a t e r i a l Examined: 6 Nymphs, B r i t i s h C o l u m b i a : N i c o l a Creek. S i p h l o n u r u s s p . 7  A d u l t ; Unknown Nymph: Legs banded; t e r g i t e s w i t h l a t e r a l t r a n s v e r s e dark bands; t e r g i t e s 5 and 8 p a l e ; s t e r n i t e s u n i c o l o u r e d , w i t h no p a t t e r n ; g i l l s double on segments 1 t o 7, d o r s a l g i l l s p a t t e r n e d ; t a i l s w i t h a v e r y narrow -54-dark m e d i a l band. D i s t r i b u t i o n : B r i t i s h C o l umbia m a t e r i a l Examined: 19 Nymphs, B r i t i s h C o l u m b i a : N i c o l a Creek. S i p h l o n u r u s s p . 3  A d u l t : Unknown ' Nymph: Legs banded; t e r g i t e s d a r k l y p a t t e r n e d ; s t e r n i t e s w i t h two s m a l l o b l i q u e l i n e s and two m e d i a l and two l a t e r a l dark s p o t s , s p o t s may be p a l e r ; dark m e d i a l l i n e on s t e r n i t e s ; g i l l s d o u b l e on segments 1 t o 7; t r a c h e a t i o n d a r k ; t a i l s w i t h p r o x i m a l , m e d i a l and a p i c a l dark bands. D i s t r i b u t i o n : B r i t i s h Columbia m a t e r i a l Examined: 4 Nymphs, B r i t i s h C o l u m b i a : n r . Rock Lake, VII.16.62 (G.G.E. ' S c u d d e r ) . S i p h l o n u r u s s p . 9  A d u l t : Unknown Nymph: Legs banded; abdominal t e r g i t e s dark w i t h d a r k e r l a t e r a l t r a n s v e r s e bands; s t e r n i t e s w i t h dark s u b m e d i a l e l o n g a t e s p o t s ; g i l l s double.on segments 1 t o 7; t r a c h e a t i o n d a r k ; t a i l s w i t h median and a p i c a l dark bands. -55-D i s t r i b u t i o n ; 8 r i t i s h C olumbia M a t e r i a l Examined: 6 Nymphs, B r i t i s h C o l u m b i a : 5 Brunson Lake, VI.25.61 (G.G.E. Scu d d e r ) 1 W i l l i a m s Lake, VI.24.61 (G.G.E. Scudder) SUBFAMILY HEETAGENIINAE A d u l t : Eyes o f males s i m p l e ; h i n d t a r s i w i t h f i v e f r e e l y movable j o i n t s ; wing v e n a t i o n p l e n t i f u l i n both w i n g s ; two p a r a l l e l p a i r s o f c u b i t a l i n t e r c a l a r i e s , u n a t t a c h e d b a s a l l y , i n f o r e w i n g , the p a i r n e a r e s t the h i n d a n g l e i s l o n g e r ; o u t e r f o r k of Rs o f h i n d wing p r e s e n t ; f o r c e p s 4 - j o i n t e d . Nymphs: F l a t t e n e d , p r o t e c t i v e l y c o l o u r e d nymphs; heads s t r o n g l y d e p r e s s e d ; eyes l a t e r a l ; labrum c o n s i d e r a b l y w i d e r t h a n l o n g ; m a n d i b l e s s l e n d e r i n b a s a l h a l f ; two c a n i n e s , the o u t e r l o n g e r t h a n the i n n e r ; c a n i n e s scoop-shaped, margins more o r l e s s c r e n a t e , may be one or two sharp s p i n e s on t i p of i n n e r c a n i n e ; l a c i n i a p r e s e n t or a b s e n t , i f a b s e n t , a row o f h a i r s o f t e n i n l a c i n i a l r e g i o n ; m a x i l l a r y p a l p i t w o - j o i n t e d , d i s t a l j o i n t o f t e n t h i c k l y s e t w i t h a p i c a l s p i n e s ; i n n e r m a r g i n of g a l e a - l a c i n i a w i t h a f r i n g e of l o n g h a i r s u s u a l l y a second row p a r a l l e l to t h e s e a s h o r t d i s t a n c e back from m a r g i n ; upper margin or crown of g a l e a - l a c i n i a w i t h s p i n e s o r h a i r s , o r b o t h ; l a b i a l p a l p i s i m i l a r to m a x i l l a r y p a l p i ; g i l l s p r e s e n t on abdominal segments 1-7; g i l l s d o u b l e , c o n s i s t i n g o f a d o r s a l l a m e l l a t e and a v e n t r a l f i b r i l l a n p o r t i o n , l a t t e r may be w a n t i n g , much r e d u c e d , o r pushed upwards t o appear t o l i e d o r s a l t o l a m e l l a t e p o r t i o n . . . -56-SUBFAmiLY HEPTAGENIINAE  Key To A d u l t s 1. B a s a l j o i n t of f o r e t a r s u s o f male not as l o n g as second j o i n t 2. B a s a l j o i n t o f . f o r e t a r s u s of male e q u a l t o or s l i g h t l y l o n g e r than second j o i n t Epeorus Eaton 2. B a s a l j o i n t of f o r e t a r s u s o f male 2/3 t o 3/4 as l o n g as second j o i n t . 3. B a s a l j o i n t of f o r e t a r s u s of male l / 6 to l / 2 as l o n g as second j o i n t 4. 3. S t i g m a t i c a r e a o f ' f o r e w i n g d i v i d e d by a f i n e l i n e i n t b an upper and lower s e r i e s of c e l l u l e s . B a s a l c o s t a l c r o s s v e i n s v e r y weak Cinyqma Eaton" S t i g m a t i c a r e a of f o r e w i n g not d i v i d e d by a f i n e l i n e i n t o an upper and' lower s e r i e s o f c e l l u l e s . B a s a l c o s t a l c r o s s v e i n s u s u a l l y w e l l - d e v e l o p e d . . . . . . Cinyqmula filcD 4. S t i g m a t i c c r o s s v e i n s more or l e s s anastomosed. Eyes of male u s u a l l y c o n t i g u o u s . . . R i t h r o q e n a Eaton S t i g m a t i c c r o s s v e i n s net anastomosed. Eyes of male not c o n t i g u o u s 5. 5. B a s a l j o i n t o f f o r e t a r s u s of male l / 6 to l / 3 as l o n g as the second j o i n t . Penes not d i s t i n c t l y L-shaped. S t i g m a t i c c r o s s -v e i n s not s l a n t e d H e p t a q e n i a Walsh B a s a l j o i n t o f f o r e t a r s u s o f male l / 3 to l / 2 as l o n g as the second j o i n t . Penes more or. l e s s d i s t i n c t l y L-shaped. S t i g m a t i c c r o s s v e i n s v a r i a b l y s l a n t e d .Stenonema T r a v e r -57-Key To Nymphs 1. Three t a i l s ,2. Two t a i l s Epeorus Eaton 2. G i l l s o f s e v e n t h p a i r o f g i l l s f l a t and p l a t e - l i k e , q u i t e s i m i l a r t o p r e c e d i n g p a i r s . Tracheae w i t h l a t e r a l branches always p r e s e n t i n s e v e n t h p a i r . E i t h e r s p i n e s or h a i r s on crown o f g a l e a - l a c i n i a , but not both 3. G i l l s of s e v e n t h p a i r of g i l l s r e d uced t o a s i n g l e s l e n d e r t a p e r e d f i l a m e n t on s p i n e . T r a c h e a e , i f p r e s e n t i n t h i s f i l a m e n t , w i t h o u t l a t e r a l b r a n c h e s . Both s p i n e s and h a i r s on crown o f g a l e a - l a c i n i a . .Stenonema T r a v e r 3. G i l l s o f f i r s t and second segments s m a l l e r t h a n r e s t , a l l g i l l s d i r e c t e d l a t e r a l l y , o r d o r s a l l y and l a t e r a l l y , n ot c o n v e r g i n g beneath body. F i b r i l l a r g i l l s v e n t r a l 4. G i l l s o f f i r s t and l a s t segments much e n l a r g e d , c o n v e r g i n g beneath body of nymph. F i b r i l l a r g i l l s d o r s a l R i t h r o q e n a Eaton 4. F i b r i l l a r p o r t i o n of g i l l s w e l l d e v e l o p e d on segments 1 to 6, may be wanting on segment. F r o n t o f h e a d e n t i r e o r v e r y s l i g h t l y e m a r g i n a t e . . 5. F i b r i l l a r p o r t i o n o f g i l l s r educed t o a few t i n y t h r e a d s . F r o n t o f head d i s t i n c t l y e m a r g i n a t e Cinyqmula fYlcD 5. A c h i t i n i z e d a r e a on each mandible below molar r e g i o n . I n n e r c a n i n e l / 2 as l o n g as o u t e r . H a i r s on crown o f g a l e a - l a c i n i a . L a t e r a l s p i n e s a b s e n t . Labrum e x t e n d i n g not more th a n l / 4 d i s t a n c e a l o n g a n t e r i o r margin of head Cinyqma Eaton -58-No c h i t i n z e d a r e a on m a n d i b l e . Inner c a n i n e a t l e a s t 3/4 as l o n g as o u t e r . S p i n e s on crouin o f g a l e a - l a c i n i a . Labrum e x t e n d i n g 2/3 t o 3/4 d i s t a n c e a l o n g a n t e r i o r margin of head H e p t a q e n i a Walsh GENUS CINYGfflA EATON Cinyqma, Needham, 1935, The B i o l o g y of M a y f l i e s , 365 ( B i b l i o g r a p h y ) A d u l t : Eyes of male not c o n t i g u o u s ; f o r e l e g of male as l o n g as body; femur s l i g h t l y s h o r t e r than t i b i a , w hich i s about l / 2 the l e n g t h o f the t a r s u s ; b a s a l f o r e t a r s a l j o i n t 2/3 t o 3/4 as l o n g as t h e second, which i s s u b e q u a l to t h i r d ; f o u r t h j o i n t about 3/4 as l o n g as the t h i r d ; f i f t h j o i n t l / 2 as l o n g as f i r s t ; i n h i n d t a r s u s b a s a l j o i n t s l i g h t l y l o n g e r t h a n second; f i f t h j o i n t s l i g h t l y l o n g e r than b a s a l j o i n t ; a l l c l a w s d i s s i m i l a r ; s t i g m a t i c a r e a of f o r e w i n g d i v i d e d by a f i n e l i n e i n t o a s e r i e s of s m a l l c o s t a l and l a r g e r s u b c o s t a l c e l l s ; b a s a l c o s t a l c r o s s v e i n s v e r y weak; s t i g m a t i c c r o s s -v e i n s s l a n t e d ; p o s t e r i o r branch of IYI i n f o r e w i n g forms a l m o s t a r i g h t a n g l e a t i t s u n i o n w i t h the a n t e r i o r b r a n c h ; o u t e r f o r k o f Rs o f h i n d wing p r e s e n t ; a p i c a l margin of f o r c e p s base not d e e p l y e x c a v a t e d ; f o r c e p s 4 - j o i n t e d , u n i t e d a l m o s t t o base; a p a i r o f s m a l l median s p i n e s on bases of penes, and a s m a l l e r s p i n e on each d i v i s i o n , below apex; p o s t e r i o r margin of s u b a n a l p l a t e i n female r e t u s e . Nymph: F r o n t o f head e n t i r e o r s l i g h t l y e m a r g i n a t e ; labrum e x t e n d i n g not more than l / 4 the d i s t a n c e a l o n g the a n t e r i o r margin o f the head; mandible not v i s i b l e d o r s a l l y ; a c h i t i n i z e d a r e a basad of m o l a r a r e a of each m a n d i b l e ; i n n e r c a n i n e l / 2 as l o n g as o u t e r ; h a i r s on crown of g a l e a - l a c i n i a ; m a x i l l a r y p a l p i u s u a l l y not v i s i b l e d o r s a l l y ; g l o s s a e of l a b i u m d i s t i n c t l y t r i a n g u l a r ; , g i l l s on a l l segments d i r e c t l y l a t e r a l l y , 1 s t p a i r and 7 t h p a i r s m a l l e r than o t h e r s ; no f i n g e r l i k e p r o j e c t i o n s on g i i l l a m e l l a e ; f i b r i l l a r p o r t i o n o f g i l l s w e l l d e v e l o p e d on segments 1-6, may be w a n t i n g on segment 7, l o n g e r than l a m e l l a e on segment 1; a l l f i b r i l l a r p o r t i o n s v e n t r a l ; t h r e e t a i l s . Genotype; Cinyqma;. i n t e g r u m Eaton CINYG1Y1A INTEGRUM EATON Cinyqma i n t e g r u m E a t o n , S p i e t h , 1941, Ann. E n t . Soc. Amer., 34:88 ( B i b l i o g r a p h y ) A d u l t ; Reddish-brown s p e c i e s ; wings h y a l i n e , t i n g e d w i t h f a i n t g r e y i s h i n s t i g m a t i c a r e a and b a s a l a r e a ; v e n a t i o n dark brown; abdominal t e r g i t e s p a l e r h y a l i n e ; t e r g i t e 2 p u r p l i s h brown; t e r g i t e s 3-7 w i t h a median p u r p l e - b r o w n s t r i p e and a p a i r of subrnedial s t r i p e s , a p a l e c r e s e n t i c a r e a between t h e s e and the median s t r i p e ; s t e r n i t e w i t h p a l e p u r p l i s h brown t i n g e or l i g h t burnt-umber. Nymph: Unknown D i s t r i b u t i o n ; Oregon, B r i t i s h Columbia No specimens o f t h i s s p e c i e s were examined. -60-GENUS CINYGfflULA lYIcDUNNDUGH Ci n y q m u l a , Needha'm, 1935, The B i o l o g y o f m a y f l i e s , 384 ( B i b l i o g r a p h y ) A d u l t ; Eyes of male not c o n t i g u o u s , but s e p a r a t e d o n l y by a space l e s s t h a n l / 3 the s h o r t e r d i a m eter of the eye; f o r e l e g of male l o n g e r t h a n male; of f e m a l e , as l o n g as the body; f o r e femur of male 3/4 as l o n g as t i b i a ; which i s 2/3 t o 3/4 the l e n g t h of the t a r s u s ; b a s a l f o r e t a r s a l j o i n t 2/3 to 3/4 the l e n g t h o f the second, b a s a l j o i n t o f h i n d t a r s u s i n both sexes s l i g h t l y l o n g e r t h a n the second j o i n t , d i s t a l j o i n t e q u a l to f i r s t and second combined; f o r e c l a w s i n male b l u n t , d i s s i m i l a r i n m i d d l e and h i n d l e g s of male, on a l l l e g s o f f e m a l e ; s t i g m a t i c a r e a o f f o r e w i n g not d i v i d e d by a f i n e l i n e i n t o an upper and lower s e r i e s o f c e l l u l e s ; s t i g m a t i c c r o s s v e i n s u s u a l l y not anastomosed, but s t u n t e d , b a s a l c o s t a l c r o s s -v e i n s u s u a l l y w e l l - d e v e l o p e d ; o u t e r f o r k of Rs of h i n d wing p r e s e n t ; penes r o d - l i k e , s e p a r a t e d a l m o s t t o base; a p a i r of s h o r t s p i n e s , o f t e n o u t c u r v e d s l i g h t l y , u s u a l l y on i n n e r a p i c a l m a r g i n , o f t e n a s i n g l e s p i n e on each lower o u t e r m a r g i n ; s u b a n a l p l a t e of female w i t h a U-shaped c l e f t i n a p i c a l m a r g i n . Nymph; F r o n t of head e m a r g i n a t e , e x p o s i n g mouthparts when viewed d o r s a l l y ; mandible not v i s i b l e d o r s a l l y ; i n n e r c a n i n e l / 4 the l e n g t h of the o u t e r ; s p i n e s on crown of the l a c i n i a - g a l e a ; g i l l s on segments 1-7, d i r e c t l a t e r a l l y ; g i l l s on segment 1 l a r g e s t f i b r i l l a r p o r t i o n v e n t r a l , r e d u c e d t o a few t i n y t h r e a d s ; no f i n g e r l i k e p r o j e c t i o n s on l a m e l l a e ; p o s t e r o - l a t e r a l margins o f abd o m i n a l t e r g i t e s -61-s l i g h t l y p roduced; t a i l s t h r e e . Genotype: Cinyqmula r a m a l e y i ( E c d y u r u s ) Dodds. C IN YG1Y1UL A  Key To A d u l t s 1. C r o s s v e i n s margined w i t h broiun 2. C r o s s v e i n s not margined 3. 2. C r o s s v e i n s i n c o s t a l h a l f o f f o r e w i n g o n l y s l i g h t l y margined w i t h brown. UJings t i n g e d w i t h amber a t base and a l o n g c o s t a l margin o f both w ings.. q a r t r e l l i IYlcD C r o s s v e i n s v e r y f i n e and brown, more d i s t i n c t i n p t e r o s t i g m a t i c a r e a . UJings h y a l i n e w i t h t r a c e s of b l a c k i s h s h a d i n g a t extreme bas e . . . . . . . . k o o t e n a i IYlcD 3. V e n t r a l m e d i a l marks absent mimus ( E a t o n ) V e n t r a l m e d i a l marks p r e s e n t 4. 4. One o r more s p i n e s s u b a p i c a l l y on each d i v i s i o n of penes, on i n n e r m a r g i n s . . .....5. L a t e r a l s p i n e s p r e s e n t on lower o u t e r margins of penes par ( E a t o n ) 5. Two l o b e s a t apex o f each d i v i s i o n o f penes, the l o n g e r d i r e c t e d l a t e r a l l y r a m a l e y i (Dodds) A s i n g l e w e l l - d e f i n e d l o b e on apex of each d i v i s i o n o f penes u n i f o r m u s (IYlcD) Key To Nymphs 1. A p i c a l abdominal t e r g i t e s same c o l o u r as the o t h e r s s p . 1 A p i c a l abdominal t e r g i t e s p a l e r than the o t h e r s ..2. 2. A p i c a l abdominal t e r g i t e s w h i t e . Femora brown w i t h a p a l e -62-L-shaped o r V-shaped l o n g i t u d i n a l mark on each b a s a l h a l f . . . . 3 . A p i c a l abdominal t e r g i t e s may be p a l e r t h a n the p r e c e d i n g ones, but each has a narrow dark a n t e r i o r m a r g i n . Femora o c h r e o u s , w i t h two broad brown bands U Q i f o r m d s (IYlcD) 3. P a l e f e m o r a l mark L-shaped , . r a m a l e y i (Dodds) P a l e f e m o r a l mark V-shaped.. sp.2 Unknown: Cinyqmula q a r t r e l l i filcD Cinyqmula mimus ( E a t o n ) Cinyqmula par ( E a t o n ) Cinyqmula k o o t e n a i fflcD CIMYGmULA GARTRELLI (YlcDUNNOUGH Cinyqmula q a r t r e l l i OflcDunnough, Needham, 1935, The B i o l o g y of M a y f l i e s , 388 ( B i b l i o g r a p h y ) A d u l t : A medium s i z e d brown s p e c i e s ; a w i n e - c o l o u r e d p a t c h a n t e r i o r to base of f o r e w i n g from which a p a l e o c h r e o u s dash p r o j e c t s towards the pronotum; wings h y a l i n e ; t i n g e d w i t h amber a t base and a l o n g c o s t a l m argin; c r o s s v e i n s i n c o s t a l h a l f of f o r e w i n g o n l y s l i g h t l y margined w i t h brown; abdominal t e r g i t e 1 deep brown; t e r g i t e s 2-7 p a l e s e m i - h y a l i n e , p o s t e r i o r p o r t i o n s deep r e d d i s h brown; t e r g i t e s 8-10 opaque dark brown, w i t h p a l e l a t e r a l p a t c h e s on t e r g i t e s 8 and 9; s t e r n i t e s l i g h t - y e l l o w i s h brown w i t h p o s t e r i o r m a r g i n s , and o f t e n t h e t h r e e a p i c a l segments, f a i n t l y t i n g e d w i t h r e d d i s h ; f a i n t g a n g l i o n i c m a r k i n g s ; a s i n g l e w e l l d e f i n e d l o b e on apex of each d i v i s i o n of penes, each w i t h a s m a l l v e n t r a l s p i n e -63-on the i n n e r m a r g i n ; median a p i c a l s p i n e s s l i g h t l y s e r r a t e on o u t e r m a r g i n s . Nymph; Unknown D i s t r i b u t i o n : B r i t i s h C o l umbia No specimens of t h i s s p e c i e s were examined. CINYGffiULA KOOTENAI fflcDUNNOUGH Cinyqmula k o o t e n a i fYlcDunnouqh, fflcDunnough, 1943, Can.Ent. 75:3 ( B i b l i o g r a p h y ) A d u l t : Wings h y a l i n e ; w i t h t r a c e s o f b l a c k i s h s h a d i n g a t extreme base; v e n a t i o n f i n e , brown; 4 or 5 e x t r e m e l y f a i n t c r o s s v e i n s b e f o r e t h e b u l l a ; s t i g m a t i c c r o s s v e i n s more d i s t i n c t , w i t h o n l y an o c c a s i o n a l t r a c e o f anastomoses; penes bent outward i n a p i c a l h a l f ; t he v e r y d i s t i n c t i v e s t i m u l i a r e v e r y l o n g , t h i n , and c u r v e d i n w a r d s i n t h e i r a p i c a l p o r t i o n s . Nymphs: Unknown D i s t r i b u t i o n : B r i t i s h C olumbia No specimens of t h i s s p e c i e s were examined. CINYGITIULA ffllMUS (EATON) Cinyqmula mimus ( E a t o n ) , S p i e t h , 1941, Ann. E n t . Soc. Amer., 34:89 ( B i b l i o g r a p h y ) a d u l t : A l a r g e p u r p l i s h brown s p e c i e s ; p a l e y e l l o w i s h o r creamy a r e a s a n t e r i o r and v e n t r a l to wing ba s e s ; wings h y a l i n e , t i n g e d w i t h amber, e s p e c i a l l y on h i n d wing and b a s a l h a l f of f o r e w i n g ; v e n a t i o n l i g h t y e l l o w i s h o r r e d d i s h brown; no margined c r o s s v e i n s ; c l a w s o f f o r e l e g s -64-o f male s i m i l a r ; abdominal t e r g i t e s 2-7 s e m i - h y a l i n e , p a l e p u r p l i s h t o l i g h t brown, a n t e r i o r margins c o l o u r l e s s , p o s t e r i o r margins n a r r o w l y d a r k e r , t e r g i t e s 8-10 opaque, y e l l o w i s h brown, t i n g e d w i t h p u r p l i s h or brown; s t e r n i t e s s i m i l a r to t e r g i t e s , but p a l e r ; no v e n t r a l m e d i a l m a r k i n g s ; penes d i v e r g e n t a l m o s t from base, each d i v i s i o n w i t h a s i n g l e w e l l - d e f i n e d l o b e a t apex; no v e n t r a l sub-a p i c a l s p i n e s , but each p e n i s w i t h a s i n g l e s p i n e on i n n e r m a r g i n . Mymph; Unknown D i s t r i b u t i o n : Utah, Wyoming, Montana, C a l i f o r n i a , B r i t i s h C o l u mbia. No specimens o f t h i s s p e c i e s were examined. CINYGlflULA PAR (EATON.) Cinygmula par ( E a t o n ) , S p i e t h , 1941, Ann. Ent. Soc. Amer., 34:89 fflayo, 1952, Pan. Pac. E n t . 28:182 ( B i b l i o g r a p h y ) A d u l t : A medium s i z e d l i g h t brown s p e c i e s ; c l a w s o f f o r e l e g of male d i s s i m i l a r ; wings h y a l i n e , may be f a i n t l y t i n g e d w i t h p a l e g r e y , d a r k e r a t base and a t s t i g m a , b r o w n i s h a t extreme base; v e n a t i o n y e l l o w i s h brown; no margined c r o s s v e i n s ; abdominal t e r g i t e s 2-7 s e m i - h y a l i n e , l i g h t brown w i t h p a l e d i r t y - w h i t i s h a n t e r i o r m a r g i n s , a n t e r o - l a t e r a l a r e a s , narrow median and submedian s t r e a k s ; s t r e a k s o u t l i n e d i n d a r k e r brown; t e r g i t e s 8-10 opaque brown; s t e r n i t e s p a l e r , g a n g l i o n i c markings on s t e r n i t e s 3-7 s e p i a - b r o w n ; penes each w i t h a l a r g e s p i n e on lower o u t e r m a rgins and a s m a l l e r s p i n e on i n n e r m a r g i n . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia No specimens o f t h i s s p e c i e s were examined. -65-CINYGMULA RAIYIALEYI (DODDS ) Cinyqmula r a m a l e y i (Dodds), Needham, 1935, The B i o l o g y o f M a y f l i e s , 390 ( B i b l i o g r a p h y ) A d u l t : A medium s i z e d r e d d i s h and p u r p l i s h brown s p e c i e s ; t h o r a x r e d d i s h brown, mesonotum y e l l o w i s h brown w i t h r e d d i s h brown m e d i a n s t r i p e and p u r p l i s h brown p o s t e r o - l a t e r a l a r e a s ; l a t e r a l a r e as of metanotum p u r p l i s h brown; claws o f f o r e l e g of male s i m i l a r ; wings h y a l i n e , amber t i n g e d t h r o u g h o u t ; v e n a t i o n f i n e , r e d d i s h brown; no margined c r o s s v e i n s ; abdominal t e r g i t e s 2-8 l i g h t red-brown, s e m i - h y a l i n e i n a n t e r i o r p o r t i o n s , r e s t p u r p l i s h brown; t e r g i t e 2 w i t h narrow h y a l i n e a n t e r i o r m a r g i n ; t e r g i t e 3 w i t h l / 3 of a n t e r i o r p o r t i o n h y a l i n e ; t e r g i t e s 4-7 w i t h a n t e r i o r l / 2 of a n t e r i o r p o r t i o n s h y a l i n e ; t e r g i t e s 8-10 opaque red-brown; p a l e submedian s t r e a k s o u t l i n e d i n d a r k e r c o l o u r on b a s a l t e r g i t e s ; s t e r n i t e s g r e y i s h , t i n g e d w i t h p a l e brown; p a l e red-brown g a n g l i o n i c m a r k i n g s on s t e r n i t e s 7-9 o n l y ; penes w i t h 2 l o b e s a t apex of each d i v i s i o n , the l a r g e r d i r e c t e d l a t e r a l l y ; a c u r v e d s p i n e s u b a p i c a l l y on i n n e r margin o n l y of each p e n i s . Nymph: Femora brown w i t h a p a l e L-shaped l o n g i t u d i n a l mark on b a s a l h a l f o f each; a p i c a l abdominal t e r g i t e s w h i t e . D i s t r i b u t i o n : Montana, B r i t i s h Columbia No specimens of t h i s s p e c i e s were examined. CINYGMULA UNIFQRMIS (McDUNNOUGH) Cinyqmula u n i f o r m i s (McDunnough), Needham, 1935, The B i o l o g y o f fflay-• f l i e s , 392 ( B i b l i o g r a p h y ) . -66-A d u l t : Wings h y a l i n e , u n i f o r m l y s u f f u s e d w i t h l i g h t amber; v e n a t i o n f i n e brown; no margined c r o s s v e i n s ; abdominal t e r g i t e s i n C. q a r t r e l l i b ut brown p o s t e r i o r margin n a r r o w e r , and a n t e r i o r h y a l i n e a r e a s w i d e r , and w i t h no r e d d i s h , t i n g e s ; a p i c a l t e r g i t e s opaque, a l m o s t s e p i a - b r o w n ; t e r g i t e 8 w i t h a narrow b l a c k i s h p o s t e r i o r m a r g i n ; s t e r n i t e s v e r y p a l e o c h r e o u s , 8 and 9 l i g h t y e l l o w - b r o w n ; g a n g l i o n i c m a r k i n g s f a i n t ruddy; each d i v i s i o n o f penes w i t h a w e l l - d e f i n e d a p i c a l l o b e , each b e a r i n g a s m a l l v e n t r a l s u b a p i c a l s p i n e on the i n n e r m a r g i n ; median s p i n e s not s e r r a t e on o u t e r m a r g i n s . Nymph; Femora o c h r e o u s , each w i t h 2 broad brown bands; a p i c a l a bdominal t e r g i t e s may be p a l e r than the o t h e r s , but each has a narrow dark a n t e r i o r m a r g i n . D i s t r i b u t i o n ; B r i t i s h Columbia No specimens o f t h i s s p e c i e s were examined. Cinyqmula s p . 1  A d u l t ; Unknown Nymph; A l l abdominal t e r g i t e s u n i c o l o u r e d . E c o l o g y ; Specimens of t h i s s p e c i e s were t a k e n from the m i d d l e arid edges of a number of l o c a t i o n s on the A l o u e t t e R i v e r . The r i v e r bed i n t h e s e l o c a t i o n s v a r i e d from mud, t h r o u g h sand, g r a v e l , and r o c k s , t o l a r g e b o u l d e r s . They were t a k e n a t a depth of 1 t o 3 f e e t , a l t h o u g f a t one l o c a t i o n , i n q u i e t w a t e r , they were taken from a depth o f 4 to 5 f e e t . The c u r r e n t v a r i e d from q u i e t t o r i p p l e s t o r a p i d s and f a l l s . The specimens were c o l l e c t e d d u r i n g the e n t i r e y e a r . -67-D i s t r i b u t i o n : B r i t i s h C olumbia M a t e r i a l Examined; 3 Nymphs, B r i t i s h C o l u m b i a ; A l o u e t t e R i v e r , VI.2.59 (N. F i l m e r ) 3 Nymphs, Loon C r . (H. L o r z ) . C inyqmula s p . 2 . A d u l t ; Unknown Nymph; I d e n t i c a l t o _C_^_ r a m a l e y i , but p a l e f e m o r a l m arkings d i s t i n c t l y V-shaped, r a t h e r than L-shaped. D i s t r i b u t i o n ; B r i t i s h Columbia M a t e r i a l Examined; 3 Nymphs, B r i t i s h C o l u m b i a : n r . Hell«s .Gate, VI.19.59 (G.G.E. S c u d d e r ) . GENUS EPEORUS EATON Epeorus E a t o n , E a t o n , 1881, E n t . IKlon. (flag., 18:26 ( B i b l i o g r a p h y ) A d u l t ; B a s a l j o i n t of f o r e t a r s u s of male e q u a l t o o r s l i g h t l y l o n g e r than the second j o i n t ; f o r e t a r s u s o f male l o n g e r than the t i b i a , o u t e r f o r k of the Rs of the h i n d wing p r e s e n t ; a p i c a l margin of f o r c e p s base not d e e p l y e x c a v a t e d ; male f o r c e p s 4 - j c i n t e d . Nymph: A f l a t t e n e d , s p r a w l i n g s p e c i e s ; m a x i l l a r y p a l p i 2 - j o i n t e d , 2nd j o i n t l e s s than 4 t i m e s the l e n g t h o f the g a l e a - l a c i n i a ; f i b r i l l a r p o r t i o n o f each p a i r of g i l l s p r e s e n t ; no f i n g e r l i k e p r o j e c t i o n of g i l l l a m e l l a e ; c l a w s not e l o n g a t e d ; 2 t a i l s . -68-SUBGENUS IRON EATON I r o n , Edmunds and A l l e n , 1957, Ann. E n t . Soc. Amer. 50 (4):319 Needham, 1935, The B i o l o g y o f m a y f l i e s , 392 ( B i b l i o g r a p h y ) A d u l t : Eyes of male l a r g e , u s u a l l y c o n t i g u o u s a p i c a l l y ; p o s t e r i o r m argin o f head of female v e r y s l i g h t l y e m a r g i n a t e ; p o s t e r i o r margin o f pronotum somewhat e x c a v a t e d m e d i a l l y ; f o r e l e g o f male as l o n g as o r s l i g h t l y l o n g e r t h a n the body; f o r e femur of male 2/3 as l o n g as the t i b i a , which i s 3/4 t h e l e n g t h o f the t a r s u s ; f o r e femur o f f e m a l e o n l y s l i g h t l y s h o r t e r than the t i b i a ; t a r s u s s u b e q u a l t o femur; i n h i n d l e g of b o t h s e x e s , femur about 3/4 the l e n g t h o f the t i b i a , t a r s u s about l / 2 as l o n g as femur; u s u a l l y a prominent b l a c k mark i n m i d d l e of femora, c l a w s u s u a l l y d i s s i m i l a r ; s t i g m a t i c c r o s s -v e i n s of f o r e w i n g not anastomosed; b a s a l c o s t a l c r o s s v e i n s o f t e n weak and i n d i s t i n c t ; second f o r k o f Rs of h i n d wing a r i s e s basad o f f i r s t f o r k ; second j o i n t of f o r c e p s l o n g e r than 3 r d and 4 t h j o i n t s combined; penes u s u a l l y u n i t e d i n the b a s a l 2/3; a p a i r of median s p i n e s on penes; a p i c a l margin of s u b a n a l p l a t e of female e m a r g i n a t e m e d i a l l y . Nymph: F r o n t a l and l a t e r a l m argins o f head expanded, c o m p l e t e l y c o v e r i n g the m o u t h p a r t s ; labrum s m a l l , 1-1/2 t o 2 tim e s as wide as l o n g , a n t e r o - l a t e r a l c o r n e r s rounded, a n t e r i o r margin w i t h s m a l l m e d i a l e x c a v a t i o n ; i n n e r c a n i n e l / 2 t o 3/4 as l o n g as t h e o u t e r one; l a c i n i a -a b s e n t or r e p r e s e n t e d by 2 t o 3 s h o r t h a i r s ; i n n e r a p i c a l margin of g a l e a - l a c i n i a each w i t h a t r i a d of s l i g h t l y i n c u r v e d s t o u t s p i n e s , each b e a r i n g a s l e n d e r t h r e a d - l i k e appendage a t i t s apex; may be 5-7 s l e n d e r s p i n e s a t the bases of these s p i n e s ; no s p i n e s a l o n g upper margins of m a x i l l a e ; median p o r t i o n o f hypopharynx l o n g e r and n a r r o wer than l a t e r a l p o r t i o n s ; g l o s s a e c o n i c a l , may be s l i g h t l y c o n v e r g e n t a p i c a l l y ; l a t e r a l m argins of pronotum s l i g h t l y d i l a t e d a t o r a n t e r i o r t o m i d d l e ; l e g j o i n t s ' T r i n g e d w i t h h a i r s ; f e m o r a l f l a n g e s harp p o i n t e d o r b l u n t ; c l a w s w i t h 3 t o 6 l a t e r a l a p i c a l p e c t i n a t i o n s ; abdominal t e r g i t e s w i t h a p a i r of s p i n e s a t each p o s t e r o l -a t e r a l a n g l e ; f i b r i l l a r p o r t i o n of each g i l l w e l l d e v e l o p e d , a p p a r e n t l y d o r s a l ; l a m e l l a t e p o r t i o n o f each g i l l n a r r o w l y t h i c k e n e d a l o n g o u t e r m a r g i n , which b e a r s many minute s p i n e s ; each g i l l o v e r l a p s the one b e h i n d i t , o u t e r margins p r e s s e d a g a i n s t the s u r f a c e ; a n t e r i o r l o b e o f f i r s t g i l l w e l l d e v e l o p e d , may or may not meet beneath t h e body; g i l l s o f l a s t segment u s u a l l y approach one a n o t h e r beneath body. Genotype: I r o n lonqimanus Eaton SUBGENUS IRONODES TRAVER I r o n o d e s , Edmunds and A l l e n , 1957, Ann. E n t . Soc. Amer. 50 ( 4 ) : 319 Needham, 1935, The B i o l o g y o f m a y f l i e s , 413 ( B i b l i o g r a p h y ) A d u l t : Eyes of male s m a l l t o moderate, u s u a l l y not c o n t i g u o u s a p i c a l l y ; p o s t e r i o r margin o f head of female d e e p l y e m a r g i n a t e ; f o r e l e g of male s l i g h t l y l o n g e r than body; femur 2/3 as l o n g as t h e t i b i a ; f o r e femur of female s l i g h t l y l o n g e r than t i b i a ; t a r s u s s u b e q u a l t o femur; i n h i n d l e g of b o t h s e x e s , t i b i a s l i g h t l y s h o r t e r than femur; male t a r s u s l / 2 t o 2/3 the l e n g t h of the t i b i a , f e m a l e t a r s u s l / 2 the l e n g t h o f the t i b i a ; c l a w s d i s s i m i l a r ; b a s a l c o s t a l c r o s s v e i n s -70-s t r o n g ; s t i g m a t i c c r o s s v e i n s numerous, s i m p l e , a s l a n t ; p o s t e r i o r b r a n c h of lYi i n f o r e w i n g forms a l m o s t a r i g h t a n g l e w i t h a n t e r i o r b r a n c h ; f o r k s o f Rs o f h i n d wing a r i s e a t about the same p o i n t ; media of h i n d wing f o r k e d about l / 3 from base; second j o i n t o f f o r c e p s l o n g e r than 3 r d and 4 t h combined, o f t e n more o r l e s s bowed near m i d d l e or i n a p i c a l t h i r d ; penes u s u a l l y s e p a r a t e d a l m o s t to base, somewhat compressed, e l o n g a t e , d i v e r g e n t a p i c a l l y ; a s e r i e s o f s m a l l s p i n e s on v e n t r a l s u r f a c e o f each d i v i s i o n ; a p i c a l margin o f s u b a n a l p l a t e o f female s l i g h t l y e m a r g i n a t e . Nymph: L a t e r a l and f r o n t a l margins of head expanded, c o m p l e t e l y c o v e r -i n g the m o u t h p a r t s ; f r o n t a l margin s l i g h t l y e m a r g i n a t e m e d i a l l y , d e n s e l y f r i n g e d w i t h h a i r s ; labrum 1-1/2 to 2 tim e s as wide as l o n g , f r o n t a l margin w i d e l y e x c a v a t e d m e d i a l l y ; a n t e r o - l a t e r a l a n g l e s s l i g h t l y rounded, l a t e r a l margins s l o p i n g toward base; i n n e r c a n i n e s 3/4 t o 7/8 as l o n g as the o u t e r ones; a few h a i r s i n l a c i n i a l r e g i o n ; upper margins o f ma n d i b l e s s l o p e s h a r p l y from bases o f c a n i n e s to molar s u r f a c e s ; a t h i c k e n e d a r e a below and s u b p a r a l l e l t o molar a r e a ; g a l e a - l a c i n i a w i t h a f r i n g e of l o n g h a i r s on o u t e r and upper m a r g i n s ; no t r i a d o f s t o u t s p i n e s a t t i p , but a few s l e n d e r s t r a i g h t s p i n e s ; second j o i n t of m a x i l l a r y p a l p i c l a v a t e , many s e r i e s o f s h o r t s p i n e s c u r v e d a t t i p s i n a p i c a l h a l f ; g l o s s a e s l i g h t l y concave i n i n n e r m a r g i n , s t r o n g l y convex on o u t e r , c l o s e t o g e t h e r and s l i g h t l y c o n v e r g e n t a p i c a l l y ; m e d i a l p o r t i o n o f hypopharynx much narrower and s h o r t e r than l a t e r a l p o r t i o n s ; f r o n t a l margin of pronotum e m a r g i n a t e , l a t e r a l m argins s l i g h t l y expanded, p o s t e r i o r margin w i t h a m e d i a l and 2 sub-m e d i a l e m a r g i n a t i o n s ; a t r a n s v e r s e r i d g e l / 3 d i s t a n c e from a n t e r i o r m argin of pronotum, d i v i d i n g pronotum i n t o a lower a n t e r i o r l / 3 and a h i g h e r p o s t e r i o r 2/3; each coxa w i t h two prominent f l a n g e - l i k e p r o j e c t i o n s ; f e m o r a l f l a n g e s s h o r t and b l u n t ; c l a w s w i t h p e c t i n a t i o n s near apex; g i l l - b e a r i n g abdominal segments o n l y w i t h v e r y s h o r t b l u n t p o s t e r o - l a t e r a l s p i n e s ; t e r g i t e s 1-9 w i t h a row of s u b m e d i a l s p i n e s , each a r i s i n g 1/3 from a n t e r i o r m a r g i n s ; f i b r i l l a r p o r t i o n o f g i l l s w e l l d e v e l o p e d , a p p a r e n t l y d o r s a l ; l a m e l l a t e p o r t i o n s s m a l l , o b o v a t e , f i r s t p a i r s m a l l e s t , s e v e n t h p a i r s l i g h t l y l a r g e r . Genotype: .Ironodes n i t i d u s ( i n I r o n ) Eaton SUBGENUS IRDNQPSIS TRAVER I r o n o p s i s , Edmunds and A l l e n , 1957, Ann. E n t . Soc. Amer. 50 (4) : 319 Needham, 1935, The B i o l o g y o f M a y f l i e s , 420 ( B i b l i o g r a p h y ) A d u l t ; L a r g e p u r p l i s h brown s p e c i e s ; eyes o f male l a r g e , c o n t i g u o u s a p i c a l l y ; p o s t e r i o r m a r g i n of head of female e m a r g i n a t e ; p o s t e r i o r margin o f pronotum d e e p l y e x c a v a t e d m e d i a l l y ; f o r e l e g o f male much l o n g e r than body; f o r e femur of male 3/4 as l o n g as t i b i a ; f o r e femur of female almost as l o n g as t i b i a ; a l l c l a w s d i s s i m i l a r ; s t i g m a t i c c r o s s v e i n s s t r o n g l y anastomosed; may be a l o n g i n t e r c a l a r y between C u l and f i r s t s e t of p a i r e d i n t e r c a l a r i e s ; f o r k s o f Rs of h i n d wing a r i s e a t about the same, p o i n t ; second j o i n t o f f o r c e p s not as l o n g as 3r d and 4 t h combined; penes r o d - l i k e , d i v e r g e n t a t t i p s ; a c l u s t e r o f s m a l l s p i n e s on v e n t r a l s u r f a c e s of each p e n i s some d i s t a n c e below apex; a p i c a l margin o f s u b a n a l p l a t e o f female w i t h a V-shaped median c l e f t . Nymph; F r o n t a l margin o f head and l a t e r a l m a r gins a n t e r i o r t o eyes expanded;, f r o n t a l margin v e r y s l i g h t l y e m a r g i n a t e . m e d i a l l y ; c a n i n e s -72-w i d e r and b l u n t e r than i n I r o n ; a row of h a i r s i n l a c i n i a l r e g i o n of each m a n d i b l e ; a t h i c k e n e d a r e a below and p a r a l l e l to molar a r e a o f each m a n d i b l e , and a n o t h e r below t h i s , on i n n e r m a r g i n , a t r i g h t a n g l e s t o molar a r e a ; g l o s s a e c o n i c a l , d i v e r g e n t a p i c a l l y , w i d e l y s e p a r a t e d a t base; a t r i a d o f s t o u t s p i n e s a t t i p of g a l e a -l a c i n i a ; labrurn d e f l e x e d , a n t e r o - l a t e r a l a n g l e s a n g u l a t e , not rounded, f r o n t a l margin not .emarginate; a n t e r o - l a t e r a l a n g l e s of pronotum rounded; femora, t i b i a e and t a r s i w i t h f r i n g e s of l o n g h a i r s , c l a w s w i t h t h r e e l a t e r a l p e c t i n a t i o n s near a p i c e s ; abdominal t e r g i t e s w i t h p o s t e r o - l a t e r a l e x p a n s i o n s s h o r t and b l u n t ; g i l l s o f 1 s t segment e n l a r g e d , a n t e r i o r l o b e s meeting beneath the body; i n t e r m e d i a t e g i l l s w e l l - d e v e l o p e d , t h i c k e n e d on o u t e r m a r g i n s , and o v e r l a p p i n g t h o s e b e h i n d them; s e v e n t h g i l l s meet beneath the body; f i b r i l l a r p o r t i o n of g i l l s s h o r t , not p r o m i n e n t , a p p a r e n t l y d o r s a l . Genotype; I r o n o p s i s q r a n d i s ( i n I r o n ) fflcDunnough EPEORUS Key To A d u l t s 1. B a s a l c o s t a l c r o s s v e i n s of f o r e w i n g weak. Eyes of male u s u a l l y c o n t i g u o u s 2. B a s a l c o s t a l c r o s s v e i n s of f o r e w i n g s t r o n g . Eyes of male not c o n t i g u o u s Ironodes T r a c e r 3 2. S t i g m a t i c c r o s s v e i n s s l a n t i n g . S t i g m a t i c c r o s s v e i n s of f o r e wing more or l e s s s t r o n g l y anastomosed, sometimes f o r m i n g 2 s e r i e s of c e l l u l e s I r o n o p s i s T r a v e r 4 S t i g m a t i c c r o s s v e i n s not s l a n t i n g . S t i g m a t i c c r o s s v e i n s of f o r e w i n g not anastomosed I r o n Eaton 5 3. w'ing membrane f a i n t l y a m b e r - t i n g e d , s t i g m a t i c a r e a smoky. -73-fflesonotum b l a c k - b r o w n f l a v i p e n n i s T r a v e r lYlesonotum l i g h t brown. S m a l l s p i n e s on v e n t r a l s u r f a c e o f penes r e l a t i v e l y few i n number • q r a n d i s (IYlcD) lYlesonotum b l a c k - b r o w n . S m a l l s p i n e s on v e n t r a l s u r f a c e of penes v e r y numerous permaqnus T r a v e r Abdominal t e r g i t e s 2-7 y e l l o w i s h , t e r g i t e s may be f a i n t l y smoky. T h o r a c i c p l e u r a e w i t h d i s t i n c t b l a c k i s h m a r k i n g s . G e n i t a l i a of a l b e r t a e type ( f i g . 3) d u l c i a n a IYlcD Abdominal t e r g i t e s 2-7 brown. No dark marks on p l e u r a e . G e n i t a l i a ' not of a l b e r t a e t y p e 6. V e n a t i o n dark brown. G e n i t a l i a of d e c e p t i v u s t y p e ( f i g . 3) d e c e p t i v u s (IYlcD) V e n a t i o n p a l e brown. G e n i t a l i a o f longimanus ( f i g . 3) o r of p l e u r a l i s t y p e ( f i g . 3) longimanus ( E a t o n ) Key To Nymphs T r i a d of s t o u t s p i n e s p r e s e n t a t t i p of g a l B a - l a c i n i a 2. No t r i a d of s p i n e s on g a l e a - l a c i n i a I r onodes Trav.e-r 3 A n t e r i o r margin of head e n t i r e . Median abdominal row of h a i r s p o o r l y d e v e l o p e d o r ab s e n t . A n t e r i o r p a i r o f g i l l s v a r i a b l e . G i l l s u s u a l l y t h i n and l i g h t , a n t e r i o r and o u t e r margins not n o t i c e a b l y d a r k e r . . . . . I r o n Ea„ton 4 A n t e r i o r margin o f head s l i g h t l y e m a r g i n a t e . Dense row of l o n g s e t a e on median l i n e o f abdominal t e r g i t e s . A n t e r i o r g i l l s meet beneath the body. G i l l s t h i c k and darkened, e s p e c i a l l y on the a n t e r i o r and o u t e r margins I r o n o p s i s T r a v e r 6 Body dark b l a c k i s h brown. A l l j o i n t s o f l e g s c o n c o l o u r o u s , no p o r t i o n darker, than the o t h e r s f l a v i p e n n i s T r a v e r A l l t e r g i t e s u n i c o l o u r e d brown. A p i c a l h a l f of t a r s i d a r k e r -74-t h an the r e s t of the l e g s . . . . . . . . . sp• 1 4. A n t e r i o r l o b e s of f i r s t g i l l s not g r e a t l y p r o l o n g e d , and so l a c k much of meeting beneath the the body, (flay or may not be a wedge-shaped p a l e mark on the median l i n e of the meso-notum. 5. A n t e r i o r l o b e s of f i r s t g i l l s meet beneath the body. No p a l e median l i n e on mesonotum .7. 5. liiedge-shaped p a l e mark on median l i n e of mesonotum p r e s e n t , w i d e s t near a n t e r i o r margin d e c e p t i v u s (McD) UJedge-shaped p a l e mark on median l i n e of mesonotum a b s e n t . . . s p . 5 6. Three l a t e r a l p e c t i n a t i o n s near apex o f each claw.. G i l l s on 7 t h segment meet beneath the body...... q r a n d i s (McD) No l a t e r a l p e c t i n a t i o n s near apex of each c l a w . G i l l s on 7th segment do not meet beneath the body permaqnus T r a v e r 7. A n t e r i o r margin of a l l s t e r n i t e s w i t h a dark t r a n s v e r s e s t r e a k on each s i d e of the median l i n e . Two dark s m a l l d o t s near m i d d l e of s t e r n i t e 9. Three t e e t h on claw lonqimanus ( E a t o n ) No dark s t r e a k s on s t e r n i t e s . No dark d o t s on s t e r n i t 9. Less than t h r e e t e e t h on the c l a w . . . . . .8. 8. Media], p r o j e c t i o n of a n t e r i o r l o b e of the f i r s t p a i r of g i l l s narrow and p o i n t e d . G i l l s s e p a r a t e d 9. M e d i a l p r o j e c t i o n of a n t e r i o r l o b e s of f i r s t p a i r of g i l l s b r o a d l y rounded. A l l g i l l s o v e r l a p p i n g t o form a l i g h t s u c t i o n d i s c sp. 2 9. Legs n o t banded. sp. 3 Legs banded sp. 4 -75-Unknown: I r o n d u l c i a n a McDunnough EPEORUS DECEPTIVUS (McDUNNOUGH) Epeorus deceptiv/us (McDunnough), Needham, 1935, The B i o l o g y of May-f l i e s , 399 ( I r o n ) ( B i b l i o g r a p h y ) A d u l t : A l i g h t brown s p e c i e s ; no markings on femora; f o r e l e g o f male much l o n g e r t h a n body; t i b i a s l i g h t l y more th a n 1-1/2 as l o n g as femur; wings h y a l i n e , v e n a t i o n f i n e , l i g h t brown; may be a f a i n t brown s t a i n i n s t i g m a t i c a r e a ; c o s t a l c r o s s v e i n s i n b a s a l a r e a i n d i s t i n c t ; abdominal t e r g i t e s 2-7 s e m i - h y a l i n e , 8-10 opaque; a n t e r i o r p o r t i o n s p a l e brown; p o s t e r i o r p o r t i o n s p u r p l i s h brown; p o s t e r i o r m argins and a n t e r i o r p r o j e c t i o n s from them d a r k e r p u r p l i s h brown; 8-10 may have opaque p i n k i s h w h i t e m a r k i n g s ; s t e r n i t e s p a l e r ; s m a l l o v a l brown g a n g l i o n i c m a r k i n g s ; penes may be widened s u b a p i c a l l y , l a t e r a l l o b e s p r o m i n e n t , or may be l o n g , s l e n d e r , f i n g e r - l i k e , l a t e r a l l o b e s f o l d e d f l a t and b a r e l y n o t i c e a b l e ; median s p i n e s l o n g , s l e n d e r and s l i g h t l y i n c u r v e d . Nymph: Wedge-shaped p a l e mark on median l i n e o f mesonotum, w i d e s t p o r t i o n near the a n t e r i o r margin; f l a n g e on femora 2 and 3 b l u n t a t t i p ; a n t e r i o r l o b e s o f 1 s t p a i r of g i l l s not g r e a t l y p r o l o n g e d or m e e t i n g beneath the body; o u t e r p o s t e r o - l a t e r a l s p i n e s on the m i d d l e abdominal t e r g i t e s s h o r t and b l u n t , n ot more than l / 4 as l o n g as the t e r g i t e , and about as l o n g as t h e i r w i d t h a t base. -76-D i s t r i b u t i o n ; B r i t i s h Columbia No specimens o f t h i s s p e c i e s were examined. EPEORUS DULCIANA (McDUNNOUGH ) Epeorus d u l c i a n a (lYlcDunnough), Needham, 1935, The B i o l o g y o f lYlay-f l i e s , 401 ( I r o n ) ( B i b l i o g r a p h y ) A d u l t ; Head y e l l o w i s h , r e d p a t c h e s on head, l a t e r a l a r e a s o f a n t e r i o r p o r t i o n of mesonotum; femora w i t h median b l a c k i s h s p o t s and narrow a p i c a l red-brown bands; f o r e femur s l i g h t l y s h o r t e r than t i b i a ; wings h y a l i n e ; v e n a t i o n y e l l o w i s h i n male, c r o s s v e i n s , e x c e p t i n s t i g m a t i c a r e a , i n d i s t i n c t ; humeral c r o s s v e i n s near s u b c o s t a b l a c k ; i n f e m a l e , v e n a t i o n f i n e , dark brown, c r o s s v e i n s d i s t i n c t ; a b dominal t e r g i t e s y e l l o w i s h to o l i v e brown, p o s t e r i o r margins n a r r o w l y b l a c k i s h ; s t e r n i t e s p a l e r . Nymph; Unknown D i s t r i b u t i o n : B r i t i s h Columbia No specimens o f t h i s s p e c i e s were examined. EPEORUS FLAUIPENNIS TRAVER Epeorus f l a v i p e n n i s T r a v e r , Needham, 1935, The B i o l o g y o f M a y f l i e s , 418 ( I r o n o d e s ) ( B i b l i o g r a p h y ) A d u l t : A dark brown s p e c i e s ; eyes l a r g e , a l m o s t c o n t i g u o u s a p i c a l l y ; head w i t h deep r e d m a r k i n g s ; a c o n s p i c u o u s creamy p a t c h c o n t a i n i n g a narrow r e d d i s h s t r e a k a n t e r i o r to base of f o r e w i n g ; a r e d s p o t above f o r e c o x a ; a s m a l l e r creamy p a t c h a n t e r i o r t o base of h i n d wing; -77-wings h y a l i n e , p a l e amber; v e n a t i o n dark brown except l o n g i t u d i n a l v e i n s of c o s t a l margin which are amber-brown; s t i g m a t i c a r e a smoky brown; i n f e m a l e , e n t i r e wing deep g r e e n i s h amber; abdominal t e r g i t e s 2-7 s e m i - h y a l i n e , dark brown w i t h a f a i n t red-brown t i n g e ; a n t e r i o r m argins p a l e r , p o s t e r i o r margins opaque dark brown; p l e u r a l f o l d n a r r o w l y dark brown; t e r g i t e s 8-10 opaque deeper brown; s t e r n i t e 9 b r i g h t red-brown. Mymph; D o r s a l l y b l a c k i s h brown; v e n t r a l l y y e l l o w i s h ; l e g s c o n c o l o u r o u s w i t h w h i t e marks b a s a l l y on femora; g i l l s p u r p l i s h b l a c k ; t r a c h e a e i n d i s t i n c t . D i s t r i b u t i o n : B r i t i s h C olumbia No specimens of t h i s s p e c i e s were examined. EPEORUS GRANDIS (McDUNNOUGH) Epeorus q r a n d i s (McDunnough), Needham, 1935, The B i o l o g y o f M a y f l i e s , 421 ( I r o n o p s i s ) ( B i b l i o g r a p h y ) A d u l t : A l i g h t brown s p e c i e s , w i t h a d a r k e r abdomen; two prominent b l a c k l i n e s i n a l i g h t . o l i v e brown p a t c h a n t e r i o r t o wing r o o t s , f o r e femora b l a c k i s h brown, p a l e r a t base, may be shaded w i t h o l i v e brown w i t h f a i n t b l a c k p e n c i l l i n g s ; wings h y a l i n e ; v e n a t i o n f i n e , d a r k ; s t i g m a t i c a r e a f a i n t l y b r o w n - t i n g e d ; humeral c r o s s v e i n f a i n t l y d a r k ; c r o s s v e i n s s t r o n g l y anastomosed; abdominal t e r g i t e s deep brown w i t h p a l e y e l l o w i s h l a t e r a l margins and p a l e y e l l o w i s h submedian s p o t s on p o s t e r i o r m a rgins o f segments 4 to 8, s m a l l e r on t e r g i t e 4; -78-t e r g i t e s 9 and 10 l a r g e l y y e l l o w i s h ; p a l e a r e a s may be o b s c u r e d by r e d d i s h s h a d i n g ; s t e r n i t e s p u r p l i s h brown, p a l e r p o s t e r i o r l y ; r e l a t i v e l y few s m a l l s p i n e s on v e n t r a l s u r f a c e s of each d i v i s i o n of penes. Nymph: Deep p u r p l i s h brown s p e c i e s ; l a t e r a l m argins of pronotum y e l l o w i s h f r i n g e o f l o n g h a i r s on femur, t i b i a and t a r s u s ; t h r e e l a t e r a l p e c t i n -a t i o n s near apex of each c l a w ; median a r e a s of t e r g i t e s 1 t o 4 and 8 t o 9 y e l l o w i s h ; s t e r n i t e mahogany brown m e d i a l l y , p a l e l a t e r a l l y , w i t h a s e r i e s of dark l a t e r a l marks a t the edges of the median dark a r e a s ; g i l l s o f 7 t h segment meet beneath the body. D i s t r i b u t i o n : B r i t i s h C o l u m b i a , A l b e r t a , C a l i f o r n i a , Montana No specimens of t h i s s p e c i e s were examined. EPEORUS LONGIMANUS (EATON) Epeorus lonoimanus ( E a t o n ) , S p i e t h , 1941, Ann. E n t . Soc. Amer. 34:88 ( I r o n ) ( B i b l i o g r a p h y ) A d u l t : A p a l e b r o w n i s h s p e c i e s ; femora w i t h a round b l a c k s p o t near m i d d l e ; wings h y a l i n e ; v e n a t i o n l i g h t b r o w n i s h amber; v e n a t i o n of h i n d wing p a l e r ; f o r e c l a w s d i s s i m i l a r ; abdominal t e r g i t e s 2-7 s e m i -h y a l i n e , p o s t e r i o r m a rgins and s h a d i n g a l o n g m i d - d o r s a l l i n e p u r p l i s h brown; the dark b o r d e r s do not e x t e n d t o the p o s t e r o - l a t e r a l a n g l e s , but an o b l i q u e b l a c k l i n e may e x t e n d from t h i s band o b l i q u e l y t o the p l e u r a l f o l d ; median l i n e n a r r o w l y p a l e , w i t h a d a r k e r s t r e a k on each s i d e ; p a l e submedian l u n a t e marks l i e on each s i d e w i t h i n the shaded a r e a s ; t e r g i t e s 8-10 opaque; s t e r n i t e s p a l e y e l l o w , nerve c o r d and g a n g l i a w h i t i s h and opaque, sometimes t r a c e s of p a l e o b l i q u e sub--79-median s t r e a k s on b a s a l and m i d d l e segments; each d i v i s i o n o f penes w i t h an e r e c t a p i c a l l o b e and a l a r g e r l a t e r a l l o b e , b e a r i n g a sharp l a t e r a l s p i n e ; penes bear a. median p a i r o f s t r o n g s p i n e s w i t h d i v e r g e n t t i p s . Nymph: • F l a n g e on femora 2 and 3 b l u n t a t t i p ; t h r e e t e e t h on c l a w s ; o u t e r p o s t e r o - l a t e r a l s p i n e s on m i d d l e abdominal segments s h o r t and b l u n t , not more than l / 4 as l o n g as the r e s p e c t i v e segments, and about as wide a t t h e i r b a s s s as l o n g ; a n t e r i o r margins of a l l s t e r n i t e s w i t h a.dark t r a n s v e r s e s t r e a k on each s i d e of the median l i n e ; 2 dark s m a l l s p o t s near the m i d d l e of s t e r n i t e 9.' D i s t r i b u t i o n : C o l o r a d o , Wyoming, Utah, Montana, A l b e r t a , B r i t i s h C o l u m bia. No specimens of t h i s s p e c i e s were examined. EPEORUS PERfflAGNUS (TRAVER) Epeorus permapnus ( T r a v e r ) , Needham, 1935, The B i o l o g y of M a y f l i e s , 423 ( I r o n o p s i s ) ( B i b l i o g r a p h y ) A d u l t : A dark brown s p e c i e s ; y e l l o w i s h a r e a c o n t a i n i n g a s i n g l e s h o r t b l a c k s t r e a k a n t e r i o r t o r o o t s of f o r e w i n g ; wings h y a l i n e ; l o n g i t u d i n a l v e i n s Sc, C and R t h i c k e n e d , dark r e d d i s h t o p u r p l i s h brown, e x c e p t bases o f Sc and R and base and a p i c a l t h i r d of C, which are y e l l o w i s h ; o t h e r l o n g i t u d i n a l v e i n s f i n e r , l i g h t red-brown; c r o s s v e i n s f i n e , y e l l o w i s h t o p a l e red-brown; humeral c r o s s v e i n p a l e ; abdominal t e r g i t e s y e l l o w i s h to o l i v e brown, w i t h b l a c k - b r o w n p a t c h e s ; . t e r g i t e s 2 and 3 w i t h 2 l a r g e p a t c h e s each, l e a v i n g p a l e l a t e r a l margins and median -89-l i n e ; t e r g i t e s 4 and 5 w i t h s m a l l e r p a t c h e s , l a t e r a l m argins i r r e g u l a r , median l i n e o b s c u r e d ; t e r g i t e s 6-8 w i t h dark median t r i a n g l e s , apex p o i n t i n g p o s t e r i o r l y , e x t e n d i n g 3/4 the l e n g t h of each t e r g i t e , w i t h a dark s p o t i n each p a l e l a t e r a l a r e a ; t e r g i t e s 9- and 10 r e d d i s h brown, a n t e r i o r margins n a r r o w l y b l a c k ; l a t e r a l b l a c k s p o t s on 9, a b l a c k median l i n e and median p o s t e r i o r margin on 10; s t e r n i t e s o l i v e brown, b a s a l s t e r n i t e s and s t e r n i t e 8 shaded w i t h r e d brown; s t e r n i t e 9 deeper brown, i n t e r m e d i a t e s t e r n i t e s each w i t h a round smoky s p o t near a n t e r o - l a t e r a l a n g l e s , s p o t s i n each s t e r n i t e c o n n e c t e d by a smoky t r a n s v e r s e band; penes w i t h numerous s m a l l s p i n e s on v e n t r a l s u r f a c e of each d i v i s i o n . Nymph: No l a t e r a l p e c t i n a t i o n s near apex of each c l a w ; g i l l s o f 7 t h segment do not meet beneath the body. E c o l o g y : Specimens o f t h i s s p e c i e s were t a k e n from t h e m i d d l e and edge o f a number o f l o c a t i o n s on the A l o u e t t e R i v e r . The stream bed v a r i e d from mud, t h r o u g h sand, g r a v e l and l a r g e and s m a l l r o c k s , to b o u l d e r s . The depth of the r i v e r i n t h e s e l o c a t i o n s v a r i e d from 1 to 3 f e e t , and t h e c u r r e n t was i n most c a s e s a moderate r i p p l e , a l t h o u g h specimens were a l s o found i n r a p i d s and under f a l l s , and i n q u i e t w a t e r . The specimens c o l l e c t e d i n t h i s l a t t e r l o c a t i o n may have been washed t h e r e by the s w i f t e r water i n the m i d d l e o f the r i v e r . The specimens were c o l l e c t e d d u r i n g the e n t i r e y e a r . D i s t r i b u t i o n : Oregon, B r i t i s h Columbia - 8 1 -f f l a t e r i a l Examined: 2 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) VI.2.59 (N. F i l m e r ) ; 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) V.26.59 (N. F i l m e r ) . Epeorus s p. 1 A d u l t : Unknown Nymph: A p i c a l h a l f o f t a r s i d a r k e r than the r e s t o f the l e g s ; t e r g i t e s u n i c o l o u r e d brown, no t r a c h e a t i o n on g i l l s ; g e n e r a l d e s c r i p t i o n as f o r subgenus I r o n o d e s . D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: 3 Nymphs, B r i t i s h C o l u mbia: Loon Creek ( C l i n t o n ) , VI.16.56 (H. L o r z ) ; 8 Nymphs, B r i t i s h C o l u m b i a : n r . H e l l ' s Gate, VI.19.59 (G.G.E. S c u d d e r ) . Epeorus sp. 2  A d u l t : Unknown Nymph: F r i n g e on a n t e r i o r margin of the froms; no p a l e median l i n e on mesonotum; l e s s than 3 t e e t h on each c l a w ; no dark s t r e a k s o r d o t s on the abdominal s t e r n i t i s ; a n t e r i o r l o b e s of f i r s t p a i r o f g i l l s b r o a d l y rounded and meet beneath the body; a l l g i l l s o v e r l a p the f o l l o w i n g p a i r ; and l a s t p a i r meet beneath the body to form a s t r o n g s u c t i o n d i s c ; o t h e r taxonomic c h a r a c t e r i s t i c s as f o r the subgenus I r o n . -82-E c o l o q y : Nymphs of t h i s s p e c i e s were t a k e n from the m i d d l e and edges of 5 l o c a t i o n s on t h e A l o u e t t e R i v e r , always from a depth o f one t o two f e e t . The s u b s t r a t e c o n s i s t e d of g r a v e l , r o c k s , b o u l d e r s , and b e d r o c k . In a l l c a s e s e x c e p t one, the c u r r e n t was v e r y r a p i d . The e x c e p t i o n was a q u i e t g r a v e l - l i n e d p o o l , i n t o which the nymphs had no doubt been washed by the t u r b u l e n c e of the c u r r e n t . A l l nymphs were c o l l e c t e d d u r i n g 3une, August, and November. D i s t r i b u t i o n : B r i t i s h C olumbia M a t e r i a l Examined: 3 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) VI.2.59 ( N . J . F i l m e r ) ; 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) V I I I . 1 8 . 5 9 (N.3. F i l m e r ) ; 1 Nymph, B r i t i s h C o l u m b i a : Loon Creek ( C l i n t o n ) , VI.16.59 (H. L o r z ) ; 5 Nymphs, B r i t i s h C o l u m b i a : n r . H e l l ' s Gate, VI.19.59 (G.G.E. S c u d d e r ) ; 8 Nymphs, B r i t i s h C o l u m b i a : Smith F a l l s H a t c h e r y Creek, C u l t u s Lake, VI.12.? (H. L o r z ) . Epeorus sp. 3  A d u l t : Unknown Nymph: Legs not banded a l t e r n a t e l y l i g h t and d a r k ; l e s s t h a n 3 t e e t h on each c l a w ; no p a l e l i n e on mesonotum; g i l l s l a m e l l a t e , s e p a r a t e d , not f o r m i n g a s u c t i o n d i s c ; a n t e r i o r l o b e of 1 s t p a i r of g i l l s narrow and p o i n t e d , meet beneath the body; abdominal s t e r n i t e s w i t h no dark s t r e a k s or. d o t s ; g e n e r a l d e s c r i p t i o n as f o r subgenus I r o n . -83-E c o l o q y t Nymphs o f t h i s s p e c i e s were c o l l e c t e d from the m i d d l e and edges o f a number of l o c a t i o n s on the A l o u e t t e R i v e r . G e n e r a l l y they were t a k e n a t depth of one t o two f e e t , a l t h o u g h they were a l s o t a k e n a t depths o f two i n c h e s and f i v e f e e t . The stream bed i n c l u d e d mud, s i l t , s and, g r a v e l , r o c k s , b o u l d e r s , and b e d r o c k . The c u r r e n t was u s u a l l y r a p i d o r r i p p l y ; a l t h o u g h i n two c a s e s the water was q u i e t and s l o w . They were t a k e n the year round. D i s t r i b u t i o n : B r i t i s h Columbia f f l a t e r i a l Examined; 2 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) • • VI.2.59 (N.3. F i l m e r ) Epeorus sp. 4  A d u l t : Unknown Nymph: Uecy s i m i l a r t o Epeorus s p . 3 but l e g s banded a l t e r n a t e l y l i g h t and d a r k ; g i l l s v e r y l a r g e ; p o s t e r o - l a t e r a l a n g l e s o f the abdominal t e r g i t e s bear two sharp s p i n e s each. E c o l o g y : T h i s s p e c i e s was ta k e n from the m i d d l e of 3 l o c a t i o n s on the A l o u e t t e R i v e r , a l l a t a depth of one t o two f e e t . The s u b s t r a t e c o n s i s t e d of g r a v e l , r o c k s , b o u l d e r s , and bedr o c k . In a l l c a s e s the c u r r e n t was r a p i d . A l l specimens were c o l l e c t e d i n August. D i s t r i b u t i o n : B r i t i s h Columbia -84-ITIaterial Examined: 2 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.), V I I I . 2 6 . 5 9 ( N . J . F i l m e r ) . Epeorus sp. 5  A d u l t : Unknown Nymph: Very s i m i l a r to E. deceptiv/us, but l a c k i n g the wedge-shaped p a l e mark on t h e mesonotum. D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: 3 Nymphs, B r i t i s h C o l u m b i a : n r . H e l l ' s Gate, VI.19.59, (G.G.E. Scud d e r ) GENUS HEPTAGENIA WALSH H e p t a q e n i a , Needham, 1935, The B i o l o g y o f M a y f l i e s , 335 ( B i b l i o g r a p h y ) A d u l t : Eyes o f male u s u a l l y l a r g e , not c o n t i g u o u s a p i c a l l y , pronotum d e e p l y e x c a v a t e d on p o s t e r i o r margin m e d i a l l y ; f o r e l e g of male l o n g e r than body;of f e m a l e , about 3/4 the l e n g t h of the body; f o r e femur of male s u b e q u a l t o or s l i g h t l y s h o r t e r than the t i b i a ; t a r s u s about 1-1/4 t i m e s the l e n g t h o f the t i b i a ; b a s a l j o i n t o f f o r e t a r s u s of male l / 6 to l / 3 as l o n g as the second j o i n t ; f o r e femur of female s u b e q u a l t o t i b i a ; t a r s u s about 3/4 the l e n g t h o f t h e t i b i a ; b a s a l t a r s a l j o i n t about l / 2 the l e n g t h of t h e second j o i n t ; i n h i n d l e g of both s e x e s , t i b i a about 3/4 the l e n g t h o f the femur; t a r s u s s l i g h t l y more th a n l / 2 the l e n g t h o f the t i b i a ; a l l c l a w s d i s s i m i l a r ; t y p i c a l H e ptagenine wing v e n a t i o n ; s t i g m a t i c c r o s s v e i n s not anastomosed or s l a n t e d , Of o f Rs of h i n d wing p r e s e n t ; a p i c a l margin of f o r c e p s -85-base o f male u s u a l l y s l i g h t l y e m a r g i nate m e d i a l l y , may be d e e p l y e m a r g i n a t e , o r convex; f o r c e p s 4 - j o i n t e d ; penes u s u a l l y u n i t e d i n b a s a l h a l f of t u j o - t h i r d s , not d i s t i n c t l y L-shaped, d i s t a l p o r t i o n s d i v e r g e n t a p i c a l l y ; u s u a l l y each d i v i s i o n w i t h an a p i c a l l o b e and a l a t e r a l l o b e - l i k e e x t e n s i o n o f t e n b e a r i n g a prominent m a r g i n a l s p i n e ; a p a i r o f s t o u t s p i n e s between d i v i s i o n s ; one t o t h r e e p a i r s of s l e n d e r s p i n e s may be on or near the i n n e r m a r g i n o f each d i v i s i o n , near apex; s u b a n a l p l a t e of female w e l l d e v e l o p e d , o b t u s e l y o r r e t u s e l y rounded i n i t s a p i c a l m a r g i n . Nymph: Head d e p r e s s e d , o f t e n l a r g e f o r body; f r o n t e n t i r e o r v e r y s l i g h t l y e m a r g i n a t e ; labrum more than f o u r t i m e s as wide as l o n g , e x t e n d i n g 2/3 t o 3/4 the d i s t a n c e a l o n g the a n t e r i o r margin of the head; no c h i t i n i z e d a r e a s on m a n d i b l e s ; i n n e r c a n i n e o f r i g h t m a n d ible at l e a s t 3/4 as l o n g as the o u t e r ; c a n i n e s s u b e q u a l on l e f t m a n d i b l e : 2 o r 3 b l u n t t e e t h a t t i p of each o u t e r c a n i n e ; l a c i n i a o f r i g h t m a n d ible may be r e p r e s e n t e d by a row of l o n g h a i r s , o f the l e f t by a l a r g e s l e n d e r s p i n e , or on bo t h m a n d i b l e s by 2 o r 3 l o n g s l e n d e r s p i n e s ; p e c t i n a t e s p i n e s on crown of g a l e a - l a c i n i a ; m a x i l l a r y p a l p i 2-segmented, second j o i n t s h o r t e r t h a n 4 t i m e s the l e n g t h o f the g a l e a - l a c i n i a and not v i s i b l e d o r s a l l y ; . p a l p i s l e n d e r , many l o n g h a i r s near t i p of d i s t a l j o i n t ; g l o s s a e of labrum s t r o n g l y a r c h e d away from each o t h e r , may converge a t t i p s ; . l a t e r a l s p i n e s of abdominal t e r g i t e s v a r i a b l e ; f i l a m e n t o u s p o r t i o n o f g i l l s w e l l d e v e l o p e d , d i r e c t e d v e n t r a l l y ; l a m e l l a t e p o r t i o n s d i r e c t e d l a t e r a l l y , not c o n v e r i n g beneath the body; 1 s t and 7 t h g i l l s s m a l l e r t h a n i n t e r m e d i a t e g i l l s , -86-7 t h l a r g e r than the 1 s t ; f i b r i l l a r p o r t i o n may be w a n t i n g on segment 7; no f i n g e r l i k e p r o j e c t i o n s on g i l l l a m e l l a e ; 3 t a i l s , e q u a l i n l e n g t h . Genotype; H e p t a q e n i a f l a v e s c e n s Walsh HEPTAGENIA  Key To A d u l t s 1. ' Abdominal t e r g i t e s p a l e 2. Abdominal t e r g i t e s p a t t e r n e d w i t h brown or p u r p l i s h - b r o w n 3. 2. Abdominal t e r g i t e s p a l e creamy to y e l l o w i s h w h i t e , 2-6 semi-h y a l i n e , 7-10 opaque, the l a t t e r more d i s t i n c t l y h y a l i n e . W i t h i n the dark band on each s t e r n i t e are two p a l e d o t s , one on each s i d e of the median l i n e near c e n t e r o f each s t e r n i t e , and two p a l e o b l i q u e median dashes from a n t e r i o r m a r g i n . V e i n s p a l e . G e n i t a l i a of s i m p l i c o i d e s t y p e ( f i g . 3 ) . s i m p l i c o i d e s IYlcD Abdominal segments p a l e , 2-7 s e m i - h y a l i n e , 8-10 opaque. P o s t e r i o r margins o f t e r g i t e s 2-7 smoky grey o r b r o w n i s h , t e r g i t e s 8-10 t i n g e d w i t h p i n k . S t e r n i t e s p a l e y e l l o w i s h . V e i n s b l a c k . G e n i t a l i a o f e l e g a n t u l a type ( f i g . 3) e l e q a n t u l a ( E a t o n ) 3. T h o r a c i c notum brown, w i t h a deeper brown m i d - d o r s a l s t r i p e , most e v i d e n t on a n t e r i o r p o r t i o n of mesonotum. Abdominal t e r g i t e s v e r y p a l e b r o w n i s h , 2-7 w i t h a dark p u r p l i s h - b r o w n median s t r i p e e n c l o s i n g a p a l e narrow m i d - d o r s a l l i n e , on p o s t e r i o r margins a narrow dark band of the same c o l o u r , w i t h submedian broad dark bands p r o j e c t i n g f o r w a r d from i t , but not a t t a i n i n g the a n t e r i o r m a r g i n . The dark d o r s a l and submedian s t r i p e s may c o a l e s c e t o form a s i m p l e dark -87-s h a d i n g , or w i t h p a l e r l u n a t e marks s u b m e d i a l l y from the a n t e r i o r m a r g i n . T e r g i t e s 8-10 opaque, l i g h t r e d d i s h brown. S t e r n i t e s p a l e . . s o l i t a r i a fflcD Not as above 4. T h o r a c i c notum l i g h t brown, w i t h two p u r p l i s h p a t c h e s on the p l e u r a a n t e r i o r to m e s o t h o r a c i c wing b a s e s . T e r g i t e s p a l e brown w i t h a p u r p l i s h t i n g e , 7-10 dark p u r p l i s h - b r o w n . S t e r n i t e s p i n k i s h . . . sp. Not as above.... 5 T h o r a c i c notum brown. A l l t e r g i t e s brown w i t h a p a l e a r e a on l a t e r a l p o s t e r i o r b o r d e r s . S t e r n i t e s p a l e , w i t h d a r k e r g a n g l i o n i c m a r k i n g s ..sp. 2 Not as above 6 T h o r a c i c notum brown.. T e r g i t e s brown w i t h a t h i n p a l e median l i n e , f l a n k e d by two p a l e submedian d o t s . S t e r n i t e s p a l e .sp. 3 T h o r a c i c notum dark brown. T e r g i t e s v e r y dark brown, w i t h no p a l e m a r k i n g s . . P a l e spot on m i d l i n e o f mesonotum. s p . 4 Key To Nymphs Pronotum w i d e s t a t a n t e r i o r m a r g i n . F i l a m e n t o u s p o r t i o n o f 7 t h p a i r o f g i l l s p r e s e n t . Claws l a c k i n g p e c t i n a t i o n s . No abdominal s p i n e s on segment 8 3. Pronotum w i d e s t a t or near the m i d d l e . F i l a m e n t o u s p o r t i o n of 7th p a i r of g i l l s w a n t i n g . Claws w i t h or w i t h o u t p e c t -i n a t i o n s . Segment 8 w i t h or w i t h o u t abdominal s p i n e s . . . . . . 2 . 2. Claws w i t h p e c t i n a t i o n s . Abdominal s p i n e s on Segment 8. T e r g i t e s 8-10 l a r g e l y dark.' s i m p l i c o i d e s IYlcD Claws w i t h o u t p e c t i n a t i o n s . No abdominal s p i n e s on segment 8. T e r g i t e 8 l a r g e l y p a l e sp.4 3. P a l e submedian s t r e a k s c o a l e s c e on t e r g i t e s 8 and 9 t o form a l a r g e p a l e b l o t c h on each e l e q a n t u l a ( E a t o n ) No p a l e submedian s t r e a k s .4. 4. T e r g i t e s 8-10 or 9-10 c o m p l e t e l y p a l e . No p a l e s p o t s on head. F r o n t a l p l a t e does not e x t e n d beyond eyes s p . 5 T e r g i t e s 8 and 9 w i t h p a l e b l o t c h e s o r c o m p l e t e l y d a r k . P a l e s p o t s on head. F r o n t a l p l a t e extends beyond the a n t e r i o r h a l f o f the l a t e r a l edges of the e y e s . . . . . 5. 5. T e r g i t e s 8 and 9 w i t h p a l e b l o t c h e s o r c o m p l e t e l y d a r k . L a r g e p a l e spot.between the bases of the antennae and a n t e r i o r m a r g i n of the head sp. 6 T e r g i t e s 8 and 9 dark. Four p a l e s p o t s on the a n t e r i o r and l a t e r a l margins of the f r o n t a l p l a t e s p . 7 Unknown; H e p t a q e n i a s o l i t a r i a IYlcD HEPTAGENIA ELEGANTULA (EATON) H e p t a q e n i a e l e q a n t u l a ( E a t o n ) , Needham, 1935, The B i o l o g y o f Way-f l i e s , 345 ( B i b l i o g r a p h y ) A d u l t ; A y e l l o w i s h s p e c i e s ; t h o r a c i c notum p a l e y e l l o w i s h ; a median r e d d i s h brown s t r i p e on mesonotum; a b l a c k s t r e a k above m i d d l e and h i n d coxae and a b l a c k dot p o s t e r i o r to h i n d coxae; wings h y a l i n e ; -89-c o s t a l margin of f o r e w i n g may be t i n g e d w i t h p a l e lemon y e l l o w , w i t h g r e e n i s h or b i s t r e - g r e y ; v e n a t i o n f i n e , b l a c k , e x c e p t f o r y e l l o w amber b a s a l h a l v e s of Sc and R; humeral c r o s s v e i n and c o s t a l c r o s s -v e i n s t h i c k e r ; a w e l l marked b l a c k . b u l l a ; abdominal t e r g i t e s p a l e ; t e r g i t e s 2-7 s e m i - h y a l i n e w i t h smoky grey or b r o w n i s h p o s t e r i o r m a r g i n s ; t e r g i t e s 8-10 opaque, t i n g e d w i t h p i n k ; s t e r n i t e s p a l e y e l l o w i s h ; g e n i t a l i a of e l e g a n t u l a t y p e . Nymph; Pronotum w i d e s t a t the a n t e r i o r m a r g i n ; pronotum w i t h a wide p a l e median s t r e a k and p a l e l a t e r a l a r e a s ; c l a w s l a c k i n g p e c t i n -a t i o n s ; no o b l i q u e dark l i n e s on abdominal t e r g i t e s ; p a l e submedian s t r e a k s on t e r g i t e s 8 and 9 c o a e l e s c e t o form a l a r g e p a l e b l o t c h on each; no p o s t e r o - l a t e r a l s p i n e s on t e r g i t e s 6 to 8; f i l a m e n t o u s p o r t i o n of 7 t h p a i r of g i l l s p r e s e n t . D i s t r i b u t i o n : C o l o r a d o , Nebraska, Kansas, Montana, Utah, B r i t i s h C o l u m b i a . No specimens of t h i s s p e c i e s were examined. HEPTAGENIA 5IMPLIC0IDES fflcDUNNQUGH H e p t a q e n i a s i m p l i c o i d e s McDunnough, Needham, 1935, The B i o l o g y of M a y f l i e s , 361 ( B i b l i o g r a p h y ) A d u l t : A p a l e y e l l o w i s h s p e c i e s ; . t h o r a x p a l e creamy to y e l l o w i s h w h i t e ; wings h y a l i n e ; v e n a t i o n p a l e ; b a s a l c o s t a l c r o s s v e i n s few i n number, a l m o s t i n v i s i b l e ; abdominal t e r g i t e s creamy w h i t e t o p a l e y e l l o w i s h , 2-6 s e m i - h y a l i n e , 7-10 opaque, w i t h no s e m i - t r a n s l u c e n t p a t c h e s o r -90-dark m a r k i n g s ; t r a c h e a e on t e r g i t e s o u t l i n e d i n p a l e g r e y ; g e n i t a l i a o f s i m p l i c o i d e s t y p e ; median s p i n e s on penes not l o n g , v e r y s l i g h t l y t w i s t e d a t base o n l y , no l a t e r a l s p i n e s near m a r g i n . Nymph: Head of normal s i g e , w i d t h no more t h a n pronotum, and head and t h o r a x t o g e t h e r no more than 3/4 as l o n g as the abdomen; no dark s p o t s on f r o n t a l margin of head; pronotum w i d e s t a t or near the m i d d l e ; femora l a r g e l y brown, w i t h p a l e b a s a l and d i s t a l s p o t s and a p a l e median g i g z a g band; t a r s u s w h o l l y dark brown; c l a w s w i t h p e c t i n a t i o n s ; abdominal t e r g i t e s w i t h p a l e submedian m a r k i n g s o b s c u r e d ; t e r g i t e s 8-10 l a r g e l y dark; s p i n e s on p o s t e r o - l a t e r a l . a n g l e s of t e r g i t e 8, and perhaps a l s o on 6 and 7; f i l a m e n t o u s p o r t i o n of 7 t h p a i r of g i l l s w a n t i n g . D i s t r i b u t i o n ; A l b e r t a , Washington, B r i t i s h Columbia No specimens of t h i s s p e c i e s were examined. HEPTAGENIA SOLITARIA fflcDUNNQUGH  H e p t a q e n i a s o l i t a r i a fflcDunnough, Needham, 1935, The B i o l o g y of fflayflies, 361 ( B i b l i o g r a p h y ) A d u l t : A brown s p e c i e s ; t h o r a c i c notum brown w i t h a deeper brown m i d d o r s a l s t r i p e , p a r t i c u l a r l y e v i d e n t on mesonotum; s h o r t b l a c k s t r e a k s j u s t above bases of m i d d l e and h i n d coxae, and above t h e s e , o t h e r b l a c k s t r e a k s i n l i n e w i t h wing r o o t s ; t h e s e s t r e a k s may be o b s c u r e d ; wings h y a l i n e ; v e n a t i o n f i n e brown, e x c e p t f o r b a s a l h a l v e s of Sc and R which a r e . t h i c k e n e d and p a l e y e l l o w i s h ; c o s t a l margin t i n g e d w i t h p a l e lemon y e l l o w ; c r o s s v e i n s t h i c k e r than l o n g i t u d i n a l s ; abdominal - 9 1 -t e r g i t e s v e r y p a l e b r o w n i s h ; t e r g i t e s 2-7 w i t h a broad dark p u r p l i s h brown median s t r i p e e n c l o s i n g a narrow p a l e m i d - d o r s a l l i n e ; p o s t e r i o r margin dark p u r p l i s h brown w i t h broad submedian bands e x t e n d i n g f o r w a r d from t h i s , but not a t t a i n i n g the a n t e r i o r m a r g i n ; t h e s e m a r k i n g s may be o b s c u r e d and form a dark s h a d i n g , or the p a l e submedian markings from a n t e r i o r margin may be l u n a t e ; t e r g i t e s 8-10 opaque, l i g h t r e d d i s h brown; s t e r n i t e s p a l e r , no ruddy t i n g e ; g e n i t a l i a o f p u l l a t y p e ( f i g . 3 ) ; upper p a i r of median s p i n e s s m a l l e r than lower ones. Nymph; Unknown D i s t r i b u t i o n : Montana, C o l o r a d o , B r i t i s h C olumbia No specimens o f t h i s s p e c i e s were examined. H e p t a q e n i a s p. 1  A d u l t ; Thorax l i g h t brown; a p u r p l i s h p a t c h a n t e r i o r to each m e s o t h o r a c i c wing base; f o r e l e g s l i g h t brown; o t h e r l e g s y e l l o w ; abdominal t e r g i t e s p a l e brown w i t h a p u r p l i s h t i n g e ; t e r g i t e s 7-10 dark p u r p l i s h brown, s t e r n i t e p i n k i s h ; t a i l s y e l l o w ; g e n i t a l i a w i t h penes e l o n g a t e , t u b e l i k e , each w i t h two l a t e r a l s h arp s h o r t s p i n e s from base of second d i v i s i o n . Nymph: Unknown D i s t r i b u t i o n ; B r i t i s h Columbia M a t e r i a l Examined; 1 Female, B r i t i s h C o l u m b i a : Q u e s n e l , V I I I . 2 . 4 8 (G.3. S p e n c e r ) 1 Female, B r i t i s h C o l u m b i a : Q u e s n e l , V I I I . 1 3 . 4 8 (G.3. Spencer 2 M a l e s , B r i t i s h C o l u m b i a : Cowichan Lake, VI.12.35 ( J . L . McHugh) 1 ?, B r i t i s h C o l u m b i a : Nanaimo, VI.11.35 ( 3 . L . McHugh) -92-H e p t a q e n i a sp, 2  A d u l t : Very s i m i l a r t o H e p t a q e n i a s p . 1; t h o r a x and abdominal t e r g i t e s brown, l a c k i n g the p u r p l i s h t i n g e ; p a l e a r e a on p o s t e r o - l a t e r a l a n g l e s o f t e r g i t e s ; s t e r n i t e s p a l e , w i t h dark g a n g l i o n i c m a r k i n g s ; a l l l e g s and t a i l s p a l e ; 2nd c u b i t a l i n t e r c a l a r y bends f o r w a r d b a s a l l y toward 1 s t c u b i t a l i n t e r c a l a r y ; s h o r t s p i n e s on penes w a n t i n g . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia m a t e r i a l Examined: 1 Wale, B r i t i s h C o l u m b i a : Q u e s n e l , V I I I . 3 . 4 8 , ( G . J . S p e n c e r ) 1 Male, B r i t i s h C o l u m b i a : L y t t o n , V I I I . 2 3 . 3 1 ( G . J . S p e n c e r ) 3 t e n e r a l a d u l t s t a k e n a t L y t t o n , B r i t i s h Columbia on VII.12.31 and one on V I I I . 2 3 . 3 1 , by G.J. Spencer a r e p r o b a b l y o f t h i s s p e c i e s . H e p t a q e n i a s p. 3  A d u l t : ( F e m a l e ) Very s i m i l a r to H e p t a q e n i a sp. 2, but p a l e m a r k i n g s on the abdominal t e r g i t e s c o n s i s t o f a t h i n median l i n e . f l a n k e d on each t e r g i t e by 2 l i g h t d o t s ; no g a n g l i o n i c m a r k i n g s ; c r o s s v e i n s on wings more numerous. Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia m a t e r i a l Examined: 1 Female, B r i t i s h C o l u m b i a : A u s t r a l i a n , V I I I . 1 5 . 4 8 ( G . J . Spencer) -93-H e p t a q e n i a sp. 4  A d u l t : (fflale) S i m i l a r t o H e p t a q e n i a sp. 3, but no p a l e a r e a s on t e r g i t e s ; a v e r y dark brown s p e c i e s ; p a l e s p o t on m i d l i n e of mesonotum. Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia m a t e r i a l Examired: 1 Fflale, B r i t i s h C o l u m b i a : C h i l c o t i n , IX.22.62 (G.G.E. Scudder) H e p t a q e n i a sp. 5  A d u l t : Unknown Nymph: F r o n t a l p l a t e does not extend beyond the eyes; no p a l e s p o t s on head; pronotum w i d e s t a t a n t e r i o r m a r g i n ; c l a w s l a c k i n g i n p e c t -i n a t i o n s ; abdominal t e r g i t e s w i t h no p a l e submedian s t r e a k s ; t e r g i t e s 8-10 or 9-10 c o m p l e t e l y p a l e ; f i l a m e n t o u s p o r t i o n o f 7 t h p a i r of g i l l s p r e s e n t ; no abdominal s p i n e s on t e r g i t e 8. D i s t r i b u t i o n : B r i t i s h Columbia m a t e r i a l Examined -: 2 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) 11.15.60 . (N.O. F i l m e r ) H e p t a q e n i a sp. 6  A d u l t : Unknown Nymph: F r o n t a l p l a t e of head e x t e n d s beyond the a n t e r i o r h a l f o f the l a t e r a l edges of the eyes; l a r g e p a l e s p o t between the bases o f the antennae and the a n t e r i o r margin of the head; pronotum w i d e s t a t the -94-a n t e r i o r m a r g i n ; c l a w s l a c k i n g i n p e c t i n a t i o n s ; abdominal t e r g i t e s w i t h no p a l e submedian s t r e a k s ; t e r g i t e s 8 and 9 may have p a l e b l o t c h e s , o r may be c o m p l e t e l y dark; no abdominal s p i n e s on t e r g i t e 8; f i l a m e n t o u s p o r t i o n o f 7 t h p a i r o f g i l l s p r e s e n t . D i s t r i b u t i o n : B r i t i s h C olumbia M a t e r i a l Examined; 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) 11.15.60 ( N . J . F i l m e r ) H e p t a q e n i a sp. 7  A d u l t : Unknown Nymph: F r o n t a l p l a t e o f head extends beyond the a n t e r i o r h a l f of t h e l a t e r a l edges o f the e y e s , f o u r p a l e s p o t s on the a n t e r i o r and l a t e r a l m a rgins o f the f r o n t a l p l a t e ; pronotum w i d e s t a t t h e a n t e r i o r m a r g i n ; c l a w s l a c k i n g i n p e c t i n a t i o n s ; abdominal t e r g i t e s w i t h 2 p a l e s p o t s l a t e r a l l y on each; t e r g i t e s w i t h no submedian p a l e s t r e a k s ; t e r g i t e s 8 and 9 dark; no abdominal s p i n e s on t e r g i t e 8; f i l a m e n t o u s p o r t i o n of 7 t h p a i r o f g i l l s p r e s e n t . E c o l o g y : Specimens of t h i s s p e c i e s were t a k e n from the m i d d l e and edge of t h e A l o u e t t e R i v e r , from stream beds v a r y i n g from s i l t , t h r o u g h sand, mud, g r a v e l , r o c k s , b o u l d e r s , t o b e d r o c k , a t a depth of 1 to 2 f e e t . The m a j o r i t y were t a k e n from the edges of the r i v e r . The c u r r e n t was q u i e t o r r i p p l e y i n t h e s e l o c a t i o n s . A l l were t a k e n from J u l y 28 to August 11, 1959. -95-D i s t r i b u t i o n : B r i t i s h C olumbia m a t e r i a l Examined: 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) VII.28.59 (N.j". F i l m e r ) ; 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) V I I I . 1 1 . 5 9 ( N . J . F i l m e r ) ; 5 Nymphs, B r i t i s h C o l u m b i a : N i c o l a Creek H e p t a g e n i a sp. 8  A d u l t : Unknown Nymph: F r o n t a l p l a t e o f head e x t e n d s beyond the eyes; t h r e e p a l e s p o t s between the eyes and the a n t e n n a l b a s e s ; pronotum w i d e s t near the m i d d l e ; femora brown w i t h the b a s a l p a r t p a l e and b e a r i n g a p a l e z i g z a g mark; t a r s u s brown w i t h m i d d l e p a r t p a l e ; c l a w s w i t h o u t p e c t -i n a t i o n s ; abdominal t e r g i t e s brown; t e r g i t e 4 w i t h a p a l e o b l o n g p a t c h on i t s p o s t e r i o r m a r g i n ; t e r g i t e 8 l a r g e l y p a l e ; no abdominal s p i n e s on t e r g i t e 8; f i l a m e n t o u s p o r t i o n o f 7 t h p a i r of g i l l s w a n t i n g . D i s t r i b u t i o n : B r i t i s h Columbia m a t e r i a l Examined: 43 Nymphs, B r i t i s h C o l u m b i a : N i c o l a Creek. GENUS RITHRDGENA EATON R i t h r o q e n a , Needham, 1935, The B i o l o g y of m a y f l i e s , 369 ( B i b l i o g r a p h y ) A d u l t : medium to l a r g e , dark brown or r e d d i s h brown m a y f l i e s ; eyes of male l a r g e , u s u a l l y c o n t i g u o u s a p i c a l l y ; p o s t e r i o r margin o f pronotum d e e p l y e x c a v a t e d m e d i a l l y ; f o r e l e g of male l o n g e r than body, o f f e m a l e , s l i g h t l y l e s s than or e q u a l t o l e n g t h o f body; f o r e femur of male 3/4 the l e n g t h of the t i b i a , which i s 3/4 the l e n g t h of the t a r s u s ; b a s a l f o r e t a r s a l j o i n t l / 6 to l / 4 the l e n g t h o f the 2nd j o i n t ; f o r e femur o f f e m a l e 3/4 the l e n g t h of the t i b i a , which i s about t w i c e as l o n g as the t a r s u s ; b a s a l f o r e t a r s a l j o i n t l / 2 the l e n g t h o f the 2nd j o i n t ; i n h i n d l e g o f both s e x e s , t i b i a 1/4 the l e n g t h of the femur; t a r s u s l / 2 or l e s s t h a n 1/2 the l e n g t h o f the t i b i a ; a l l c l a w s d i s s i m i l a r ; t y p i c a l H e p t a g e i n i n e wing v e n a t i o n ; s t i g m a t i c c r o s s v e i n s anastomosed and s l a n t e d ; b a s a l c o s t a l and s u b c o s t a l c r o s s v e i n s weak; Of o f Rs of h i n d wing p r e s e n t ; second f o r k o f Rs u s u a l l y a r i s e s basad of f i r s t f o r k ; a p i c a l margin of f o r c e p s base of male u s u a l l y s l i g h t l y e x c a v a t e d m e d i a l l y , f l a n k e d by two s l i g h t l y rounded p r o j e c t i o n s ; f o r c e p s 4 - j o i n t e d , 2nd j o i n t l o n g and s l e n d e r ; penes u s u a l l y r o d -shaped, s e p a r a t e d v e r y near t h e base; s p i n e s u s u a l l y p r e s e n t on penes; s u b a n a l p l a t e o f female w e l l - d e v e l o p e d , a p i c a l margin- e n t i r e , u s u a l l y o b t u s e l y rounded. Nymph: Head f l a t t e n e d and s l i g h t l y d e f l e x e d ; f r o n t a l margin e n t i r e and s l i g h t l y e m a r g i nate m e d i a l l y ; head w i d e s t a t l e v e l o f the a n t e r i o r p o r t i o n o f the eyes; labrum 4 t i m e s as wide as l o n g , a n t e r i o r margin s l i g h t l y e m a r g i nate m e d i a l l y ; o u t e r c a n i n e s o f m a n d i b l e s a t l e a s t t w i c e the l e n g t h o f the i n n e r ones, s l a n t i n g o b l i q u e l y i n w a r d s , and s h a r p l y t r u n c a t e a t t h e i r o u t e r bases o p p o s i t e the i n n e r c a n i n e s ; l a c i n i a r e p l a c e d by a row of f i n e l y p e c t i n a t e s p i n e s ; crown of g a l e a - l a c i n i a b e a r i n g a s e r i e s o f p e c t i n a t e s p i n e s ; m a x i l l a r y p a l p i 2 - j o i n t e d , f i r s t j o i n t d i l a t e d b r o a d l y near t h e base, 2nd j o i n t s t o u t l y c l a v a t e , o b l i q u e a p i c a l l y ^ s h o r t e r than 4 t i m e s the l e n g t h o f the g a l e a - l a c i n i a , b e a r i n g many p a r a l l e l s e r i e s of p e c t i n a t e s p i n e s ; g l o s s a e of l a b i u m c o n i c a l , w i d e l y s e p a r a t e d a t base, u s u a l l y s l i g h t l y d i v e r g e n t a p i c a l l y ; -97-l a t e r a l margins o f pronotum f l a r e s l i g h t l y near a n t e r i o r margin; p o s t e r i o r margin e x c a v a t e d m e d i a l l y ; femur f l a t t e n e d , upper s u r f a c e and m a rgins b e a r i n g , many minute s p i n e - l i k e p r o c e s s e s , t h o s e on p o s t e r i o r margin l o n g e r ; femur s u b e q u a l t o or s l i g h t l y l o n g e r t h a n t i b i a ; t i b i a u s u a l l y w i t h a few s h o r t s p i n e s on median p o r t i o n o f upper s u r f a c e and a l o n g m a r g i n s ; t i b i a more th a n t w i c e the l e n g t h o f the t a r s u s ; c l a w s w i t h a s i n g l e s t o u t s p i n e l / 3 the d i s t a n c e from the base on the i n n e r margin and 2 or 3 s m a l l e r p e c t i n a t i o n s l a t e r a l l y near apex; abdominal t e r g i t e s each b e a r i n g a s h o r t a n t e r i o r and a b l u n t p o s t e r i o r s p i n e - l i k e p r o c e s s l a t e r a l l y near bases o f g i l l s ; g i l l s on segment 1-7, c o n s i s t i n g o f a l a m e l l a t e "and a f i b r i l l a r p o r t i o n ; f i b r i l l a r p o r t i o n s d o r s a l , may be w a n t i n g on segment 7; a n t e r i o r l o b e of 1 s t and p o s t e r i o r l o b e of 7 t h p a i r s of g i l l s e n l a r g e d and e l o n g a t e d , meeting beneath the body; o t h e r g i l l s o v a l , each o v e r l a p p i n g t h e one b e h i n d i t , f o r m i n g a " s u c k e r d i s c " ; l a t e r a l m a r g ins of l a m e l l a e not t h i c k e n e d and bear no f i n g e r l i k e p r o j e c t i o n ; 7 t h l a m e l l a e always show t r a c h e a e w i t h l a t e r a l b r a n c h e s ; t h r e e t a i l s , m i d d l e t a i l f r i n g e d w i t h f i n e h a i r s on each s i d e , e x c e p t i n b a s a l t h i r d ; o u t e r t a i l s f r i n g e d i n a p i c a l 2/3 on i n n e r margin o n l y . Genotype: R i t h r o q e n a s e m i c o l o r a t a ( i n B a e t i s ) C u r t i s RITHROGENA Key To A d u l t s 1. Brunnea type o f g e n i t a l i a ( f i g . ^ ) 2. Not t h i s t y p e of g e n i t a l i a 4. 2. F i v e t o s i x s m a l l a p i c a l v e n t r a l s p i n e s m o r r i s o n i Banks -98-No prominent s p i n e s on i n n e r a p i c a l margin of penes.. 3. 3. S m a l l sharp s p i n e p r e s e n t on . l a t e r o - a p i c a l margin cn each d i v i s i o n o f penes..... v i r i l i s IticD No s m a l l sharp s p i n e p r e s e n t on l a t e r o - a p i c a l margin o f penes... d o d d s i McD 4. G e n i t a l i a o f r o b u s t a t y p e ( f i g . 3 ) . No marks on femur. S t r o n g l a t e r a l s p i n e p r e s e n t on each d i v i s i o n o f penes near base,,, r o b u s t a Dodds G e n i t a l i a o f j e j u n a ( f i g . 3) t y p e . S t r e a k on femur. No l a t e r a l s p i n e s on penes, o r s p i n e - b e a r i n g p r o c e s s . . . . . j e j u n a Eaton KeyTo Nymphs 1. G i l l s c o l o u r l e s s 2. G i l l s , r o s e or t i n g e d w i t h p u r p l i s h i n the d o r s a l h a l f . 5. 2. Each g i l l w i t h a s e t o s e r i d g e on the v e n t r a l s i d e 3. No s e t o s e r i d g e on the v e n t r a l s i d e of g i l l s 4. 3. Labrum w i t h a s l i g h t i n d e n t a t i o n i n the m i d l i n e . T r a c h e a t i o n i n the p r o x i m a l h a l f of g i l l s r o b u s t a Dodds Labrum w i t h no i n d e n t a t i o n i n the m i d l i n e . No t r a c h e a t i o n v i s i b l e i n g i l l s sp. 1 4. I n t e r m e d i a t e p a i r s o f g i l l s each bear a rounded, e a r - l i k e e r e c t d o r s a l l o b e .sp. 2 No e r e c t d o r s a l l o b e on g i l l s s p . 3 5. T e r g i t e s red-brown - . m o r r i s o n i Banks T e r g i t e s not red-brown 6. 6. I n t e r m e d i a t e p a i r s o f g i l l s each bear a rounded, e a r - l i k e e r e c t d o r s a l l o b e . T e r g i t e s green brown. G i l l s b r i g h t r o s e p i n k d o d d s i flflcD. No e r e c t d o r s a l l o b e s on g i l l s . T e r g i t e s brown. G i l l s t i n g e d -99-w i t h p u r p l i s h i n the d o r s a l h a l f v i r i l i s IYlcD Unknown: R i t h r o q e n a .je.juna Eaton RITHROGENA DODDS I McDUNNOUGH R i t h r o q e n a d o d d s i McDunnough, Needham, 1935, The B i o l o g y of M a y f l i e s , 376 ( B i b l i o g r a p h y ) A d u l t : A brown s p e c i e s ; l e g s dark umber-brown; femora w i t h a dark l o n g i t u d i n a l s t r e a k i n b a s a l h a l v e s , e n t i r e femur may appear shaded w i t h b l a c k ; wings h y a l i n e ; v e n a t i o n - f i n e , dark brawn; b a s a l c o s t a l c r o s s v e i n s o b s o l e s c e n t : abdominal t e r g i t e s brown, i n t e r s e g m e n t a l a r e a s p a l e r ; l a t e r o - a p i c a l a n g l e s of t e r g i t e s rounded, w i t h no s m a l l sharp s p i n e ; s t e r n i t e s d u l l y e l l o w i s h brown; g e n i t a l i a of brunnea t y p e ; penes a l m o s t s t r a i g h t , l o n g and s l e n d e r , s l i g h t l y d i v e r g e n t but n ot o u t c u r v e d o r t r u n c a t e a p i c a l l y ; eadh d i v i s i o n b road a t apex; s t r o n g l a t e r a l s p i n e p r e s e n t on each d i v i s i o n o f penes, near base, and a v e n t r a l s p i n e , near i n n e r m a r g i n , on each d i v i s i o n i n c e n t r a l p o r t i o n ; l a t e r o - a p i c a l s p i n e s on penes m i n u t e . Nymph: Abdominal t e r g i t e s green-brown; g i l l s b r i g h t r o s e - p i n k i n c o l o u r ; i n t e r m e d i a t e p a i r s o f g i l l s each bear a rounded, e a r - l i k e e r e c t d o r s a l l o b e . D i s t r i b u t i o n ' : B r i t i s h C olumbia No specimens o f t h i s s p e c i e s were examined. -100-RITHRQGENA 3E3UNA EATON R i t h r o q e n a j e j u n a E a t o n , Needham, 1935, The B i o l o g y o f M a y f l i e s , 380 ( B i b l i o g r a p h y ) A d u l t : A dark brown s p e c i e s ; l e g s s o o t y brown; femora each w i t h a b l a c k l o n g i t u d i n a l s t r e a k , b e g i n n i n g near base and t a p e r e d a t each end; wings h y a l i n e ; f a i n t g r e y i s h t i n t ; v e n a t i o n v e r y dark brown; many c o s t a l c r o s s v e i n s anastomosed; abdominal t e r g i t e s 2-5 t r a n s l u c e n t burnt-umber brown; p o s t e r i o r margins d a r k e r ; s t e r n i t e s p a l e r ; a p i c a l t e r g i t e s opaque; g e n i t a l i a of j e j u n a t y p e ; penes s t r o n g l y o u t c u r v e d a t t i p s ; penes d i s t i n c t l y narrowed a p i c a l l y ; no s m a l l s p i n e s a p i c a l l y on d i v i s i o n s ; no l a t e r a l s p i n e o r s p i n e b e a r i n g p r o c e s s on penes; a p i c a l margin o f f o r c e p s base p r o j e c t i n g backward w i t h a d i s t i n c t rounded median e x c a v a t i o n . Nymph: Unknown D i s t r i b u t i o n : Quebec, B r i t i s h Columbia No specimens of t h i s s p e c i e s were examined. RITHROGENA IY10RRIS0NI BANKS R i t h r o q e n a m o r r i s o n i Banks, Needham, 1935, The B i o l o g y o f M a y f l i e s , 381 ( B i b l i o g r a p h y ) A d u l t : A dark brown s p e c i e s ; f o r e l e g s brown, o t h e r l e g s p a l e r ; femora of l a t t e r w i t h dark brown s t r e a k s ; wings h y a l i n e ; v e n a t i o n f i n e , brown; humeral c r o s s v e i n s deep b l a c k i s h : s t i g m a t i c a r e a smoky; c r o s s -v e i n s m o s t l y anastomosed or f o r k i n g ; a b d o m i n a l t e r g i t e s d u l l brown, a p i c a l ones d a r k e r ; p o s t e r i o r margins d a r k e r ; l a t e r a l m a r gins p a l e y e l l o w i s h ; s t e r n i t e s d u l l y e l l o w i s h ; g e n i t a l i a o f brunnea t y p e ; penes -101-r e l a t i v e l y l o n g and s l e n d e r , s t r o n g l y d i v e r g e n t a p i c a l l y , narrowed a t apex w i t h l a t e r a l a p i c a l margins rounded; each d i v i s i o n w i t h a s t r o n g l a t e r a l s p i n e and a s m a l l d i s t i n c t v e n t r a l s p i n e near i n n e r m argin i n c e n t r a l p o r t i o n ; and 5-6 s m a l l a p i c a l v e n t r a l s p i n e s . Nymph: A red-brown s p e c i e s ; l e g s p a l e ; o u t e r s u r f a c e o f femora brown, each w i t h a l a r g e median dark brown s p o t and b l a c k apex; abdominal t e r g i t e s 8-10 w i t h p a l e submedian s p o t s ; g i l l s sometimes r o s e - t i n t e d . D i s t r i b u t i o n : B r i t i s h C o l umbia No specimens of t h i s s p e c i e s were examined. RITHROGENA ROBUSTA DODDS R i t h r o g e n a r o b u s t a Dodds, Needham, 1935, The B i o l o g y of M a y f l i e s , 382 ( B i b l i o g r a p h y ) A d u l t : A l a r g e dark brown s p e c i e s ; f o r e l e g s dark brown, o t h e r l e g s s l i g h t l y p a l e r brown; no marks on femora a l t h o u g h the a p i c e s are d a r k e r brown; wings h y a l i n e ; not t i n t e d , e x c e p t i n s t i g m a t i c a r e a , which i s b r o w n - t i n g e d ; v e n a t i o n dark brown; humeral c r o s s v e i n s l i g h t r e d -brown, p a l e at c o s t a l m a r g i n ; b a s a l c o s t a l and s u b c o s t a l c r o s s v e i n s p a l e and f a i n t ; s t i g m a t i c c o s t a l c r o s s v e i n s anastomosed; abdominal t e r g i t e s 2-7 s e m i - h y a l i n e , dark red-brown; l a t e r a l and p o s t e r i o r m argins and i n t e r s e g m e n t a l a r e a s p a l e y e l l o w i s h brown; each t e r g i t e w i t h a narrow p a l e r mid d o r s a l l i n e and p a l e h y a l i n e wedge-shaped submedian s t r e a k s near c e n t e r ; t e r g i t e s 8-10 opaque, a l m o s t b l a c k -brown; s t e r n i t e s p a l e red-brown w i t h g a n g l i o n i c a r e a s o u t l i n e d i n dark brown i n most segments; g a n g l i o n i c a r e a s b l a c k i s h i n a p i c a l segments; g e n i t a l i a o f r o b u s t a t y p e ; d i v i s i o n s of penes r e l a t i v e l y s h o r t and s t o u t , w i d e l y d i v e r g e n t a p i c a l l y , r o u n d l y t r u n c a t e a t t i p s ; -102-a s t r o n g l a t e r a l s p i n e - l i k e p r o c e s s i s p r e s e n t on each d i v i s i o n , the o u t e r s h o r t and s t o u t , and the l a r g e r on the i n n e r margin w i t h i t s t i p s l i g h t l y c u r v e d i n w a r d and the s m a l l e r one d i r e c t e d upuiard. Nymph: G i l l s c o l o u r l e s s , no e r e c t d o r s a l l o b e on g i l l s . D i s t r i b u t i o n : B r i t i s h Columbia No specimens of t h i s s p e c i e s were examined. RITHROGENA UIRIL I S McDUNNOUGH R i t h r o q e n a v i r i l i s McDunnough, Needham, 1935, The B i o l o g y of M a y f l i e s , 384 ( B i b l i o g r a p h y ) A d u l t : A l a r g e brown s p e c i e s ; f o r e l e g s deep smoky; o t h e r l e g s l i g h t e r brown; a l l femora w i t h a l o n g i t u d i n a l dark s t r e a k ; wings h y a l i n e ; c o s t a f a i n t l y a m b e r - t i n g e d ; v e n a t i o n f i n e , dark brown; s t i g m a t i c c r o s s v e i n s anastomosed; abdominal t e r g i t e s brown w i t h i r r e g u l a r p a l e r l a t e r a l m a r g i n s ; s t e r n i t e s brown, p o s t e r i o r s t e r n i t e s p a l e r ; g e n i t a l i a o f brunnea t y p e ; d i v i s i o n s of penes r e l a t i v e l y l o n g and s l e n d e r , not t r u n c a t e a p i c a l l y ; a s t r o n g l a t e r a l s p i n e p r e s e n t near base of each d i v i s i o n ; no p r ominent s p i n e on i n n e r a p i c a l m a r g i n s , but on each l a t e r a l a p i c a l margin i s a s m a l l sharp s p i n e . Nymph: T e r g i t e s brown; g i l l s t i n g e d w i t h p u r p l i s h i n the d o r s a l h a l f ; no e r e c t d o r s a l l o b e on g i l l s . D i s t r i b u t i o n : A l b e r t a , B r i t i s h Columbia No specimens of t h i s s p e c i e s were examined. R i t h r o q e n a s p. 1 A d u l t : Unknown: -103-IMymph: G i l l s c o l o u r l e s s ; f i r s t and l a s t g i l l s meeting beneath the body; each g i l l u/ith a s e t o s e r i d g e on the v e n t r a l s i d e ; no t r a c h e a t i o n v i s i b l e i n the g i l l s ; a s m a l l dark square on the 7 t h s t e r n i t e , labrum w i t h no i n d e n t a t i o n i n m i d l i n e . D i s t r i b u t i o n : B r i t i s h C olumbia M a t e r i a l Examined; 3 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) XI.26.59 ( N . J . F i l m e r ) 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) XI.8.59 ( N . J . F i l m e r ) R i t h r o o e n a s p . 2  A d u l t : Unknown Nymph: G i l l s c o l o u r l e s s ; no s e t o s e r i d g e on v e n t r a l s i d e o f g i l l s ; i n t e r m e d i a t e p a i r s of g i l l s each bear an e r e c t rounded e a r - l i k e l o b e ; f i r s t p a i r o f g i l l s meet beneath the body. D i s t r i b u t i o n : B r i t i s h C olumbia m a t e r i a l Examined: 10 Nymphs, B r i t i s h C o l u m b i a : Loon Creek, (H. L o r g ) ; 1 Nymph, B r i t i s h C o l u m b i a : Loon Creek H a t c h e r y Ponds, C l i n t o n , VI.16.56 (H. L o r z ) ; 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C. ) V.14.59, ( N . J . F i l m e r ) R i t h r o q e n a sp. 3  A d u l t : Unknown Nymph: A u n i c o l o u r e d brown s p e c i e s ; g i l l s p a l e ; no s e t o s e r i d g e on v e n t r a l s i d e of g i l l s ; no e r e c t d o r s a l l o b e on g i l l s ; no t r a c h e a t i o n -104-on g i l l s ; no i n d e n t a t i o n on m i d l i n e o f labr u m . D i s t r i b u t i o n : B r i t i s h C olumbia M a t e r i a l Examined: 2 Nymphs, B r i t i s h C o l u m b i a : Loon Creek, C l i n t o n , VI.16.56 (H. L o r z ) GENUS STENQNEMA TRAVER Stenonema, Needham, 1935, The B i o l o g y o f M a y f l i e s , 295 ( B i b l i o g r a p h y ) A d u l t : S m a l l t o moderate s i z e d m a y f l i e s ; eyes of male moderate s i z e , n o t c o n t i g u o u s a p i c a l l y ; p o s t e r i o r margin o f pronotum d e e p l y e x c a v a t e d m e d i a l l y ; f o r e l e g of male as l o n g o r s l i g h t l y l o n g e r than body; f o r e femur o f male 3/4 as l o n g as t i b i a , u/hich i s 3/4 as l o n g as the t a r s u s ; b a s a l f o r e t a r s a l j o i n t l / 3 t o l / 2 as l o n g as the second; f o r e femur o f female s u b e q u a l or s l i g h t l y s h o r t e r than t i b i a , which i s s l i g h t l y l o n g e r t h a n the t a r s u s ; i n h i n d l e g of both s e x e s , femur s u b e q u a l o r s l i g h t l y l o n g e r than t i b i a , which i s t w i c e as l o n g as the t a r s u s ; a l l c l a w s d i s s i m i l a r ; t y p i c a l Heptagenine wing v e n a t i o n ; b a s a l c o s t a l c r o s s v e i n s s t r o n g ; c r o s s v e i n s a t and below the b u l l a may be crowded; s t i g m a t i c c r o s s v e i n s s l a n t e d , not anastomosed, though a few may be f o r k e d ; c o s t a l c r o s s v e i n s and t h o s e a t b u l l a may be dark margined; Of of Rs o f h i n d margin p r e s e n t ; f o r c e p s 4 - j o i n t e d ; a p i c a l margin o f f o r c e p s base not de e p l y e x c a v a t e d ; penes more o r l e s s d i s t i n c t l y L-shaped; d i v i s i o n o f penes w i t h a p a i r of s t o u t median s p i n e s , may be s m a l l e r l a t e r a l and a p i c a l s p i n e s ; s u b a n a l p l a t e o f female w e l l d e v e l o p e d , e x t e n d i n g beyond 10th segment, i t s a p i c a l m argin e n t i r e , t r u n c a t e or v e r y s l i g h t l y e m a r g i n a t e i n m i d d l e a r e a . Nymph: F r o n t o f head may be s l i g h t l y e m a r g i n a t e ; i n n e r mandibulan c a n i n e about 7/8 as l o n g as the o u t e r one; upper crown o f g a l e a - l a c i n i a -105-b e a r s b o t h s p i n e s and h a i r s or a row of p e c t i n a t e s p i n e s ; m a x i l l a r y p a l p i 2 - j o i n t e d , second j o i n t s h o r t e r than 4 t i m e s the l e n g t h of the g a l e a - l a c i n i a ; c l a w s may or may not have p e c t i n a t i o n s ; g i l l s c o n s i s t o f a l a m e l l a t e and a f i b r i l l a r p o r t i o n ; f i b r i l l a r p o r t i o n v e n t r a l ; no f i n g e r l i k e p r o j e c t i o n s on g i l l l a m e l l a e ; g i l l s do not meet beneath the body; l a m e l l a t e p o r t i o n of g i l l s may be rounded, t r u n c a t e or p o i n t e d a t apex; g i l l s of -7th segment t h r e a d l i k e or s p i n e -l i k e ; t h i s g i l l may c o n t a i n a s i n g l e t r a c h e a w i t h no l a t e r a l branches or a s i n g l e v ' f o r k e d t r a c h e a , and may be f r i n g e d w i t h l o n g h a i r s or may have a few f i n e h a i r s a l o n g the m a r g i n ; s p i n e s on p o s t e r o - l a t e r a l a n g l e s of a p i c a l t e r g i t e s , and may or may not be p r e s e n t on m i d d l e t e r g i t e s : t a i l s t h r e e . Genotype: Stenonema t r i p u n c t a t u m ( i n H e p t o q e n i a ) Banks STEN0NEIY1A TER1Y11MATU1Y1 (UJALSH) Stenonema terminatum ( W a l s h ) , Needham, 1935, The B i o l o g y of M a y f l i e s , \ .Spieth and I d e , 1939, Can. E n t . 71:167 ( B i b l i o g r a p h y ) A d u l t : A l i g h t ruddy s p e c i e s ; head y e l l o w i s h ; notum r e d d i s h to dark o l i v e brown, f o r e femora y e l l o w i s h , w i t h i n d i s t i n c t m i d d l e and a p i c a l ruddy bands; b a s a l j o i n t of f o r e t a r s u s l e s s than l / 2 or l i t t l e more than l / 3 the l e n g t h of the second; s c u t e l l u m w h i t i s h a t t i p ; wings h y a l i n e ; l o n g i t u d i n a l v e i n s o f c o s t a l margin y e l l o w i s h , r e s t r e d -brown; b a s a l c o s t a l and s u b c o s t a l c r o s s v e i n s t h i c k e n e d e q u a l l y , not more i n the c e n t e r than e l s e w h e r e ; c r o s s v e i n s a t and below the b u l l a , i n 1 s t t h r e e s p a c e s , a r r a n g e d as 1,1,1 - 1,2,1 - 1,2,2 - or 1,2,3 - o r 2,2,2 - s t i g m a t i c a r e a s l i g h t l y c l o u d y , not d a r k - s t a i n e d ; h i n d wing -106-v e n a t i o n h y a l i n e ; not da r k - m a r g i n e d ; abdominal t e r g i t e s 1-6 h y a l i n e w h i t i s h , p o s t e r i o r margins n a r r o w l y or w i d e l y red-brown i n d o r s a l p o r t i o n s ; a n t e r i o r h a l f o f t e r g i t e 7 h y a l i n e w h i t i s h , p o s t e r i o r h a l f opaque red-brown; t e r g i t e s 8-10 opaque r e d brown; no s p i r a c u l a r d o t s ; s t e r n i t e s p a l e r ; g e n i t a l i a of p u l c h e l l u m type ( f i g . 3 ) ; t a i l s w h o l l y p a l e , not d a r k e r a t j o i n i n g s , o r . p u r p l i s h a t b a s a l j o i n i n g s and o t h e r s f a i n t l y , d a r k . Nymph: T e r g i t e 7 l a r g e l y d a r k ; 2 narrow p a l e submedian s t r e a k s and narrow p a l e l i n e n e x t t o p o s t e r i o r m a r g i n ; a dark l a t e r a l mark on each s i d e of s t e r n i t e 9; dark v e n t r a l markings on segments 8, 9, or 9 o n l y ; P o s t e r i o r l a t e r a l s p i n e s on segments 7-9 o n l y ; s p i n e on segment 8 l o n g e r than 9; dorsium o f abdomen w i t h a d i s t i n c t p a t t e r n o f p a l e and dark a r e a s ; abdominal segments w i t h o u t dark c o n s p i c u o u s p o s t e r i o r bands d o r s a l l y and v e n t r a l l y ; g i l l s on segments 1-6 t r u n c a t e a t apex; 7 t h g i l l w i t h o u t a t r a c h e a ; c l a w s not toothed.. D i s t r i b u t i o n : Idaho, M a n i t o b a , B r i t i s h Columbia No specimens o f t h i s ' s p e c i e s were examined. SUBFAMILY METRETOPODINAE A d u l t : Eyes of male not t u r b i n a t e ; eyes o f male e n t i r e , a h o r i z o n t a l l i n e on the s u r f a c e d i v i d i n g each i n t o two a r e a s ; t a r s i f i v e - j o i n t e d , the b a s a l j o i n t , e x c e p t i n the f o r e l e g of the male, c o m p l e t e l y f u s e d w i t h the t i b i a ; f i r s t t a r s a l j o i n t s of m i d d l e and h i n d l e g s as l o n g or s l i g h t l y l o n g e r than the second; femora of m i d d l e and h i n d leg's -107-l o n g e r t h a n the t i b i a e ; a l l clauis d i s s i m i l a r ; Of of f o r e w i n g and p o s t e r i o r branch of the IY1 n o r m a l , a t t a c h e d b a s a i l y ; c u b i t a l i n t e r -c a l a r i e s . 2-4 i n number, f r e e b a s a i l y , not f o r k i n g or s i n u a t e o r j o i n e d t o the h i n d margin by c r o s s v e i n s ; 1 s t a n a l v e i n ends i n h i n d m a r g i n ; c o s t a l a n g u l a t i o n o f h i n d wing v a r i a b l e , Of p r e s e n t ; f o r c e p s base r o u n d l y e x c a v a t e d i n h i n d m a r g i n ; f o r c e p s 4 - j o i n t e d ; second j o i n t l o n g e s t ; penes may be u n i t e d a t apex or d i v i d e d h a l f - w a y from base i n t o rod-shaped p o r t i o n s ; s u b a n a l p l a t e of f e m a l e v a r i a b l e ; t a i l s two. Nymph; Nymph not d e p r e s s e d ; eyes and/or antennae l a t e r a l , a n t e r o - l a t e r a l , o r a n t e r i o r ; no s e t a e on l a t e r o - l a t e r a l a n g l e s of head; no s e t a e on i n n e r s u r f a c e of f o r e l e g s ; no g i l l t u f t s on m a x i l l a e o r f o r e coxae; c l a w s o f f o r e - l e g b i f i d ; c l a w s o f m i d d l e and h i n d l e g s l o n g and s l e n d e r , about as l o n g as the s h o r t t i b i a ; g i l l s on segments 1-7, r a r e l y on 1-5; g i l l s d o r s a l and w i t h o u t a f r i n g e d m a r g i n ; o u t e r t a i l s f r i n g e d on i n n e r s i d e only,, o r t h e r e may be a few s h o r t h a i r s on the o u t e r s i d e . GENUS WETRETOPUS EATON M e t r e t o p u s , Needham, 1935, The B i o l o g y o f M a y f l i e s , 434 ( B i b l i o g r a p h y ) A d u l t ; • A medium s i z e d b r o w n i s h s p e c i e s ; f o r e femur o f male about l / 2 the l e n g t h of the t i b i a , which i s l / 3 the l e n g t h o f the t a r s u s ; 1 s t t a r s a l j o i n t s u b e q u a l t o the second; i n the f e m a l e , the femur and the t i b i a a r e s u b e q u a l ; the t i b i a i s about 3/4 t h e l e n g t h o f the t a r s u s ; 1 s t t a r s a l j o i n t about 1-1/3 t i m e s t he l e n g t h of the second; a l l c l a w s d i s s i m i l a r ; f o r e w i n g w i t h a s i n g l e p a i r of c u b i t a l i n t e r -^•108-c a l a r i e s , the a n t e r i o r v e i n b e i n g the l o n g e s t ; s t i g m a t i c c r o s s v e i n s t e n d t o anastomose; c o s t a l a n g u l a t i o n of h i n d wing a c u t e ; IYI2 n o r m a l , f o r k e d near the base; f o r c e p s base r o u n d l y e x c a v a t e d i n a p i c a l m a r g i n ; f o r c e p s 4 - j o i n t e d , the f i r s t 2 j o i n t s more o r l e s s f u s e d ; penes d i v i d e d i n the a p i c a l h a l f i n t o two r o d - l i k e s t r u c t u r e s , each c u r v i n g outward s l i g h t l y , w i t h a rounded l o b e on the i n n e r a p i c a l m a r g i n ; s u b a n a l p l a t e of female o b t u s e ; t a i l s two, the median t a i l i s r e p r e s e n t e d by a p a r t l y segmented r u d i m e n t . Nymph: M a x i l l a r y p a l p i 2 - j o i n t e d ; b a s a l j o i n t o f l a b i a l p a l p l o n g e r and s t o u t e r than the a p i c a l j o i n t , s w o l l e n on i t s o u t e r m a r g i n ; a p i c a l j o i n t l o n g and t h i n , t h i c k e r on i t s i n n e r s i d e , rounded a p i c a l l y ; f emora about as l o n g as t i b i a e and t a r s i t o g e t h e r ; t a r s i l o n g e r than the t i b i a e ; c l a w s d i s s i m i l a r on f o r e l e g , s i m i l a r on o t h e r s ; g i l l s on segment 1-7, s i m i l a r i n form; a l l g i l l s s i n g l e . Genotype: M e t r e t o p u s n o r v e q i c u s Eaton METRETOPUS BOREALIS EATON M e t r e t o p u s b o r e a l i s E a t o n , Edmunds and A l l e n , 1957, Ann. E n t . Soc. Amer. 50 (4) : 320 ( B i b l i o g r a p h y ) A d u l t : Abdominal t e r g i t e s 1, 7-10 brown, m i d d l e t e r g i t e s t r a n s l u c e n t ; p o s t e r i o r margins of t e r g i t e s n a r r o w l y marked w i t h brown; each t e r g i t e w i t h a brown m i d - d o r s a l l i n e w i t h a dark s t r e a k p r o c e e d i n g f o r w a r d from i t i n each segment to form a t r i a n g l e w i t h the apex d i r e c t e d p o s t e r i o r l y ; t a i l s dark g r e y . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia No specimens o f t h i s s p e c i e s were examined. *109-SUBFAIHILY BAETINAE A d u l t : Eyes of male d i v i d e d , upper p o r t i o n t u r b i n a t e , s e t on a c y l i n d r i c a l s t a l k w i t h f a c e t s on the upper f l a t t e n e d s u r f a c e o n l y ; f a c e t s o f t u r b i n a t e p o r t i o n l o n g e r than th o s e o f lower p o r t i o n ; f o r e t a r s i w i t h 5 j o i n t s , t h e b a s a l j o i n t v e r y s h o r t ; o t h e r t a r s i 4 - j o i n t e d , b a s a l j o i n t p a r t i a l l y f u s e d w i t h t i b i a ; a l l c l a w s d i s -s i m i l a r ; wing v e n a t i o n r e d u c e d ; Of of Rs and p o s t e r i o r b r a n c h of the ITl a r e det a c h e d b a s a i l y from t h e i r r e s p e c t i v e stems; 1 s t ana l \ . v e i n ends i n the h i n d m a r g i n ; b a s a l c o s t a l c r o s s v e i n s o f t e n w a n t i n g ; b e h i n d s u b c o s t a , o t h e r c r o s s v e i n s few i n number and u s u a l l y a r r a n g e d i n s e v e r a l or l e s s d e f i n i t e s e r i e s a c r o s s the wing; 2 l o n g c u b i t a l i n t e r c a l a r i e s p r e s e n t ; s h o r t , w e l l - d e v e l o p e d m a r g i n a l i n t e r c a l a r i e s o c c u r s i n g l y , o r i n p a i r s i n each i n t e r s p a c e between the main v e i n s o r t h e l o n g i n t e r c a l a r i e s ; h i n d wing r e d u c e d i n s i z e , much l o n g e r than wide, or w a n t i n g ; i f p r e s e n t , v e n a t i o n c o n s i s t s of 2 o r 3 l o n g i -t u d i n a l v e i n s and a few or no c r o s s v e i n s ; Of of h i n d wing a b s e n t ; c o s t a l a n g u l a t i o n v a r i a b l e ; i f absent o r g r e a t l y r e d u c e d , a n a l p o r t i o n o f f o r e w i n g g r e a t l y d e v e l o p e d ; t a i l s two; penes i n t e r n a l ; may be a s i n g l e or d i v i d e d " p e n i s c o v e r " between the b a s a l j o i n t s o f the f o r c e p s . Nymph: A s l e n d e r s t r e a m l i n e d s p e c i e s w i t h a downward f l e x e d head and l o n g s l e n d e r l e g s ; antennae l a t e r a l , a n t e r o - l a t e r a l , or a n t e r i o r ; a n t e r o - l a t e r a l a n g l e s o f the head w i t h o u t s e t a e ; f o r e l e g s w i t h o u t a dense row of s e t a e on the i n n e r s u r f a c e ; no g i l l t u f t s on m a x i l l a e -110-o r f o r e c o x a e ; no appendages on f o r e coxae; c l a w s s i m i l a r , s h a r p -p o i n t e d , and much s h o r t e r than the t i b i a e ; c l a w s of the m i d d l e and h i n d l e g s may be l o n g and s l e n d e r , and of the f o r e l e g s s h o r t ; p o s t e r o -l a t e r a l a n g l e s of the a p i c a l abdominal t e r g i t e s u s u a l l y not p r o l o n g e d i n t o f l a t t h i n l a t e r a l s p i n e s , but i f weakly so , the antennae a r e more th a n t w i c e the w i d t h of the head; g i l l s on segments 1-7, and r a r e l y on 1-5 o n l y ; g i l l s l a m e l l a t e , m a rgins e n t i r e ; g i l l s s i n g l e , a p i c a l ones may bear a minute v e n t r a l r e c u r v e d f l a p ; t a i l s 2 or 3, o u t e r ones w i t h a heavy f r i n g e of h a i r s on the i n n e r m a r g i n , and few o r none on the o u t e r ; m i d d l e t a i l , i f p r e s e n t , f r i n g e d on both s i d e s . SUBFAMILY BAETINAE  Key To A d u l t s 1. H ind wings a b s e n t . 2. H i nd wings p r e s e n t 3. 2. M a r g i n a l i n t e r c a l a r i e s of f o r e w i n g o c c u r i n p a i r s . F i r s t j o i n t o f t h i r d t a r s u s s h o r t , e q u a l t o segments 2 and 3... P s e u d o c lo e o n n K l a p a l e k M a r g i n a l i n t e r c a l a r i e s of f o r e w i n g o c c u r s i n g l y . F i r s t j o i n t o f t h i r d t a r s u s l o n g , e q u a l t o segments 2 and 3 and 4 Neocloeon'- T r a v e r 3. Forewing u s u a l l y w i t h numerous c o s t a l c r o s s v e i n s b e f o r e the b u l l a . H i nd wings w i t h a moderate number of c r o s s v e i n s , a t l e a s t i n the c o s t a l r e g i o n C a l l i b a e t i s Eaton Forewing w i t h o u t c o s t a l c r o s s v e i n s b e f o r e the b u l l a . H i nd wings w i t h no c r o s s v e i n s , or w i t h v e r y few. 4. 4. M a r g i n a l i n t e r c a l a r i e s of f o r e w i n g o c c u r i n p a i r s . F i r s t j o i n t o f t h i r d t a r s u s s h o r t , e q u a l to segments 2 and 3. . . . B a e t i s Leach - I l l -m a r g i n a l i n t e r c a l a r i e s o f f o r e w i n g o c c u r s i n g l y . F i r s t j o i n t o f t h i r d t a r s u s l o n g , e q u a l t o segments 2 and 3 and 4. , C e n t r o p t i l u m Eaton Key To Nymphs 1. 3 t a i l s , m i d d l e t a i l may be s h o r t e r than 10th t e r g i t e . . 2. 2 t a i l s P s e u d o c l b e o n , i K l a p a l e k 2. M e t a t h o r a c i c wing pads absent .Neocld.eonn T r a v e r m e t a t h o r a c i c wing pads p r e s e n t , may be minute .3. 3. G i l l l a m e l l a e d o u b l e on abdominal segments 1-6 ( d o r s a l p o r t i o n o f t e n m erely a r e c u r v e d f l a p ) . T a i l s e q u a l 4. G i l l l a m e l l a e s i n g l e on a l l abdominal segments, m i d d l e t a i l s h o r t e r and weaker (may be s h o r t e r t h a n 10th t e r g i t e ) t h a n o u t e r ones B a e t i s Leach 4. Double p o r t i o n o f g i l l i s a f l a p on the v e n t r a l s u r f a c e , m a x i l l a r y p a l p s 2 j o i n t e d . D i s t a l j o i n t of l a b i a l p a l p c o n i c a l . , Claws t o o t h e d . . C a l l i b a e t i s Eaton Double p o r t i o n o f g i l l i s a f l a p on the d o r s a l s u r f a c e , m a x i l l a r y p a l p . 3 j o i n t e d . D i s t a l j o i n t o f l a b i a l p a l p d i l a t e d . Claws not t o o t h e d C e n t r o p t i l u m Eaton GENUS BAETIS LEACH B a e t i s , Needham, 1935, The B i o l o g y o f M a y f l i e s , 674 ( B i b l i o g r a p h y ) A d u l t : S m a l l b r o w n i s h m a y f l i e s ; t u r b i n a t e eyes of male s m a l l , moderate or l a r g e ; eyes of female not t u r b i n a t e , but s m a l l and remote; head o f female w i t h h i n d margin emarginate m e d i a l l y , w i t h a s l i g h t outward p r o l o n g a t i o n on each s i d e o f t h i s e m a r g i n a t i o n ; p r o t h o r a x s m a l l ; a s h o r t p r o t u b e r a n c e near the mi d d l e of the metanotum.; f o r e l e g of male -112-as l o n g as the body; femur 3/4 the l e n g t h of the t i b i a , which i s as l o n g as or s l i g h t l y s h o r t e r than the t a r s u s ; b a s a l t a r s a l j o i n t v e r y s h o r t ; h i n d femur and t i b i a s u b e q u a l , t i b i a l o n g e r t h a n the t a r s u s ; b a s a l t a r s a l j o i n t o f h i n d l e g not l o n g e r than 2nd and 3 r d j o i n t s t o g e t h e r ; m a r g i n a l i n t e r c a l a r i e s of f o r e w i n g o c c u r i n p a i r s ; c o s t a l c r o s s v e i n s w a n t i n g b e f o r e t h e b u l l a ; h i n d wing f a i r l y w e l l d e v e l o p e d ; c o s t a l p r o j e c t i o n u s u a l l y p r e s e n t , may be a c u t e or s l i g h t l y c u r v e d ; 2 or 3 l o n g i t u d i n a l v e i n s , t h e 3 r d , i f p r e s e n t , r a t h e r s h o r t ; no c r o s s v e i n s , or v e r y few; a bdominal t e r g i t e s of female u n i c o l o u r e d r e d d i s h or b r o w n i s h ; of male, 2-6 are u s u a l l y s e m i - h y a l i n e or h y a l i n e , p a l e t o o l i v a c e o u s t o deep brown; 2nd and 3 r d j o i n t s of f o r c e p s f u s e d ; g e n i t a l i a v a r i a b l e . Nymph; Labrum w i t h a d i s t i n c t narrow n o t c h i n the a p i c a l m a r g i n ; m a x i l l a r y p a l p 2 or 3 - j o i n t e d ; l a b i a l p a l p 3 - j o i n t e d , • t h e d i s t a l j o i n t rounded; m e t a t h o r a c i c wing pads p r e s e n t , may be m i n u t e ; c l a w s t o o t h e d on i n n e r m a r g i n ; g i l l s s i n g l e , on segments 1-7; g i l l s o b o v a t e , p i n n a t e l y b r a n c h e d , g i l l s on 6 and 7 may be narrow and l a n c e o l a t e ; u s u a l l y 3 t a i l s , t h e m i d d l e one s h o r t e r and weaker th a n the o t h e r s ; t h e r e may o n l y be 2 t a i l s , o r the t h i r d t a i l may be s h o r t e r than the 10th t e r g i t e . . Genotype: B a e t i s b i o c u l a t u s ( i n Ephemera) L i n n a e u s BAETIS  Key To A d u l t s 1. C o s t a l p r o j e c t i o n of h i n d wing p r o m i n e n t , a c u t e 2. C o s t a l p r o j e c t i o n of h i n d wing w a n t i n g i n s i q n i f i c a n s lYlcD -113-H i nd wing w i t h 2 l o n g i t u d i n a l v e i n s o n l y , e q u a l i n l e n g t h . 3 r d v e i n w h o l l y w a n t i n g b i c a u d a t u s Dodds Hi n d wing w i t h 3 l o n g i t u d i n a l v e i n s . 3 r d v e i n may be s h o r t or weak... • .3. 2nd l o n g i t u d i n a l v e i n o f f o r e w i n g f o r k e d about l / 3 the d i s t a n c e from the base t o the margin p a r v u s Dodds 2nd l o n g i t u d i n a l v e i n o f f o r e w i n g not f o r k e d . . . . . 4. One i n t e r c a l a r y v e i n between v e i n s 2 and 3 of h i n d wing 5. No d e f i n i t e i n t e r c a l a r i e s on h i n d wing p e r s e c u t a IYlcD 3 r d v e i n o f h i n d w i n g e n d i n g near m i d d l e o f . h i n d m a r g i n . i n t e r m e d i u s Dodds 3 r d v e i n o f h i n d w i n g e n d i n g 2/3 a l o n g h i n d margin .jesmondensis IYlcD Key To Nymphs Two t a i l s o n l y ...2. Three t a i l s 3. D i s t i n c t p a l e 3-shaped mark on 1 s t femur, L-shaped on femora 2 and 3. T e r g i t e s 3, 4, and 7 d a r k e r than the o t h e r s '.bicaudatus Dodds No d i s t i n c t 3 or L-shaped marks on femora. T e r g i t e s 3, 4 and 7 not d a r k e r than the o t h e r s . . s p . 1 M i d d l e t a i l about l / 6 the l e n g t h of the o u t e r ones. 4 M i d d l e t a i l a t l e a s t - : l / 2 the l e n g t h of t h e o u t e r ones. 5 F i r s t femur w i t h a J-shaped p a l e mark. Second femur w i t h an L-shaped p a l e mark. A l l t e r g i t e s w i t h p a l e m a r k i n g s , t e r g i t e s 5-8 and 9 p a l e r than the o t h e r s . . . i n t e r m e d i u s - Dodds -114-No 3 b r - L - s h a p e d markings on the femora. T e r g i t e s m o s t l y w i t h -o u t p a l e m a r k i n g s . T e r g i t e s 5, 8 and 9 p a l e r than the o t h e r s , t h o s e on segments 5 and 8 each w i t h two s u b m e d i a l d o t s . . . s p . 2 5. M i d d l e t a i l 3/4 t o 5/6 the l e n g t h of t h e o u t e r ones .......6. M i d d l e t a i l about 1/2 the l e n g t h of the o u t e r ones 9. 6. M i d d l e t a i l a t l e a s t 5/6 the l e n g t h of the o u t e r ones 7 M i d d l e t a i l 3/4 t o 5/6 the l e n g t h of the o u t e r ones..parvus Dodds 7. T e r g i t e s p a t t e r n e d w i t h brown, some p a l e r t h a n o t h e r s . Two p a l e s u b l a t e r a l l i n e s on t e r g i t e s . Wing pads dark o r l i g h t 8. T e r g i t e s p a t t e r n e d w i t h brown, none l i g h t e r than o t h e r s . T e r g i t e s 8, 9, and 10 w i t h l a t e r a l dark l i n e s . Wing pads d a r k . . . s p . 4 8. T e r g i t e s p a t t e r n e d w i t h brown, t e r g i t e s 5, 6, 9 and 10 p a l e r than the o t h e r s . The p a t t e r n on t e r g i t e s 7 and 8 i s a dark t r i a n g l e , apex a n t e r i o r , w i t h a s p o t on each s i d e of the apex. A dark m e d i a l l i n e on t e r g i t e s 9 and 10. UJing pads l i g h t s p. 5 A l l t e r g i t e s brown, t h o s e on segments 8-10 p a l e r , w i t h l a t e r a l and m e d i a l dark bands.- Wing pads dark or l i g h t s p. 6 9. G i l l t r a c h e a t i o n not d i s t i n c t . G i l l s o f average s i z e . . . . . . . s p . 3 G i l l t r a c h e a t i o n d i s t i n c t . G i l l s l a r g e . . . . . . sp. 7 Unknown: B a e t i s i n s i q n i f r a n s McD B a e t i s p e r s e c u t a McD B a e t i s jesmondensis McD BAETIS BICAUDATUS DODDS B a e t i s b i c a u d a t u s Dodds, Needham, 1935, The B i o l o g y of M a y f l i e s , 682 ( B i b l i o g r a p h y ) -115-A d u l t : (Female) A u n i f o r m l y l i g h t brown s p e c i e s ; c o s t a l p r o j e c t i o n of h i n d wing prominent and a c u t e ; h i n d wing w i t h two l o n g i t u d i n a l v e i n s o n l y , which a r e a p p r o x i m a t e l y s u b e q u a l i n l e n g t h . Mymph; Abdominal t e r g i t e s 1 t o 10 p a l e w i t h dark m a r k i n g s , numbers 3, 4 and 7 d i s t i n c t l y d a r k e r than the o t h e r s ; a p p a r e n t l y o n l y two t a i l s , the m i d d l e t a i l b e i n g r e p r e s e n t e d by a minute s t u b . D i s t r i b u t i o n : C o l o r a d o , B r i t i s h C olumbia No specimens of t h i s s p e c i e s were examined. BAETIS INSIGNIFICAN5 lYicDUNNQUGH B a e t i s i n s i q n i f i c a n s lYIcDunnough, Needham, 1935, The B i o l o g y of m a y f l i e s , 692 ( B i b l i o g r a p h y ) A d u l t : T u r b i n a t e eyes s m a l l , b r i g h t r e d ; t h o r a x deep brown w i t h a n t e r i o r p r o j e c t i o n of metanotum p a l e c r e a m - c o l o u r e d ; a l l femora t i n g e d w i t h smoky brown; f o r e femora may be banded a p i c a l l y w i t h b l a c k ; wings h y a l i n e ; v e n a t i o n p a l e ; h i n d wing narrow; c o s t a l p r o j e c t i o n w a n t i n g ; o n l y two l o n g i t u d i n a l v e i n s p r e s e n t , e q u a l i n l e n g t h ; abdominal t e r g i t e s 2-6 p a l e s e m i - h y a l i n e , t i n g e d w i t h smoky brown; t e r g i t e s 7-10 opaque l i g h t s e p i a - b r o w n ; s t e r n i t e s w h i t i s h ; a s h o r t p r o j e c t i n g p l a t e between the bases of the f o r c e p s ; g e n i t a l i a of m o d i f i e d m o f f a t i type ( f i g . 3 ) . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia No specimens of t h i s s p e c i e s were examined. -116-BAETIS INTERMEDIUS DODDS B a e t i s i n t e r m e d i u s Dodds, Needham, 1935, The B i o l o g y o f M a y f l i e s , 693 ( B i b l i o g r a p h y ) A d u l t : Thorax dark brown; h i n d wing t w i c e as l o n g as wide, t h e margins rounded, not p a r a l l e l t o one a n o t h e r ; c o s t a l p r o j e c t i o n w e l l d e v e l o p e d , a c u t e , not c u r v e d ; 3 l o n g i t u d i n a l v e i n s i n h i n d w i n g , f i r s t 2 a p p r o x i -m a t e l y e q u a l i n l e n g t h , . 2 n d not f o r k e d ; 3 r d v e i n f a i n t , r u n n i n g c l o s e t o h i n d m a r g i n , and e n d i n g basad o f m i d d l e on h i n d m a r g i n ; u s u a l l y no c r o s s v e i n s ; one s h o r t i n t e r c a l a r y between v e i n s 2 and 3; abdominal segments 2-6 o l i v a c e o u s to deep brown; g e n i t a l i a of m o f f a t i t y p e ; no t u b e r c l e a t i n n e r a p i c a l margin o f b a s a l f o r c e p s j o i n t ; no exc a v -a t i o n on s p i n e botween the bases o f t h e f o r c e p s . Nymph: G i l l s o f segments 6 and 7 o v a l and rounded; m i d d l e t a i l about l / 6 the l e n g t h o f the o u t e r ones; t a i l s unbanded. D i s t r i b u t i o n : C o l o r a d o , B r i t i s h Columbia No specimens o f t h i s s p e c i e s were examined. BAETIS 3ESMQNDENSIS McDUNNOUGH B a e t i s j e s m o n d e n s i s McDunnough, McDunnough, 1938, Can. E n t . , 70:25 ( B i b l i o g r a p h y ) A d u l t : Eyes o f male r a t h e r s m a l l ; femora l i g h t smoky brown; wings h y a l i n e ; v e n a t i o n f a i n t l y b r o w n - t i n t e d , e s p e c i a l l y t he C and Sc; i n t e r c a l a r i e s o f C and Sc m o d e r a t e l y l o n g but p r a c t i c a l l y l a c k i n g i n 1 s t c o s t a l i n t e r s p a c e ; c r o s s v e i n s h e a v i e r and deeper brown i n fe m a l e ; h i n d wing w i t h 3 l o n g i t u d i n a l v e i n s ; v e i n s 1 and 2 bend a v e r y l i t t l e towards -117-each o t h e r a t o u t e r m a r g i n ; v e i n 3 extends 2/3 the l e n g t h of the h i n d m a r g i n ; c o s t a l p r o j e c t i o n p r o m i n e n t , a c u t e , not c u r v e d ; w e l l d e f i n e d i n t e r c a l a r y between v e i n s 2 and 3; abdominal t e r g i t e s 1-6 s e m i - h y a l i n e , u n i f o r m l y smoky brown, r u d d i e r i n the f e m a l e ; the p o s t e r i o r edges of t h e t e r g i t e s are n a r r o w l y and o b s c u r e l y p a l e ; a n t e r i o r to t h i s i s a f a i n t dark t r a n s v e r s e l i n e i n each t e r g i t e ; a b d ominal t e r g i t e s 7-10 opaque, deep r u s s e t brown. Nymph: Unknown D i s t r i b u t i o n : B r i t i s h C o l umbia No specimens of t h i s s p e c i e s were examined. BAETIS PARVUS DODDS B a e t i s p a r v u s Dodds, Needham, 1935, The B i o l o g y of I T I a y f l i e s , 696 ( B i b l i o g r a p h y ) A d u l t : T u r b i n a t e eyes moderate i n s i z e , dark orange brown i n d r i e d specimens; t h o r a x deep b l a c k i s h brown w i t h the t i p of the s c u t e l l u m p a l e r ; l e g s w h i t i s h ; wings h y a l i n e ; v e n a t i o n p a l e ; f o r e w i n g w i t h 5 t o B s t i g m a t i c c r o s s v e i n s , o f t e n w i t h s h o r t h o r i z o n t a l v e i n s between them, a s l a n t , o f t e n i n c o m p l e t e on the s u b c o s t a l m a r g i n , and sometimes f o r k i n g toward the s u b c o s t a ; u s u a l l y one s h o r t i n t e r c a l a r y i n the f i r s t i n t e r s p a c e , t h o s e of the 2nd i n t e r s p a c e s l i g h t l y s h o r t e r t h a n the f o l l o w i n g p a i r s ; h i n d wing u n u s u a l l y wide f o r i t s l e n g t h ; c o s t a l p r o j e c t i o n w e l l d e v e l o p e d , a c u t e ; 3 l o n g i t u d i n a l v e i n s , the 1 s t and 2nd a p p r o x i m a t e l y e q u a l i n l e n g t h ; the 2nd v e i n f o r k e d about l / 3 the d i s t a n c e from the base; 1, 3 o r 4 i n t e r c a l a r i e s i n t h i s f o r k , one b e i n g l o n g and the o t h e r s s h o r t ; 3 r d v e i n may be weakly d e v e l o p e d , end near m i d d l e of h i n d m a r g i n ; f i r s t abdominal t e r g i t e dark brown,; -118-t e r g i t e s 2-6 h y a l i n e w h i t e ; t e r g i t e s 7-10 opaque, brown, w h o l l y o r p a r t l y s u f f u s e d w i t h deep r o s e ; s t e r n i t e 1 l i g h t brown, r e s t opaque creamy w h i t e , shaded and marked w i t h r o s e ; no dark s p i r a c u l a r m a r k i n g s ; t u b e r c l e on i n n e r a p i c a l margin o f b a s a l f o r c e p s j o i n t a b s e n t or p o o r l y d e v e l o p e d ; g e n i t a l i a of i n t e r c a l a r i e s t y p e . ( f i g . 3) Mymph: G i l l s o f segments 6 and 7 o v a l , rounded; m i d d l e t a i l 3/4 t o 5/6 the l e n g t h of the o u t e r ones; t a i l s unbanded. D i s t r i b u t i o n : IKlontana, Wyoming, A l b e r t a , West V i r g i n i a , B r i t i s h C o l u m bia. M a t e r i a l Examined: No specimens of t h i s s p e c i e s were examined. One v e r y young, w h i t e u n p a t t e r n e d specimen t a k e n by Mr. R. Humphries a t C o r b e t t Lake, B r i t i s h C olumbia (IX.21.63) seems to be of t h i s s p e c i e s . BAETIS PERSECUTA McDUNNOUGH B a e t i s p e r s e c u t a McDunnough, McDunnough, 1939, Can. E n t . , 71:52 ( B i b l i o g r a p h y ) A d u l t : S m a l l o v a l t u r b i n a t e eyes; f o r e femora o f male w h i t i s h , s u f f u s e d w i t h smoky; femora of f e m a l e l i g h t smoky amber; wings h y a l i n e ; v e n a t i o n p a l e i n male, t i n g e d w i t h brown i n f e m a l e ; i n t e r c a l a r i e s o f f i r s t i n t e r s p a c e v e r y weak; c o s t a l p r o j e c t i o n o f h i n d wing w e l l d e v e l o p e d ; t h i r d l o n g i t u d i n a l v e i n weak i n male, o b s o l e s c e n t i n f e m a l e ; no d e f i n i t e i n t e r c a l a r i e s i n h i n d wing; abdominal t e r g i t e s 1-6 o f male h y a l i n e w h i t i s h w i t h a f a i n t smoky t i n g e ; t e r g i t e s 7-10 l i g h t wood-brown; abdominal t e r g i t e s of female brown; g e n i t a l i a o f m o f f a t i t y p e ; i n n e r a p i c a l margin of f i r s t j o i n t of f o r c e p s more b u l g i n g than u s u a l , •119-but not t u b e r c u l a t e . Nymph: Unknown D i s t r i b u t i o n ; B r i t i s h Columbia No specimens o f t h i s s p e c i e s were examined. B a e t i s sp. 1  A d u l t ; Unknown Nymph; L a r g e , s i n g l e g i l l s on segments 1-7; abdominal t e r g i t e s brown, t e r g i t e s 4 and 5 p a l e ; 2 dark s p o t s on each t e r g i t e ; m i d d l e t a i l r e p r e s e n t e d by an unsegmented r u d i m e n t . E c o l o g y ; Specimens of t h i s s p e c i e s were t a k e n from the m i d d l e and edges of the A l o u e t t e R i v e r , from a depth of 1 t o 2 f e e t g e n e r a l l y , a l t h o u g h t h e y have a l s o been c o l l e c t e d a t depths of 2 i n c h e s and 5 f e e t . The s u b s t r a t e s v a r i e d from mud, t h r o u g h sand, g r a v e l , r o c k s , b o u l d e r s , t o b e d r o c k . The most common of t h e s e were c o a r s e g r a v e l and s m a l l r o c k s . The c u r r e n t was u s u a l l y a g e n t l e r i p p l e , a l t h o u g h they have been t a k e n i n r a p i d s and i n q u i e t e r w a t e r . They were c o l l e c t e d the year round. D i s t r i b u t i o n ; B r i t i s h Columbia M a t e r i a l Examined: 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) V.19.59 (N.3. F i l m e r ) ; 2 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) VI.2.59 (N.3. F i l m e r ) ; 1 Nymph, B r i t i s h C o l u m b i a : Loon Creek ( C l i n t o n ) (H. L o r z ) , 2 Nymphs, B r i t i s h C o l u m b i a : Nr. H e l l ' s Gate, VI.19.59 (G.G.E. S c u d d e r ) ; 1 Nymph, B r i t i s h C o l u m b i a : C u l t u s Lake, V.9.59 (G.G.E. S c u d d e r ) , 6 Nymphs, B r i t i s h C o l u m b i a : N i c o l a C r . -120-B a e t i s sp. 2  A d u l t : Unknouin Nymph: L a r g e , s i n g l e g i l l s on segments 1 to 7; abdominal t e r g i t e s 5, 8 and 10 p a l e r than the o t h e r s ; two dark s u b m e d i a l d o t s on t e r g i t e s 5 and 8 or 4 and 5; t a i l s t h r e e , m i d d l e t a i l u s u a l l y l / 6 the l e n g t h of t he l a t e r a l s , but may e x t e n d to 1/2 t h e i r l e n g t h . E c o l o g y : Specimens of t h i s s p e c i e s have been t a k e n from the m i d d l e and edges of v a r i o u s l o c a t i o n s on the A l o u e t t e R i v e r , i n depths of 1 to 5 f e e t , a l t h o u g h g e n e r a l l y they were not found a t a depth g r e a t e r than 2 t o 3 f e e t . The stream bed v a r i e d from mud, t h r o u g h sand, g r a v e l , r o c k s and b o u l d e r s , t o bedr o c k . The c u r r e n t v a r i e d from q u i e t p o o l s t o r a p i d s and f a l l s . T h i s s p e c i e s was t a k e n from Dune 1959 t o the f o l l o w i n g F e b r u a r y . D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: 3 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) VI.23.59 (N.3. F i l m e r ) ; 9 Nymphs, B r i t i s h C o l u m b i a : N i c o l a C r . B a e t i s s p . 3  A d u l t : Unknown Nymph: A v e r a g e - s i z e d , s i n g l e g i l l s on segments 1-7; g i l l t r a c h e a t i o n i n d i s t i n c t ; abdominal t e r g i t e s u n i c o l o u r e d , w i t h no dark m a r k i n g s ; t e r g i t e 5 and 10, or o n l y 10 may be p a l e r ; t a i l s 3, m i d d l e t a i l v a r i e s from l / 2 the l e n g t h of the l a t e r a l s to a l m o s t s u b e q u a l i n l e n g t h t o them. -121-E c o l o q y : Nymphs of t h i s s p e c i e s have been t a k e n from the m i d d l e a i d edges o f v a r i o u s l o c a t i o n s on the A l o u e t t e R i v e r , from depths o f 1 to 3 f e e t , a l t h o u g h o o a s i o n a l l y from deeper, w a t e r . The s u b s t r a t e v a r i e d from mud, th r o u g h sand, g r a v e l , r o c k s , and b o u l d e r s , t o bedrock. The c u r r e n t v a r i e d from q u i e t water t o r a p i d s . They were t a k e n the y e a r round. D i s t r i b u t i o n : B r i t i s h C olumbia M a t e r i a l Examined: 3 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B. c.) V.26.59 ( N . J . F i l m e r ) ; 2 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) VI.9.59 ( N . J . F i l m e r ) ; 2 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) VI.26.59 ( N . J . . F i l m e r ) ; 2 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney, B.C.) VI.16.59 ( N . J . F i l m e r ) . B a e t i s s p . 4  A d u l t : Unknown Nymph: . Front- o f head o c h r e o u s ; wing pads dark brown; a l l abdominal t e r g i t e s brown, none p a l e r than the o t h e r s ; t e r g i t e s B, 9 and 10 w i t h s u b l a t e r a l ' d a r k l i n e s ; t a i l s 3, m i d d l e t a i l 5/6 the l e n g t h o f the l a t e r a l t a i l s . D i s t r i b u t i o n : . B r i t i s h Columbia M a t e r i a l Examined: 1 Nymph, B r i t i s h C o l u m b i a : Squamish, V I I I . 2 5 . 6 1 (G.G.E. S c u d d e r ) ; 1 Nymph, B r i t i s h C o l u mbia: Brunson Lk., VI.25.61 (G.G.E. S c u d d e r ) ; •3 Nymphs, B r i t i s h C o l u m b i a : S p r i n g h o u s e Lk., V I I . 4 . 6 3 (G.G.E. S c u d d e r ) ; 1 Nymph, B r i t i s h C o l u m b i a : P a v i l i o n , VI.30.61 (G.G.E. S c u d d e r ) ; -122-,3 Nymphs, B r i t i s h C o l u m b i a : W i l l i a m s L ake, VI.24.61 (G.G.E. S c u d d e r ) ; 41 Nymphs, B r i t i s h C o l u m b i a : Q u e s n e l , VI.24.61 (G.G.E. S c u d d e r ) . B a e t i s s p . 5  A d u l t : Unknown Nymph: F r o n t o f head l i g h t brown; wing pads l i g h t brown; abdominal t e r g i t e s brown, p a t t e r n e d w i t h d a r k e r brown; t e r g i t e s 5,6, 9 and 10 may be p a l e r ; each t e r g i t e w i t h a p a i r o f p a l e s u b l a t e r a l l i n e s ; p a t t e r n on each of t e r g i t e s 7 and 8 i s a dark median t r i a n g l e , apex d i r e c t e d a n t e r i o r l y , and a dark s p o t on each s i d e of the apex; t e r g i t e s 9 and 10 each w i t h a dark m e d i a l l i n e ; t a i l s 3, m i d d l e t a i l 5/6 the l e n g t h o f t h e l a t e r a l t a i l s . D i s t r i b u t i o n : B r i t i s h C o l umbia M a t e r i a l Examined: 1 Nymph, B r i t i s h C o l u m b i a : Uiarmspring Lk., VII.15.62 (G.G.E. . S c u d d e r ) ; the a u t h o r has a l s o examined many o t h e r nymphs of t h i s s p e c i e s t a k e n by Dr. G.G.E. Scudder, from IV.4.59 t o IX.23.63 a t the f o l l o w i n g l o c a t i o n s : B r i t i s h C olumbia - Rock Lk., S p r i n g -house Lk., B o i t a n o Lk., R i s k e C r . , R a c e t r a c k Lk., n r . P h a l e r o p e , Q u e s n e l , Ulestwick Lk., F e l k e r Lk., M c l n t y r e Lk., Brunson Lk., White Lk., N i c o l C r . , Dougout Lk., P a v i l i o n , Sorenson Lk., W i l l i a m s Lk., P h a l e r o p e Lk., Beaver Lk. B a e t i s s p . 6  A d u l t : Unknown Nymph: Wing pads may be l i g h t or dark brown; g i l l s l a r g e ; t r a c h e a t i o n d i s t i n c t ; abdominal t e r g i t e s brown, 8-10 p a l e r ; each t e r g i t e w i t h a p a i r o f p a l e s u b l a t e r a l s t r i p e s ; t e r g i t e s 8 t o 10 each w i t h a m e d i a l -123- ' and 2 l a t e r a l dark bands; t a i l s 3, m i d d l e t a i l 5/6 the l e n g t h o f t h e l a t e r a l s ' . D i s t r i b u t i o n ; B r i t i s h C olumbia M a t e r i a l Examined: 1 Nymph, B r i t i s h C o l u m b i a : N i c o l a L ake, 59 Nymphs, B r i t i s h C o l u m b i a : S p r i n g h o u s e Lk., V.5.63 (G.G.E. S c u d d e r ) . B a e t i s s p . 7  A d u l t : Unknown Nymph: G i l l s l a r g e ; t r a c h e a t i o n d i s t i n c t ; abdominal t e r g i t e s u n i c o l o u r e d ; t a i l s 3, m i d d l e t a i l l / 2 the l e n g t h of the l a t e r a l s . D i s t r i b u t i o n : B r i t i s h C olumbia M a t e r i a l Examined: 1 Nymph, B r i t i s h C o l u m b i a : R a c e t r a c k Lake, VI.21.61 (G.G.E. S c u d d e r ) . GENUS CALLIBAETIS EATON C a l l i b a e t i s , Needham, 1935, The B i o l o g y of M a y f l i e s , 657 ( B i b l i o g r a p h y ) A d u l t : S m a l l t o medium s i z e d m a y f l i e s ; b o d i e s and u s u a l l y l e g s t h i c k l y s p r i n k l e d w i t h s m a l l r e d d i s h or dark brown s p o t s , o f t e n a p p e a r i n g t o be s e t i n s m a l l d e p r e s s i o n s ; males u s u a l l y d a r k e r i n c o l o u r than the f e m a l e s ; t u r b i n a t e eyes of male m o d e r a t e l y l a r g e , l e n g t h i l y o v a l ; eyes o f female l a r g e , not s e t h i g h on the s i d e of the head; p o s t e r i o r margin of head of female s l i g h t l y e m a r g i n a t e m e d i a l l y , on each s i d e of which i s a p o s t e r i o r l y d i r e c t e d s l i g h t l y rounded l o b e ; f o r e l e g o f male s l i g h t l y s h o r t e r than the body; femur about 3/4 the l e n g t h of the t i b i a , which i s s l i g h t l y s h o r t e r or s u b e q u a l t o t a r s u s ; 1 s t j o i n t o f t a r s u s e q u a l t o j o i n t s 3 and 4; i n f o r e l e g of f e m a l e , femur -124-s u b e q u a l to t i b i a , which i s s l i g h t l y s h o r t e r than the t a r s u s ; h i n d t i b i a o f both sexes l / 2 t o 3/4 the l e n g t h of the femur, t a r s u s s l i g h t l y s h o r t e r than the t i b i a ; f o r e w i n g of f e m a l e u s u a l l y ornamented w i t h b r o w n i s h a l o n g the c o s t a l m a r g i n , and sometimes i n the d i s c ; f o r e -wing o f male may be w h o l l y h y a l i n e , o r w i t h some dark c o l o u r , but l e s s t h a n i n the f e m a l e ; f o r e w i n g u s u a l l y w i t h numerous c o s t a l c r o s s -v e i n s b e f o r e the b u l l a ; o t h e r c r o s s v e i n s u s u a l l y numerous, a l t h o u g h they may be few i n number i n some s p e c i e s ; m a r g i n a l i n t e r c a l a r i e s o c c u r r i n g s i n g l y or i n p a i r s , the number not c o n s t a n t w i t h i n any one s p e c i e s ; u s u a l l y , the i n t e r c a l a r i e s a t the t i p and i n the a n a l r e g i o n are p a i r e d , w h i l e the r e s t may be s i n g l e ; h i n d wing r e l a t i v e l y l a r g e , widened a t base; c o s t a l p r o j e c t i o n l a r g e and v e r y o b t u s e ; t h r e e l o n g i t u d i n a l v e i n s ; s e v e r a l w e l l - d e v e l o p e d ' c r o s s v e i n s , e s p e c i a l l y i n the c o s t a l r e g i o n ; a few i n t e r c a l a r i e s p r e s e n t between v e i n s 2 and 3; f o r c e p s 4 - j o i n t e d ; a s m a l l rounded or c o n i c a l " p e n i s c o v e r " i s p r e s e n t between the f o r c e p s b a s e s ; p o s t e r i o r margin of s t e r n i t e 9 o f f e m a l e a l m o s t s t r a i g h t . Nymph; M a x i l l a r y p a l p t w o - j o i n t e d ; c a n i n e s of m a n d i b l e s l o n g and s l e n d e r ; l a b i a l p a l p ' 3 - j o i n t e d , the d i s t a l j o i n t s h o r t and c o n i c a l ; c l a w s l o n g and s l e n d e r , 1/-2 t o 3/4 the l e n g t h of t h e t a r s u s , and d e n t i c u l a t e ; 2 p a i r s of wing buds p r e s e n t ; g i l l s l a r g e , i r r e g u l a r l y s u b o v a t e , p o i n t e d a t t i p ; g i l l s d ouble on segments 1-6 or 1-7, o r the v e n t r a l p o r t i o n b e i n g a s m a l l r e c u r v e d f l a p ; the v e n t r a l f l a p on segments 1 and 2 w e l l d e v e l o p e d , may bear a s m a l l s e c o n d a r y f l a p ; t r a c h e a t i o n p i n n a t e o r p a l m a t e , or s i m p l e on the o u t e r m a r g i n ; t a i l s t h r e e , a l l e q u a l i n l e n g t h and t h i c k n e s s . Genotype: C a l l i b a e t i s p i c t u s ( i n B a e t i s ) Eaton -125-CALLIBAETIS  Key To A d u l t s 1. M a r g i n a l i n t e r c a l a r i e s s i n g l e i n f e m a l e , b a r e l y v i s i b l e . c a r o l u s T r a v e r M a r g i n a l i n t e r c a l a r i e s p a i r e d o.2. 2. U i t t a not p a t t e r n e d i n brown or b l a c k . 3. V i t t a p a t t e r n e d i n brown or b l a c k . . . 5. 3. L o n g i t u d i n a l v e i n s a l t e r n a t e l y l i g h t and dark sp. 1 L o n g i t u d i n a l v e i n s c o m p l e t e l y p a l e 4. 4. C o l o u r i n g dark. F i n e c r o s s v e i n s between Rs and Of of f o r e w i n g . . . . s p . 2 C o l o u r i n g l i g h t e r . More th a n f i v e c r o s s v e i n s between Rs and Of o f f o r e w i n g sp. 5 5. L o n g i t u d i n a l v e i n s c o m p l e t e l y p a l e sp. 3 L o n g i t u d i n a l v e i n s a l t e r n a t e l y l i g h t and d a r k . . 6 6. L a t e r a l a r e a s of mesonotum y e l l o w sp. 4 L a t e r a l a r e a s of mesonotum not p a l e r than r e s t of mesonotum.....7. 7. Abdominal t e r g i t e s u n i c o l o u r e d 8. Abdominal t e r g i t e s w i t h dark or p a l e l o n g i t u d i n a l s t r i p e s . . 10. 8. Abdomen dark brown, alm o s t b l a c k i s h . . . . c o l o r a d e n s i s Banks Abdomen r e d d i s h brown 9. 9. Wings o f male a l m o s t c l e a r w i t h two narrow widened brown p o r t i o n s on the c o s t a , s t i g m a s l i g h t l y b r o w n - t i n g e d . V i t t a of female wide, dark brown, i t s h i n d margin w i t h about 5 l o b e s . . . . . . . . . h a q e n i ( E a t o n ) U i t t a wide, i t s h i n d margin w i t h 4 l o b e s . Many h y a l i n e s p o t s i n c o s t a l c e l l .sp.7 -126-10. T e r g i t e s w i t h a dark "median s t r i p e ( p a l e i n the m i d d l e i n the l a s t few segments) n i q r i t u s Banks T e r g i t e s w i t h a l i g h t median and 2 l i g h t submedian s t r i p e s . . s p . 6 Key To Nymphs 1. Femur w i t h a broad p r e - a p i c a l band • .haqeni ( E a t o n ) No such band on femur sp.8 Unknown; C a l l i b a e t i s c o l o r a d e n s i s Banks C a l l i b a e t i s n i q r i t u s Banks C a l l i b a e t i s c a r o l u s T r a v e r CALLIBAETIS CAROLUS TRAVER C a l l i b a e t i s c a r o l u s T r a v e r , Edmunds and A l l e n , 1957, Ann. E n t . Soc. Amer. 50 (4) : 320 ( B i b l i o g r a p h y ) A d u l t : A brown m a y f l y ; t u r b i n a t e eyes of male orange-brown; t h o r a c i c notum of male red-brown; t h o r a c i c notum of female y e l l o w i s h ; p o s t e r o -l a t e r a l margins of mesonotum dark red-brown; i n the male, the f o r e l e g i s b r o w n i s h ; the femora may be y e l l o w i s h b a s a l l y , t a r s i p a l e , or the e n t i r e l e g may be smoky to p a l e red-brown, the femur w i t h a d i s t i n c t p r e - a p i c a l dark band; m i d d l e and h i n d l e g s w h i t i s h o r y e l l o w i s h w h i t e , f a i n t dark band near apex of femur and o c c a s i o n a l l o n g i t u d i n a l dark s t r e a k s ; s t i p p l i n g , i f p r e s e n t , very f a i n t ; t a r s i shaded w i t h l i g h t brown; i n f e m a l e , l e g s w h i t i s h or y e l l o w i s h ; t a r s i u s u a l l y brown; femora u s u a l l y w i t h some r e d d i s h brown s t i p p l i n g ; wings h y a l i n e , i r r i d e s c e n t ; more than 35 c r o s s v e i n s ; i n male m a r g i n a l i n t e r c a l a r i e s u s u a l l y p a i r e d ; l o n g i t u d i n a l v e i n s a l t e r n a t e l y brown and p a l e ; c r o s s v e i n s p a l e ; o u t e r margins brown; u s u a l l y f a i n t b l a c k i s h -brown m a r k i n g s a l o n g the c o s t a ; extreme a p i c a l p o r t i o n o f c o s t a l -127-space shaded w i t h brown; m a r g i n a l i n t e r c a l a r i e s of female o f t e n s i n g l e , may be b a r e l y v i s i b l e ; v i t t a b l a c k i s h brown e x c e p t basad o f - c o s t a l b r a c e ; v i t t a narrow, s i n u a t e i n i t s p o s t e r i o r m a r g i n , e x t e n d i n g i n t o 4 d i s t i n c t l o b e s , the most a p i c a l of which has 3 or more s m a l l secondary l o b e s ; c o s t a l space i n t e r r u p t e d brown-and w h i t e ; c r o s s v e i n s i n v i t t a f e n e s t r a t e w i t h h y a l i n e ; c o s t a l b r a c e brown on each end and pale" i n - t h e m i d d l e , and on each s i d e near Sc i s a brown c l o u d ; s m a l l dark c l o u d s a l o n g l o n g i t u d i n a l v e i n s , and some on the p o s t e r i o r m a r g i n ; l o n g i t u d i n a l v e i n s as i n male; abdominal t e r g i t e s of male dark red-brown, p o s t e r i o r m argins deeper; each t e r g i t e w i t h two dark submedian l i n e s , u s u a l l y s e p a r a t e d by a narrow p a l e median l i n e , and f l a n k e d by 2 p a l e r y e l l o w -i s h s t r e a k s ; dark l i n e a l o n g p l e u r a l f o l d ; s t i p p l i n g m o d e r a t e l y dense and r e g u l a r ; s t e r n i t e s p a l e r y e l l o w i s h - brown, w i t h dark submedian s t r e a k s ; s t i p p l i n g f i n e r ; a p i c a l s t e r n i t e s o f t e n opaque creamy o r y e l l o w i s h w h i t e ; abdomen of female s i m i l a r , but p a l e r ; f o r c e p s and t a i l s p a l e , j o i n i n g s n a r r o w l y b l a c k i s h . Nymph; Unknown D i s t r i b u t i o n : C a l i f o r n i a , B r i t i s h C olumbia M a t e r i a l Examined:. 1 Female, B r i t i s h C o l u m b i a : Vernon, VII.26.63 (G.G.E. Scudder) 2 Females, B r i t i s h C o l u m b i a : L y t t o n , V I I I . 3 0 . 3 1 ( G . J . S p e n c e r ) , 1 Female, B r i t i s h C o l u m b i a , Vernon, VII.10.48 (D. E v a n s ) . CALLIBAETIS C0L0RADENSIS BANKS C a l l i b a e t i s c o l o r a d e n s i s Banks, Needham, 1935, The B i o l o g y o f May-f l i e s , 664 ( B i b l i o g r a p h y ) A d u l t : ( f e m a l e ) A dark brown m a y f l y ; t h o r a x dark brown; femora f i n e l y s t i p p l e d -128-u i i t h brown; t i p s of t a r s i brown; c r o s s v e i n s of f o r e w i n g b e h i n d the v i t t a more than 35, u s u a l l y s e v e r a l c l o s e to h i n d m a r g i n , a r r a n g e d i n 2 or more i r r e g u l a r rows a c r o s s the wing; most c r o s s v e i n s w h i t e ; m a r g i n a l i n t e r c a l a r i e s u s u a l l y p a i r e d ; v i t t a dark brown, broken up i n t o t h r e e main s p o t s , one a p i c a l , one s t i g m a t i c , and one b e f o r e the m i d d l e , w i t h a s m a l l e r one a t base; b a s a l c o s t a l space h y a l i n e ; l o n g i t u d i n a l v e i n s brown i n p l a c e s , or a l t e r n a t e l y l i g h t and d a r k ; no c l o u d s on v e i n s ; h i n d wing l o n g and narrow; c o s t a l margin somewhat • e m a r g i n a t e b e h i n d the c o s t a l p r o j e c t i o n ; m a r g i n a l i n t e r c a l a r i e s v e r y l o n g , r e s e m b l i n g l o n g i t u d i n a l v e i n s , and 3 or 4 i n number; c r o s s -v e i n s t e n d t o be a r r a n g e d i n groups of 2; abdomen b l a c k i s h brown, r e l a t i v e l y s h o r t . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h C o l u m b i a , C o l o r a d o No specimens of t h i s s p e c i e s were examined. CALLIBAETIS HAGENI (EATGN) C a l l i b a e t i s h a q e n i ( E a t o n ) , Needham, 1935, The B i o l o g y o f M a y f l i e s , 668 ( B i b l i o g r a p h y ) A d u l t : (Female) A p i c e o u s s p e c i e s ; d o r s a l s u t u r e s of notum y e l l o w i s h ; d a r k e r , p o l i s h e d i n male; l e g s brown i n both s e x e s , femora d e n s e l y , f i n e l y , and i n c o n s p i c u o u s l y s p e c k l e d ; more th a n 35 c r o s s v e i n s b e h i n d the v i t t a o f the f o r e w i n g , u s u a l l y s e v e r a l c l o s e to the h i n d m a r g i n , and a r r a n g e d i n 2 or more i r r e g u l a r rows a c r o s s the wing; c r o s s v e i n s m o s t l y w h i t e ; m a r g i n a l i n t e r c a l a r i e s m o s t l y p a i r e d , a few s i n g l e ; v i t t a o f female dark brown, wide, e x t e n d i n g i n i t s p o s t e r i o r margin -129-i n t o 5 l o b e s ; the second b e i n g the l a r g e s t ; b a s a l c o s t a l space i n -c l u d e d i n v i t t a ; b e h i n d the v i t t a , a l o n g the l o n g i t u d i n a l v e i n s , are 3 rows of brown s p o t s , the m i d d l e one b e i n g the l a r g e s t , l o n g i t u d i n a l v e i n s i n t e r r u p t e d brown and w h i t e , as i s the o u t e r margin of the wing; i n t e r c a l a r i e s brown, sometimes i n a f a i n t b r o w n i s h c l o u d ; e r o s s v e i n s i n the v i t t a f e n e s t r a t e w i t h h y a l i n e ; s t i g m a t i c c r o s s v e i n s few " i n number, a s l a n t , f e n e s t r a t e , l e s s so and f a i n t i n male; c l o u d s on c r o s s v e i n s ; wing of male a l m o s t c l e a r , w i t h 2 brown widened p o r t i o n s on the c a s t a ; s t i g m a s l i g h t l y b r o w n - t i n g e d ; abdomen deep r e d d i s h brown; a l m o s t b l a c k i s h d o r s a l l y , p a l e r v e n t r a l l y ; t h i c k l y s t i p p l e d ; t a i l s w h i t e , j o i n i n g s b l a c k . Nymph: Femur w i t h a broad p r e - a p i c a l band; t a i l s w h o l l y p a l e , or w i t h a narrow dark band near t i p o n l y . D i s t r i b u t i o n : Oregon, C o l o r a d o , C a l i f o r n i a , Wyoming, Montana, Washington, New York, B r i t i s h C o l u m b i a . No specimens of t h i s s p e c i e s were examined. CALLIBAETIS NIGRITUS BANKS C a l l i b a e t i s n i q r i t u s Banks, Needham, 1935, The B i o l o g y of M a y f l i e s , 669 ( B i b l i o g r a p h y ) A d u l t : (Male) A dark brown m a y f l y ; t h o r a c i c notum b l a c k i s h ; f o r e l e g s b l a c k i s h ; m i d d l e and h i n d l e g s p a l e , femora d a r k e r b e f o r e apex, t a r s i d a r k e r ; femora f i n e l y and r e g u l a r l y s t i p p l e d ; c r o s s v e i n s of f o r e w i n g b e h i n d • v i t t a more than 35, u s u a l l y s e v e r a l c l o s e to h i n d m a r g i n , a r r a n g e d i n 2 or more r e g u l a r rows a c r o s s the wing; i n t e r c a l a r i e s m o s t l y i n p a i r s ; -130-wings h y a l i n e ; l o n g i t u d i n a l v e i n s a l t e r n a t e l y w h i t e and b l a c k ; c r o s s -v e i n s m o s t l y p a l e ; o u t e r margin a l t e r n a t e l y dark and p a l e ; c o s t a l a r e a marked w i t h b l a c k s p o t s , w i t h v a r i o u s d o t s on c o s t a l m a r g i n , and s t r e a k s and do t s a l o n g v e i n s and beyond the m i d d l e , two b e i n g l a r g e r t h a n the o t h e r s ; abdominal t e r g i t e s w i t h a d a r k e r median s t r i p e which i s p a l e i n the m i d d l e on the a p i c a l segments; s t e r n i t e s w i t h a p a i r of dark submedian s t r i p e s ; f o r c e p s and t a i l y e l l o w i s h . Nymph: Unknown D i s t r i b u t i o n : C o l o r a d o , B r i t i s h Columbia M a t e r i a l Examined: 3 Male, B r i t i s h C o l u m b i a : C h i l c o t i n , V.28.63 (G.G.E. S c u d d e r ) ; 1 Male, B r i t i s h C o l u m b i a : S p r i n g h o u s e Lake ( C a r i b o o ) V.25.63 (G.G.E. S c u d d e r ) ; 1 Male, B r i t i s h C o l u m b i a : C h i l c o t i n , VI.17.63 (G.G.E. S c u d d e r ) . C a l l i b a e t i s s p . 1  A d u l t : (Male) L a t e r a l a r e a s of mesonotum y e l l o w ; l e g s y e l l o w i s h - r e d ; more than 35 c r o s s v e i n s i n f o r e w i n g ; m a r g i n a l i n t e r c a l a r i e s p a i r e d ; no dark v i t t a ; l o n g i t u d i n a l v e i n s a l t e r n a t e l y l i g h t and d s r k , s t r o n g l y so i n c o s t a l v e i n s ; no c l o u d s on wings; abdominal t e r g i t e s dark r e d d i s h -brown; v e n t e r p a l e and l i g h t l y s t i p p l i e d ; t a i l s and g e n i t a l i a p a l e . Nymph: Unknown. D i s t r i b u t i o n : B r i t i s h Cciimbia M a t e r i a l Examined: 1 Male, B r i t i s h C o l u m b i a : L y t t o n , V I I I . 9 . 3 1 (G.3. S p e n c e r ) . -131-C a l l i b a e t i s sp.. 2  A d u l t : (fflale) T h i s s p e c i e s e x a c t l y r e s s e m b l e s C a l l i b a e t i s sp. 1, w i t h the d i f f e r e n c e t h a t t h e r e i s a b s o l u t e l y no p i g m e n t a t i o n i n the wing membrance or v e n a t i o n ; t h e r e are 5 c r o s s v e i n s between the Of and Rs of the f o r e w i n g . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h C o l u m b i a M a t e r i a l Examined: 1 Male, B r i t i s h C o l u m b i a : L y t t o n , V I I I . 9 . 3 1 (G.3. S p e n c e r ) , 1 M a l e , B r i t i s h C o l u m b i a : Q u e s n e l , V I I I . 1 2 . 4 8 (H.R. M c C a r t h y ) , 1 Male, B r i t i s h C o l u m b i a : N i c o l a , V I I I . 3 0 . 2 5 ( G . J . S p e n c e r ) 1 M a l e , B r i t i s h C o l u m b i a : Nanaimo, V I I . 1 9 . 6 1 (G.G.E. S c u d d e r ) . C a l l i b a e t i s s p . 3  A d u l t : (fflale) Very s i m i l a r t o C a l l i b a e t i s s p . 1, mesonotum r e d d i s h brown; c r o s s v e i n s o f f o r e w i n g more numerous than i n C a l l i b a e t i s s p . 1; l o n g i t u d i n a l v e i n s not a l t e r n a t e l y l i g h t and d a r k ; v i t t a c o n s i s t i n g of a l t e r n a t e l y l i g h t and dark a r e a s ; s t i g m a t i c a r e a y e l l o w i s h . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: '. . 1 fflale, B r i t i s h C o l u m b i a : P a v i l i o n fflt., VI.27.43 (G.3. S p e n c e r ) , 1 fflale, B r i t i s h C o l u m b i a : Q u e s n e l , VI.3.48 (G.3. S p e n c e r ) . -132-C a l l i b a e t i s sp. 4_ A d u l t ( m a l e ) : L a t e r a l a r e a s o f mesonotum y e l l o w ; l e g s y e l l o w ; more than 35 c r o s s v e i n s i n f o r e w i n g ; m a r g i n a l i n t e r c a l a r i e s p a i r e d ; l o n g i t u d i n a l v e i n s a l t e r n a t e l y l i g h t and dark; v i t t a wide, e x t e n d i n g on p o s t e r i o r m a r g i n i n t o 4 l o b e s ; many h y a l i n e s p o t s i n c o s t a l c e l l ; no c l o u d s on w i n g s ; abodminal markings much as i n C a l l i b a e t i s n i q r i t u s ; t a i l s p a l e , j o i n i n g s d a r k . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia m a t e r i a l Examined: 1 M a l e , B r i t i s h C o l u m b i a : P a v i l i o n fflt., VI.27.43 ( G . J . Sp e n c e r ) C a l l i b a e t i s sp. 5  A d u l t : ( m a l e ) T h i s s p e c i e s i s s i m i l a r t o C a l l i b a e t i s s p . 2, but l i g h t e r i n c o l o u r ; more th a n 5 c r o s s v e i n s between Rs and Of of f o r e w i n g . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia m a t e r i a l Examined: 6 males, B r i t i s h C o l u m b i a : Kamloops, V I I I . 4 . 3 4 , ( G . J . S p e n c e r ) , 2 males, B r i t i s h C o l u m b i a : N i c o l a , V I I I . 3 0 . 2 5 ( G . J . S p e n c e r ) , 1 male, B r i t i s h C o l u m b i a : Q u e s n e l , VII.23.48 ( G . J . S p e n c e r ) , 1 male, B r i t i s h C o l u mbia: Q u e s n e l , V I I I . 1 2 . 4 8 (H.R. lYlcCarthy), 2 males, B r i t i s h C o l u m b i a : Okanagan Lake, VII.25.35 ( J . L . McHugh), 3 fflales, B r i t i s h C o l u m b i a : N i c o l a , V I I I . 2 1 . 3 2 ( G . J . S p e n c e r ) . C a l l i b a e t i s sp. 6  A d u l t : (fflale) A s p e c i e s v e r y s i m i l a r to C a l l i b a e t i s sp. 4; l a t e r a l a r e a s o f . -133-mesonotum brown; l e g s and t a i l s b r o w n i s h y e l l o w ; abdominal markings d a r k e r than i n C a l l i b a e t i s sp. 4, w i t h each t e r g i t e h a v i n g a median and 2 submedian p a l e s t r e a k s . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h C o lumbia M a t e r i a l Examined: 1 M a l e , B r i t i s h C o l u m b i a : B l a n k e t Mt., V I I I . 1 . 4 6 C a l l i b a e t i s s p . 7  A d u l t : (Female) C l o s e l y r e s e m b l i n g C a l l i b a e t i s s p . 4, but abdominal t e r g i t e s and s t e r n i t e s r e d d i s h brown; mesonotum a l l brown; l e g s brown; a l a r g e r s p e c i e s . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: 1 Female, B r i t i s h C o l u m b i a : N i c o l a , UII..10.32 (G.3. S p e n c e r ) C a l l i b a e t i s sp. 8  A d u l t : Unknown Nymph:-No p r e - a p i c a l band on femur; g i l l s on segments 1-7 l a r g e , h e a v i l y t r a c h e a t e d ; no l i g h t s p o t s on t e r g i t e s ; t a i l s h e a v i l y f r i n g e d , dark a t t i p s . E c o l o g y : Specimens of t h i s s p e c i e s were t a k e n from the edges o n l y o f the A l o u e t t e R i v e r . The s u b s t r a t e was mud, s i l t , and i n one c a s e , sand and . g r a v e l . They,were t a k e n at a depth of 1-4 f e e t , i n q u i e t , slow w a t e r , a l t h o u g h i n one case (from.sand and g r a v e l ) , the c u r r e n t -134-produced r i p p l e s . A l l specimens were c o l l e c t e d on J u l y 1, 1959, and were found a t not any o t h e r t i m e . D i s t r i b u t i o n ; B r i t i s h Columbia M a t e r i a l Examined: 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney,.B.C.) VII.1,59 ( N . J . F i l m e r ) GENUS CENTROPTILUM EATON C e n t r o p t i l u m , Needham, 1935, The B i o l o g y of M a y f l i e s , 705 ( B i b l i o g r a p h y ) A d u l t ; S m a l l , p a l e m a y f l i e s ; t u r b i n a t e eyes of male moderate t o l a r g e , - u s u a l l y j b n g t h i l y o v a l ; eyes o f female l a r g e , s e t h i g h on the s i d e s o f the head; p o s t e r i o r margin of head of female d i s t i n c t l y e m a r g i nate m e d i a l l y ; f o r e l e g o f male as l o n g as body; f o r e femur l / 2 to 2/3 the l e n g t h o f the t i b i a , w hich i s s l i g h t l y s h o r t e r t h a n the t a r s u s ; i n f e m a l e , f o r e femur s l i g h t l y l o n g e r than the 1 t i b i a , w h i c h i s a l i t t l e l o n g e r than the t a r s u s ; f i r s t j o i n t o f t a r s u s e q u a l t o j o i n t s 2, 3 and 4 i n h i n d l e g of both s e x e s ; t a r s u s , t i b i a , and femur sub-e q u a l ; m a r g i n a l i n t e r c a l a r i e s o f f o r e w i n g o c c u r s i n g l y ; no c o s t a l c r o s s v e i n s b e f o r e the b u l l a ; h i n d wing s m a l l , narrow, and e l o n g a t e ; c o s t a l p r o j e c t i o n c u r v e d ; two l o n g i t u d i n a l v e i n s ; c r o s s v e i n s absent or few; b a s a l abdominal segments of male u s u a l l y p a l e y e l l o w i s h o r w h i t i s h , o f t e n w i t h e x t e n s i v e ruddy or brow n i s h m a r k i n g s ; f e m a l e s p a l e r , o f t e n l i g h t r e d d i s h - b r o w n ; b a s a l f o r c e p s j o i n t s wide a p a r t , s t o u t , u s u a l l y s l i g h t l y w i d e r than l o n g ; second j o i n t s t o u t , o f t e n - p r o l o n g e d i n w a r d on i t s o u t e r margin; t h i r d j o i n t l o n g and s l e n d e r , f r e q u e n t l y bowed; d i s t a l j o i n t sometimes h a l f as l o n g as t h i r d j o i n t , u s u a l l y s h o r t e r , c l a v a t e , 2 or 3 t i m e s as l o n g as wide; a l a r g e -135-" p e n i s c o v e r " between b a s a l j o i n t s ; p o s t e r i o r margin o f 9 t h s t e r n i t e o f female p r o l o n g e d backwards ve r y s l i g h t l y m e d i a l l y . Nymph; M a x i l l a r y p a l p 3 - j o i n t e d , e x t e n d i n g beyond the t i p of the g a l e a -l a c i n i a ; c a n i n e s o f m a n d i b l e s l o n g , s l e n d e r , a n d s h a r p - p o i n t e d , or s h o r t e r and s t o u t e r ; l a b i a l p a l p 3 - j o i n t e d , d i s t a l j o i n t d i l a t e d and t r u n c a t e a p i c a l l y ; c l a w s l o n g and s l e n d e r l / 2 t o 3/4 t h e l e n g t h o f the t a r s i , not d e n t i c u l a t e ; 2 p a i r s o f wing buds; g i l l s u s u a l l y s i n g l e , may be double on segments 1-6, the second p o r t i o n c o n s i s t i n g of a s m a l l r e c u r v e d d o r s a l f l a p ; t r a c h e a t i o n p i n n a t e , may be on i n n e r s i d e o n l y ; t a i l s t h r e e , a p p r o x i m a t e l y e q u a l i n l e n g t h and t h i c k n e s s . Genotype; C e n t r o p t i l u m l u t e o l u m ( i n Ephemera) M u l l e r CENTROPTILUM  Key To A d u l t s 1. Abdominal t e r g i t e s 7-10 opaque creamy w h i t i s h . I n n e r margin of second f o r c e p s j o i n t w i t h a p o o r l y d e v e l o p e d t u b e r c l e . Eyes orange brown. Mesothorax y e l l o w brown........album McD Abdominal t e r g i t e s 7-10 not w h i t i s h . Inner margin o f f o r c e p s j o i n t w i t h a d i s t i n c t t u b e r c l e on i n w a r d b u l g e . 2. 2. I n n e r margin of second f o r c e p s j o i n t d i s t i n c t l y and p r o m i n e n t l y t u b e r c u l a t e . D i s t a l j o i n t o f f o r c e p s v e r y l o n g . Eyes b l a c k -brown. Mesothorax b l a c k . Abdominal t e r g i t e s 2 - 6 h y a l i n e w h i t e . conturbatum McD Inner margin o f second j o i n t of f o r c e p s may p o s s e s s a d i s t i n c t i n w a r d b u l g e , but i s not t u b e r c u l a t e . D i s t a l j o i n t of f o r c e p s i s s h o r t e r , ^yes not b l a c k - b r o w n . Mesothorax not b l a c k . Abdominal t e r g i t e s 2-6 not h y a l i n e w h i t e 3. -136-3. A d i s t i n c t t u b e r c l e i s p r e s e n t between the bases of the f o r c e p s l i m b s . T e r g i t e s 2-4 w i t h narrow ruddy p o s t e r i o r m a r g i n s , 7-9 c h o c o l a t e brown, 10 y e l l o w i s h , flflesothorax deep o l i v e brown. Eyes orange-brown b i f u r c a t u m HflcD No t u b e r c l e between the bases of the f o r c e p s l i m b s . LUedge shaped ruddy l a t e r a l m a rkings on t e r g i t es 2—6, 7—10 red-brown, fflesothorax o l i v a c e o u s . Eyes r e d . b e l l u m fflcD Key To Nymphs 1. G i l l s s i n g l e on a l l segments 2. G i l l s double on some or a l l segments...... 3. 2. Abdominal segments 7-10 l a r g e l y shaded w i t h brown. L a t e r a l edges of a l l t e r g i t e s p a l e , w i t h a brown t r a n s v e r s e band on each. G i l l t r a c h e a t i o n q u i t e d i s t i n c t , u s u a l l y p i n n a t e . . . . album McD Abdominal t e r g i t e s brown, p a t t e r n e d w i t h 3 p a l e s p o t s on each. T e r g i t e s 7 and 10 l a r g e l y p a l e . G i l l s t r a c h e a t i o n not d i s t i n c t sp. 1 3. G i l l s d ouble on segments 1-7. T a i l s w i t h a dark a p i c a l band '.. b e l l u m fflcD G i l l s double, on segments 1-2. No banded t a i l 4. 4. F a i n t p a t t e r n on t e r g i t e s , but p o s t e r i o r b o r d e r s dark brown, .sp. 3 T e r g i t e s u n i c o l o u r e d on l a t e r a l edges l a r g e l y p a l e . . . . . 5. 5. No p a t t e r n on t e r g i t e s sp. 4 Abdominal t e r g i t e s 7-10 l a r g e l y shaded w i t h brown. L a t e r a l edges of a l l t e r g i t e s p a l e , w i t h brown t r a n s v e r s e band on each... sp. 2 -137-Unknown: . C e n t r o p t i l u m b i f u r c a t u m IYlcD C e n t r o p t i l u m conturbatum IYlcD CENTROPTILUM ALBUM McDUNNOUGH  C e n t r o p t i l u m album McDunnough, Needham, 1935, The B i o l o g y of May-f l i e s , 708 ( B i b l i o g r a p h y ) A d u l t ; . T u r b i n a t e eyes orange-brown; mesonotum p a l e ochreous w i t h brown s h a d i n g , s c u t e l l u m and p o s t e r i o r p o r t i o n a l m o s t e n t i r e l y w h i t e w i t h f a i n t p i n k s h a d i n g ; metanoturn deep brown p o s t e r i o r l y , a n t e r i o r margin w h i t e w i t h p i n k i s h s h a d i n g , and a median dark s p o t ; p l e u r a and s t e r n a deep brown; l e g s w h i t e ; wings h y a l i n e ; v e n a t i o n p a l e ; h i n d wing v e r y narrow; c o s t a l p r o j e c t i o n p r o m i n e n t ; abdominal t e r g i t e s h y a l i n e i n male, y e l l o w i s h o r w h i t i s h ; t e r g i t e s 7-10 opaque, creamy w h i t e ; t a i l s w h i t e ; i n w a r d b u l g e o f second f o r c e p s j o i n t s l i g h t . Nymph; G i l l s s i n g l e on segments 1-7 (no r e c u r v e d f l a p ) ; g i l l t r a c h e a t i o n n o r m a l l y p i n n a t e , d i s t i n c t ; abdominal t e r g i t e s 7-10 l a r g e l y shaded w i t h brown. D i s t r i b u t i o n ; B r i t i s h C o l u m b i a , Eastern N o r t h America No specimens o f t h i s s p e c i e s were examined. CENTROPTILUM BELLUM McDUNNOUGH C e n t r o p t i l u m b e l l u m McDunnough, Needham, 1935, The B i o l o g y of May-f l i e s , 709 ( B i b l i o g r a p h y ) A d u l t : T u r b i n a t e eyes deep r e d d i s h ; mesonotum o l i v a c e o u s shaded w i t h y e l l o w i s h s u b d o r s a l l y ; l a t e r a l and p o s t e r i o r margins t i n g e d w i t h -138-ruddy; metanotum deep o.live ..brown, s u t u r e s d a r k e r , a n t e r i o r d o r s a l p o r t i o n shaded w i t h ruddy; l e g s y e l l o w i s h w h i t e ; wings h y a l i n e ; h i n d wing m o d e r a t e l y b r o a d ; two l o n g i t u d i n a l v e i n s ; abdominal t e r g i t e s 2-6 s e m i - h y a l i n e , p a l e y e l l o w i s h , the p o s t e r i o r margins n a r r o w l y ruddy brown e n d i n g i n f a i n t s m a l l r e d d i s h p a t c h e s i n the s p i r a c u l a r a r e a ; t e r g i t e s 7-10 b r i g h t ruddy brown; s t e r n i t e s 2-6 p a l e ; s t e r n i t e s 7-10 opaque y e l l o w i s h shaded l a t e r a l l y w i t h r e d d i s h and w i t h f a i n t ruddy p o s t e r i o r m a r g i n s ; s p i r a c u l a r l i n e b l a c k i s h ; f o r c e p s and t a i l s w h i t e . Nymph; G i l l s double on a l l segments; abdominal t e r g i t e s marked w i t h brown; t e r g i t e s 4, 5, 7, 8, and 10 p a l e r ; , t a i l s dark i n a p i c a l l / 3 . D i s t r i b u t i o n - : B r i t i s h C o lumbia, Quebec. M a t e r i a l Examined: 1 Nymph, B r i t i s h C o l u m b i a : W i l l i a m s Lake, V I . 2 4 i 6 1 (G.G.E. Scudder) CENTROPTILUM BIFURCATUM McDUNNOUGH C e n t r o p t i l u m b i f u r c a t u m McDunnouqh, Needham, 1935, T n e B i o l o g y o f M a y f l i e s , 711 ( B i b l i o g r a p h y ) A d u l t : Thorax deep o l i v e brown, mesonotum w i t h a p a l e y e l l o w l i n e e x t e n d -i n g f o r w a r d along each l a t e r a l margin from the wing base, e n d i n g i n a s m a l l round y e l l o w i s h p a t c h , and y e l l o w i s h s u t u r e s and p o s t e r i o r m a r g i n ; l e g s p a l e y e l l o w i s h w h i t e , femora deeper i n c o l o u r ; wings h y a l i n e ; h i n d wing r e l a t i v e l y wide; two l o n g i t u d i n a l v e i n s , the second may be f a i n t l y f o r k e d near i t s apex; abdominal t e r g i t e s 2-6 h y a l i n e , y e l l o w i s h white; t e r g i t e s 2 r4 w i t h a f a i n t r e d d i s h d o r s a l h a i r - l i n e , and t r a c e s of ruddy s h a d i n g on p o s t e r i o r m a r g i n s ; on segments 2-6, s p i r a c u l a r a r e a marked by a broken b l a c k i s h l i n e ; -139-t e r g i t . e s 7-9 deep c h o c o l a t e brown; t e r g i t e 1.0 p a l e y e l l o w i s h ; s t e r n i t e s 7-9 a l a b a s t e r w h i t e ; f o r c e p s and t a i l s w h i t i s h ; p l a t e between f o r c e p s base l a r g e and dome-shaped; b e a r i n g a s m a l l p o i n t e d t u b e r c l e . Nymph: Unknown D i s t r i b u t i o n : Idaho, B r i t i s h Columbia No specimens o f t h i s s p e c i e s were examined. CENTROPTILUIYI CONTURBATUffl McDUNNOUGH C e n t r o p t i l u m conturbatum fflcDunnough, Needham, 1935, The B i o l o g y m a y f l i e s , 712 ( B i b l i o g r a p h y ) A d u l t : T u r b i n a t e eyes dark b l a c k i s h brown; t h o r a x s h i n y b l a c k ; l e g s w h i t e ; wings h y a l i n e ; v e n a t i o n p a l e ; abdominal t e r g i t e s 2-6 and p a r t of 7 h y a l i n e w h i t e , sometimes w i t h f a i n t dusky s h a d i n g p o s t e r -i o r l y on m i d d l e segments; t e r g i t e s 8-10, and o f t e n p a r t of 7, choco-l a t e brown; s t e r n i t e s w h i t e , 2-6 h y a l i n e , 7-10 opaque; t a i l s w h i t e ; i n n e r margin o f second f o r c e p s j o i n t d i s t i n c t l y t u b e r c u l a t e ; t h i r d j o i n t s t r o n g l y bowed; d i s t a l j o i n t u n u s u a l l y l o n g ; p l a t e between f o r c e p s base c o n i c a l on i t s p o s t e r i o r m a r g i n . Nymph: Unknown D i s t r i b u t i o n : Wyoming, C a l i f o r n i a , B r i t i s h C olumbia No specimens of t h i s s p e c i e s were examined. C e n t r o p t i l u m s p . 1 A d u l t : Unknown Nymph: P e c t i n a t e s p i n e s on g a l e a ; g i l l s s i n g l e on segments 1-7, l a r g e ; t r a c h e a t i o n i n d i s t i n c t ; abdominal t e r g i t e s brown, markings v a r i a b l e -140-u s u a l l y 3 p a l e s p o t s on each t e r g i t e , but. t h e r e may be fewer or none; t e r g i t e s 7 and 10, or 7 o n l y , or 1, 2, 6, 7, and 10, may be p a l e ; t a i l s 3, h e a v i l y f r i n g e d ; t a i l s u s u a l l y p a l e w i t h a dark m i d d l e and a p i c a l band or may be e n t i r e l y p a l e . E c o l o g y : T h i s s p e c i e s was t a k e n from the m i d d l e and edges of v a r i o u s l o c a t i o n s on the A l o u e t t e R i v e r , from depths r a n g i n g from 1 t o 5 f e e t , . g e n e r a l l y , however, a t depths of 1 to 2 f e e t . The stream bed v a r i e d from mud, t h r o u g h sand, g r a v e l , r o c k s and b o u l d e r s t o be d r o c k . The c u r r e n t was a l s o v a r i a b l e , from q u i e t , s t i l l w a t e r , to s w i f t r a p i d s . T h i s i s a v e r y p l e n t i f u l and common s p e c i e s . They were t a k e n the y e a r round. D i s t r i b u t i o n ; B r i t i s h Columbia M a t e r i a l Examined; 3 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), V.14.59 (N.3. F i l m e r ) , 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), V I I I . 2 6 . 5 9 (N.3. F i l m e r ) , 2 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), XI.26.59, (N.3. F i l m e r ) . C e n t r o p t i l u m sp. 2  A d u l t : Unknown Nymph: M a x i l l a r y p a l p 2 - j o i n t e d ; s l i g h t s p i n e s on p o s t e r o - l a t e r a l a n g l e s of a b dominal t e r g i t e s ; g i l l s l a r g e , on segments 1-7, d i s t i n c t l y t r a c h e a t e d ; g i l l s on segments 1-2 d o u b l e , r e s t s i n g l e ; l a t e r a l margins of a l l abdominal t e r g i t e s p a l e , each margin w i t h a brown t r a n s v e r s e band; t e r g i t e s 7-10 l a r g e l y shaded w i t h brown; t a i l s 3, e n t i r e l y p a l e . -141-E c o l o q y : T h i s s p e c i e s mas t a k e n from o n l y one l o c a t i o n on the A l o u e t t e R i v e r , from the edge, a t a depth o f 1 t o 2 f e e t . The stream bed c o n s i s t e d of mud and s i l t , w i t h some r o c k s . The water was s t i l l . A l l specimens were t a k e n i n mid-August. D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), V I I I . 1 1 . 5 9 (N.3. F i l m e r ) ; 9 Nymphs, B r i t i s h C o l u m b i a : S p r i n g h o u s e Lake, V I I I . 3 1 . 5 2 (G.G.E. S c u d d e r ) . C e n t r o p t i l u m s p . 3  A d u l t : Unknown Nymph: Both m a n d i b l e s e q u a l i n s i z e ; g i l l s double on segment 1 and 2, s i n g l e on segments 3-7; abdominal t e r g i t e s w i t h a f a i n t p a t t e r n , but p o s t e r i o r b o r d e r s dark brown; t a i l s e n t i r e l y p a l e . D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: 7 Nymphs, B r i t i s h C o l u m b i a : Babine Lake, VII.10.61 (T. N o r t h c o t e ) . C e n t r o p t i l u m sp. 4  A d u l t : Unknown Nymph: M a n d i b l e s e q u a l i n s i z e ; g i l l s double on segments 1 and 2, s i n g l e on segments 3 t o 7; abdominal t e r g i t e s and s t e r n i t e s u n i c o l o u r e d , brown, w i t h no p a t t e r n ; t a i l s 3, e n t i r e l y p a l e . D i s t r i b u t i o n : B r i t i s h Columbia -142-l Y I a t e r i a l Examined: 1 Nymph, 8 r i t i s h C o l u m b i a : S p r i n g h o u s e Lake, V I I I . 1 8 ; 6 2 (G.G.E. S c u d d e r ) , 1 Nymph, B r i t i s h C o l u m b i a : UJestu/ick, VI.1.62 (G.G.E. S c u d d e r ) . GENUS i-NEGCLOEQN TRAVER '•^NaQcloeon, Needham, 1935, The B i o l o g y o f M a y f l i e s , 730 ( B i b l i o g r a p h y ) A d u l t : S m a l l m a y f l i e s ; t u r b i n a t e eyes l a r g e , l e n g t h i l y egg-shaped; eyes o f female l a r g e and s e t h i g h on the s i d e o f the head; p o s t e r i o r margin o f head v e r y s l i g h t l y e m a r g i n a t e ; f o r e l e g of male s l i g h t l y s h o r t e r t h a n the body; femur 3/4 the l e n g t h o f the t i b i a , which i s s u b e q u a l t o the t a r s u s ; i n f e m a l e , femur and t i b i a s u b e q u a l ; t i b i a about 1-1/2 as l o n g as t a r s u s ; i n h i n d l e g of male, femur 1-1/3 t o 1-1/2 t i m e s t h e l e n g t h of the t i b i a , which i s s u b e q u a l to the t a r s u s ; b a s a l t a r s a l j o i n t o f both sexes v e r y l o n g , e q u a l t o o t h e r 3 j o i n t s combined; i n h i n d l e g of f e m a l e , femur al m o s t t w i c e the l e n g t h o f the t i b i a , which i s s l i g h t l y l a r g e r than the t a r s u s ; m a r g i n a l i n t e r c a l a r i e s o f f o r e w i n g s i n g l e ; h i n d wing a b s e n t ; b a s a l j o i n t of f o r c e p s 1-1/3 tim e s as wide as l o n g ; 2nd j o i n t s h o r t and b r o a d , i t s i n n e r margin w i t h a p r o m i n e n t , axe-shaped e x t e n s i o n ; s l i g h t s w e l l i n g near base on i n n e r margin of 3rd j o i n t ; and a more d i s t i n c t s w e l l i n g a p i c a l l y , t h e whole b e i n g s l i g h t l y bowed; d i s t a l j o i n t 2- 1/2 t o 3 t i m e s as l o n g as wide; a p i c a l margin o f s t e r n i t e 9 o f female a l m o s t s t r a i g h t . Nymph: M a x i l l a r y p a l p i 3 - j o i n t e d , e x t e n d i n g w e l l beyond t o t i p o f the g a l e a - l a c i n i a ; c a n i n e s o f m a n d i b l e s l o n g and s l e n d e r ; l a b i a l p a l p i 3- j o i n t e d , d i s t a l j o i n t s w i d e l y d i l a t e d a p i c a l l y ; c l a w s l o n g and -143-s l e n d e r ; almost 3/4 as l o n g as the t a r s i , not d e n t i c u l a t e ; meta-t h o r a c i c wing buds a b s e n t ; g i l l s s i n g l e on segments 1-7; g i l l s a s s y m e t r i c a l l y shaped, s t r a i g h t on a n t e r i o r margin and l o b e d on p o s t e r i o r m a r g i n ; t r a c h e a t i o n p i n n a t e , a l l branches on the p o s t e r i o r s i d e ; t a i l s 3, a p p r o x i m a t e l y e q u a l i n l e n g t h and t h i c k n e s s . Genotype; ..'Neocloeon alamance T r a v e r . '••'Mfi'n'r.loson s p . 1  A d u l t : Unknown Nymph: No p e c t i n a t e s p i n e s on g a l e a ; g i l l s s i n g l e on segments 1-7; a g e n e r a l l y p a l e s p e c i e s ; w i t h abdominal t e r g i t e 7 d a r k ; t a i l s e n t i r e l y p a l e , or w i t h a dark t i p . E c o l o g y ; Specimens o f t h i s s p e c i e s were t a k e n from t h e m i d d l e and edges o f many l o c a t i o n s on the A l o u e t t e R i v e r . The depth v a r i e d from l / 2 t o 5 f e e t , a l t h o u g h u s u a l l y the water was 1 f o o t deep. The stream bed v a r i e d from mud, through sand, g r a v e l , r o c k s , and b o u l d e r s , t o bedrock. The c u r r e n t was g e n e r a l l y s t i l l t o q u i e t r i p p l e s . Specimens were taken from May to December. M a t e r i a l Examined: 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), V.26.59 (N.3. F i l m e r ) , 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), V.19.59, (N.3. F i l m e r ) , 1 Nymph: B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), VI.9.59 (N.3. F i l m e r ) , 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), VII.1.59 (N.3. F i l m e r ) . -144-SUPERFAIYIILY LEPTQPHLEBIOIDEA  Key To A d u l t s 1. H i n d wings a b s e n t . Outer f o r k o f Rs of f o r e w i n g v e r y deep. P o s t e r i o r branch o f IYI i n f o r e w i n g and i n t e r c a l a r y between branches o f t h i s v e i n much s h o r t e r than a n t e r i o r b r a n c h , not e x t e n d i n g t o base of wing. F o r c e p s 3 - j o i n t e d F a m i l y T r i c o r y t h i d a e , S u b f a m i l y L e p t o h y p h i n a e Hind wing p r e s e n t . Outer f o r k of Rs of f o r e w i n g n o r m a l . P o s t e r i o r b ranch o f IYI o f f o r e w i n g normal. F o r c e p s 1, 2, or 3 j o i n t e d . . .. 2. 2. No t r u e i n t e r c a l a r i e s i n f o r e w i n g between median i n t e r c a l a r y and p o s t e r i o r branch of IYI, or between Pil and C u l . Male f o r c e p s w i t h 2 or 3 s h o r t t e r m i n a l j o i n t s . F a m i l y L e p t o p h l e b i i d a e , S u b f a m i l y L e p t o p h l e b i i n a e Two s h o r t i n t e r c a l a r i e s i n f o r e w i n g between median i n t e r c a l a r y and p o s t e r i o r branch o f IYI, a l s o between IYI and C u l . lYIale f o r c e p s w i t h a s i n g l e s h o r t t e r m i n a l j o i n t . . . . . . . . . F a m i l y E p h e m e r e l l i d a e , S u b f a m i l y E p h e m e r e l l i n a e Key To Nymphs 1. G i l l s p r e s e n t on segments 1 to 7. No e l y t r o i d g i l l s . G i l l s t u n i n g - f o r k shaped, w i t h o u t f r i n g e d m a r g i n s . Depressed m a n d i b u l a r t u s k s v i s i b l e from above F a m i l y • L e p t o p h l e b i i d a e , S u b f a m i l y L e p t o p h l e b i i n a e G i l l s not on segments 1 to 7. lYlay o r may not be e l y t r o i d o r semi e l y t r o i d g i l l s . No m a n d i b u l a r t u s k s . 2. -145-2. ' G i l l s p r e s e n t on segment.3 or 4 to 7. G i l l s on segments 3 or 4 may be e l y t r o i d , semi e l y t r o i d , or s i m i l a r to t h o s e on segments 4 or 5 t o 7. A r u d i m e n t a r y g i l l i s o f t e n p r e s e n t on Segment 1 F a m i l y E p h e m e r e l l i d a e , S u b f a m i l y E p h e m e r e l l i n a e G i l l s p r e s e n t on segments 1 to 6 o n l y , r u d i m e n t a r y on segment 1. . G i l l s on Segment 2 e l y t r o i d ; t r i a n g u l a r o r o v a l , c o v e r i n g a l l o t h e r s F a m i l y T r i c o r y t h i d a e , S u b f a m i l y L e p t o h y p h i n a e SUBFAMILY LEPTOPHLEBIINAE A d u l t ; E y e s ' o f male not t u r b i n a t e j b u t -grooved;- h i n d femur u s u a l l y s h o r t e r than t i b i a , which .is l o n g e r than the t a r s u s ; t a r s i 4 - j o i n t e d y e x c e p t f o r a v e r y s h o r t e x t r a b a s a l j o i n t i n the male f o r e t a r s u s ; a l l c l a w s d i s s i m i l a r ; no t r u e i n t e r c a l a r i e s between t h e median i n t e r c a l a r y and•the p o s t e r i o r branch of the media i n the f o r e w i n g , or between t h e p o s t e r i o r b r a n c h o f the media and the a n t e r i o r b ranch of the c u b i t u s ; the two branches of the c u b i t u s u s u a l l y s e p a r a t e d at base; between t h e s e two branches are 2 to 4 l o n g i n t e r c a l a r i e s ; Of of f o r e w i n g and p o s t e r i o r b r a n c h of the media n o r m a l , a t t a c h e d b a s a i l y ; f i r s t a n a l v e i n ends i n the h i n d m a r g i n , but not by a s e r i e s o f v e i n l e t s ; Of of h i n d wing a b s e n t ; c o s t a l p r o j e c t i o n p r e s e n t or a b s e n t ; f o r c e p s 3 - j o i n t e d , a l t h o u g h t h e r e i s o c c a s i o n a l l y a s m a l l f o u r t h a p i c a l j o i n t ; b a s a l j o i n t l o n g e r than 'any o t h e r ; s u b a n a l p l a t e of female w i t h a d e e p l y e x c a v a t e d median c l e f t ; t a i l s t h r e e . Nymph; May be d e p r e s s e d i n head and t h o r a x w i t h head p r o g n a t h o u s , or compressed, w i t h head, hypognathous; m a n d i b l e s o f t e n v i s i b l e d o r s a l l y ; may be d e p r e s s e d m a n d i b u l a r t u s k s , v i s i b l e d o r s a l l y ; l a b i a l p a l p i 3 - j o i n t e d ; a l l c l a w s s i m i l a r , d e n t i c u l a t e ; g i l l s p r e s e n t on segments -146-1-7; g i l l s f o r k e d , w i t h o u t f r i n g e d m a r g i n s , or w i t h o u t e r margins b e a r i n g l o n g f r i n g e s which are u n i t e d a t the base, o r t e r m i n a t i n g i n a f i l a m e n t or p o i n t ; p o s t e r o - l a t e r a l s p i n e s p r e s e n t on segments 8 and 9, or 9 o n l y ; t a i l s 3, the o u t e r t a i l s f r i n g e d on both s i d e s . SUBFAMILY LEPTOPHLEBIINAE  Key To A d u l t s 1. M i d d l e t a i l s h o r t e r and weaker than l a t e r a l s B l a s t u r u s Eaton M i d d l e t a i l a p p r o x i m a t e l y e q u a l t o l a t e r a l s i n l e n g t h and t h i c k n e s s . ..2. 2. Penes s e p a r a t e d a l m o s t t o base. A l o n g f l a p - l i k e appendage, narrowed d i s t a l l y , i s a t t a c h e d near apex of each p e n i s and e x t e n d s i n w a r d and downward between l o b e s of penes..... L e p t o p h l e b i a iUestwood Penes not s e p a r a t e d a l m o s t t o base. U s u a l l y two s e t s o f appendages, an upper and s h o r t e r p a i r e x t e n d i n g l a t e r a l l y , and a l o n g e r p a i r ( t h e r e f l e x e d s p u r ) e x t e n d i n g backward, o f t e n o b l i q u e l y P a r a l e p t o p h l e b i a L e s t a g e Key To Nymphs 1. G i l l s b r o a d , not l o b e d , l a m e l l i f o r m . G i l l on segment 1 d i f f e r e n t from r e s t , b i f i d e x c e p t a t b ase...... B l a s t u r u s Eaton G i l l s l a n c e o l a t e , and t u n i n g - f o r k shaped. G i l l on segment 1 l i k e a l l the r e s t P a r a l e p t o p h l e b i a L e s t a g e GENUS LEPTOPHLEBIA UIESTUJOOD L e p t o p h l e b i a , Needham, 1935, The B i o l o g y of M a y f l i e s , 507 ( B i b l i o g r a p h y ) A d u l t : Male f o r e t a r s u s l o n g e r than t i b i a ; p o s t e r i o r branch o f Of o f Rs of f o r e w i n g sagged to r e a r w a r d ; h i n d wing w i t h no c o s t a l p r o j e c t i o n -147-but a s l i g h t c o n c a v i t y near the m i d d l e of the a n t e r i o r m a r g i n ; media of h i n d wing f o r k e d ; penes s e p a r a t e d a l m o s t to base; a l o n g , d i s t a l l y narrowed, f l a p - l i k e appendage ex t e n d s i n w a r d and downward from the apex of each p e n i s , r e a c h i n g between the l o b e s o f the penes; c l e f t i n the base of each f o r c e p s ; c l e f t i n a p i c a l margin of s u b a n a l p l a t e o f female deep; l o n g , a p p r o x i m a t e l y e q u a l i n l e n g t h and t h i c k n e s s . Nymph: Labrum much narrower than the head; 5-6 m a x i l l a r y s p i n e s ; 1 row o f t e e t h on c l a w s ; g i l l s b r o a d , l a n c e o l a t e , not f r i n g e d ; g i l l s on segment 1 b i f i d , e x c e p t at base, d i f f e r i n g i n form from f o l l o w i n g p a i r s ; no l a t e r a l l o b e s on bases of g i l l s ; t e r m i n a l e x t e n s i o n o f each g i l l . l o n g and s l e n d e r ; w e l l - d e v e l o p e d p o s t e r o - l a t e r a l ' s p i n e s on segments 8 and 9; p o s t e r i o r margins o f a l l a bdominal t e r g i t e s w i t h a dense row of minute s p i n u l e s . Genotype: L e p t o p h l e b i a v e s p e r t i n a ( i n Ephemera) L i n n a e u s LEPTOPHLEBIA ' Key To A d u l t s 1. S h i n y dark brown. C, Sc and R, brown, heavy, o t h e r v e i n s p a l e brown. S h o r t , s t o u t abdomen. D i s t i n c t c r o s s v e i n s between IY12 and Cu , s p . l S h i n y dark brown, but a n t e r i o r 1/4 of t e r g i t e s 2-7 p a l e h y a l i n e . Long, s l e n d e r abdomen. F a i n t c r o s s v e i n s between IYI2 and Cu. C, Sc and R, y e l l o w , heavy, o t h e r v e i n s p a l e sp. 2 L e p t o p h l e b i a s p . 1  A d u l t : A s h i n y dark brown s p e c i e s ; l e g s r e d d i s h y e l l o w , f o r e l e g s d a r k e r ; -148-C, Sc and R l heavy, dark brown, o t h e r v e i n s l i g h t brown. Nymph; Unknown D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: 2 Female, B r i t i s h C o l u m b i a : G h i l c o t i n , VI.16.29, ( G . J . S p e n c e r ) , 2 subimagos, B r i t i s h C o l u m b i a : C h i l c o t i n , VI.15.29 ( G . J . S p e n c e r ) l . s u b i m a g o , B r i t i s h C o l u m b i a : Q u e s n e l , VII.16.49 ( G . J . S p e n c e r ) 1 subimago, B r i t i s h C o l u mbia: Q u e s n e l , VI.25.49 ( G . J . S p e n c e r ) 1 Female, B r i t i s h C o l u m b i a : P h i l i l l o a Lake, VI.6.60, (E.Adams). L e p t o p h l e b i a sp. 2  A d u l t : ( M a l e ) A s h i n y dark b r o w n ' s p e c i e s ; l e g s brown, t a r s i p a l e ; C, SC, R l of f o r e w i n g y e l l o w , heavy, o t h e r v e i n s p a l e ; f a i n t c r o s s v e i n s between M2 and Cu; a n t e r i o r l / 4 of abdominal t e r g i t e s 2-7 p a l e h y a l i n e ; t a i l s and f o r c e p s p a l e . . Nymph: Unknown D i s t r i b u t i o n ; B r i t i s h C olumbia M a t e r i a l Examined: 1 fflale, B r i t i s h C o l u m b i a : Haney, V I I . 7 . 4 8 , 1 Male, B r i t i s h C o l u m b i a : Haney, VII.5.48 1 fflale, B r i t i s h C o l u mbia: C h i l c o t i n , VI.16.29 ( G . J . S p e n c e r ) 1 male, B r i t i s h C o l u m b i a : C h i l c o t i n , VI.12.31 ( G . J . S p e n c e r ) 1 fflale, B r i t i s h Columbia;: D e p a r t u r e Bay, VI.10.25 ( G . J . Spencer) : 1 ?, B r i t i s h C o l u m b i a : Vancouver, VI.3.34 ( J . K . J a c o b ) , 1 subimago B r i t i s h C olumbia: Q u e s n e l , VI.25.49 .('G.J. S p e n c e r ) , 1 subimago . B r i t i s h C o l u mbia: Q u e s n e l , V I I I . 7 . 4 8 ( G . J . S p e n c e r ) . 1 ? K e t t l e V a l l e y , V I . - V I I I . 3 5 . -149-• GENUS BLASTURUS EATON B l a s t u r u s , Needham, 1935, The B i o l o g y of M a y f l i e s , 531 ( B i b l i o g r a p h y ) A d u l t ; L a r g e , brown, r e d d i s h - b r o w n , or b l a c k i s h m a y f l i e s ; f o r e l e g s d a r k , o t h e r s ; p a l e ; no bands on femora; knee caps n a r r o w l y c r o s s - l i n e d w i t h b l a c k ; wings s u b h y a l i n e ; may be c l o u d e d w i t h brown; u s u a l l y a l i t t l e d a r k e r toward the c o s t a ; numerous i r r e g u l a r and anastomosing s t i g m a t i c c r o s s v e i n s ; p o s t e r i o r branch of Of of Rs of f o r e w i n g sags t o r e a r w a r d ; h i n d wing w i t h no c o s t a l p r o j e c t i o n ; c o s t a l margin s l i g h t l y concave a t m i d d l e ; abdomen l i g h t e r i n c o l o u r than t h o r a x , e s p e c i a l l y i n m i d d l e segments, and p a l e r j o i n i n g s of segments g i v e abdomen an a n n u l a t e appearance; t e r g i t e s w i t h a p a l e narrow median l i n e , on each s i d e of which i s a p a i r of o b l i q u e p a l e marks i n a n t e r i o r p o r t i o n o f each t e r g i t e ; f o r c e p s 4 - j o i n t e d o c c a s i o n a l l y , o t h e r w i s e 3 - j o i n t e d ; penes l o n g , s e p a r a t e d by a U-shaped n o t c h ; a s m a l l a c u r v i n a t e s p i n e a t t i p of each p e n i s ; each p e n i s w i t h a l a r g e , f l a t t e n e d , c u r v e d r e f l e x e d s p u r which r e a c h e s t o the base o f the n o t c h ; s u b a n a l p l a t e o f female p r o l o n g e d and d e e p l y e m a r g i n a t e ; t a i l s t h r e e , m i d d l e one weaker and s h o r t e r than the l a t e r a l s , u s u a l l y d a r k e r a t j o i n i n g s . Nymph; Claws w i t h a double row of d e n t i c l e s ; g i l l s on segments 1-7, l a m e l l i f o r m , t h o s e of t h e m i d d l e segments w i t h one or two b l u n t l o b e s a t the bases of the t e r m i n a l e x t e n s i o n s ; t e r m i n a l e x t e n s i o n s v e r y l o n g and s l e n d e r ; g i l l on segment 1 not l i k e the r e s t , narrow, b i f i d e x c e p t a t base; g i l l l a m e l l a e wide, margins e n t i r e i n segments 1 and 7; i n r e s t t e r m i n a l f i l a m e n t d e e p l y notched on one or both s i d e s ; -150-p o s t e r o - l a t e r a l s p i n e s on t e r g i t e s 8 and 9; t a i l s 3, a l l much t h e same i n . l e n g t h and t h i c k n e s s . Genotype: B l a s t u r u s c u p i d u s ( i n Ephemera) Say BLASTURUS  Key To A d u l t s 1. B r o w n i s h c l o u d e x t e n d i n g a c r o s s o u t e r t h i r d o f wing t i p . T a i l j o i n i n g s dark brown. M i d d l e t a i l l / 4 l e n g t h o f l a t e r a l t a i l s ..... n e b u l o s u s (UJalker) No c l o u d o r band on o u t e r p o r t i o n o f f o r e w i n g . T a i l j o i n i n g s dark brown or o b s c u r e . M i d d l e t a i l not l e s s t h a n l / 3 l e n g t h of the l a t e r a l t a i l s 2. 2. T a i l j o i n i n g s w h i t i s h , w i t h dark brown j o i n i n g s s p . 1 T a i l j o i n i n g s l i g h t or da r k , j o i n i n g s o b s c u r e 3. 3. T a i l s w h i t i s h to l i g h t t a n . Fore femur red-brown...cupidus (Say) T a i l s brown. Fore femur brown q r a u a s t e l l a (^-aton) Key To Nymphs 1. Upper p o r t i o n o f 3 r d p a i r of g i l l s w i t h a median e x t e n s i o n o f main t r a c h e a s h o r t e r than g i l l p l a t e p r o p e r . L a t e r a l l o b e s a t t i p of lower g i l l o f 3 r d p a i r a p p r o x i m a t e l y e q u a l i n l e n g t h . . . c u p i d u s (Say) Upper p o r t i o n of 3 r d p a i r of g i l l s w i t h a median e x t e n s i o n o f main t r a c h e a as l o n g as or l o n g e r t h a n g i l l p l a t e p r o p e r . L a t e r a l l o b e s on lo w e r p o r t i o n o f 3 r d p a i r unequal i n l e n g t h . . n e b u l o s u s (UJalker) Unknown: B l a s t u r u s q r a u a s t e l l a ( E a t o n ) -151-BLASTURU5 CUPIDU5 (SAY) B l a s t u r u s c u p i d u s ( S a y ) , Needham, 1935, The B i o l o g y of M a y f l i e s , 535 ( B i b l i o g r a p h y ) A d u l t : A b l a c k i s h s p e c i e s ; l e g s brown, f o r e femora d a r k e r red-brown w i t h n a r r o w l y b l a c k l i n e d knee c a p s ; wings s u b h y a l i n e , opaque; s t i g m a t i c a r e a s s t a i n e d brown; v e n a t i o n brown, d a r k e r i n s t i g m a t i c a r e a ; c r o s s v e i n s i n s t i g m a t i c a r e a i r r e g u l a r and a n a s t o m o s i n g ; abdominal t e r g i t e s dark brown becoming b l a c k i s h towards the ends; apex of 10th t e r g i t e y e l l o w i s h ; p a l e m i d - d o r s a l l i n e o b s c u r e or a b s e n t ; o b l i q u e p a i r e d s p o t s c r e s c e n t i c and may be s u f f u s e d w i t h b l a c k i s h , s p i r a c l e s marked by minute b l a c k e l o n g a t e dashes; s t e r n i t e s fawn c o l o u r ; s t e r n i t e 9 dark brown; t a i l s 3, m i d d l e t a i l l / 3 the l e n g t h o f the l a t e r a l s ; t a i l j o i n i n g s o b s c u r e l y brown, bands b e i n g a l t e r n a t e l y wide and narrow; penes as i n f i g . 3. Nymph: 6-7 l a r g e p e c t i n a t e s p i n e s below the crown of the m a x i l l a ; l e g s not banded, or w i t h i n d i s t i n c t bands; upper p o r t i o n o f the t h i r d p a i r o f g i l l s w i t h the median e x t e n s i o n o f the main t r a c h e a s h o r t e r than the g i l l p l a t e p r o p e r ; l a t e r a l l o b e s a t the t i p o f the lo w e r p o r t i o n s o f the 3 r d p a i r of g i l l s a p p r o x i m a t e l y e q u a l i n l e n g t h ; p o s t e r o - l a t e r a l s p i n e s on t e r g i t e B s h o r t e r t h a n t h o s e on t e r g i t e 9, which a re b l u n t , not e x t e n d i n g to the c e n t e r o f t e r g i t e 10. D i s t r i b u t i o n : New York, Ohio, M a s s a c h u s e t t s , B r i t i s h C o l u m b i a . No specimens of t h i s s p e c i e s were examined. -152-BLASTURU5 GRAUASTELLA (EATOIM) B l a s t u r u s q r a v a s t e l l a ( E a t o n ) , Needham, 1935, The B i o l o g y o f May-f l i e s , 537 ( B i b l i o g r a p h y ) • A d u l t : ffl dark s p e c i e s , l e g s brown; wings h y a l i n e , a brown s t a i n i n the s t i g m a t i c a r e a o f the f o r e w i n g ; v e n a t i o n y e l l o w i s h - b r o w n e x c e p t i n b a s a l p o r t i o n ; s t i g m a t i c c r o s s v e i n s r e g u l a r and opaque; abdominal t e r g i t e s brown, m i d d l e segments l i g h t e r w i t h p a l e r j o i n i n g s ; m i d - d o r s a l p a l e l i n e v e r y f a i n t , b r o a d l y d i l a t e d a t p o s t e r i o r margins o f m i d d l e segments; p a i r e d o b l i q u e s p o t s c b s c u r , l i n e a r , c o n f l u e n t a n t e r i o r l y w i t h p a l e j o i n i n g s ; s t e r n i t e s p a l e r , u n i c o l o u r e d ; . t a i l s 3, m i d d l e t a i l , l / 3 t o l / 2 the l e n g t h o f the l a t e r a l s ; t a i l s brown, o b s c u r e l y and u n i f o r m l y t i n g e d w i t h d a r k e r brown. Nymph: Unknown D i s t r i b u t i o n : C o l o r a d o , B r i t i s h Columbia No specimens of t h i s s p e c i e s were examined. BLASTURUS NEBULOSUS (UJALKER) B l a s t u r u s n e b u l o s u s ( U J a l k e r ) , Needham, 1935, The B i o l o g y o f M a y f l i e s , 538 ( B i b l i o g r a p h y ) A d u l t : A b r o w n i s h b l a c k s p e c i e s ; f o r e l e g s r e d d i s h brown, femora p a l e r ; m i d d l e and h i n d l e g s y e l l o w i s h ; wings h y a l i n e ; f o r e w i n g s w i t h a b r o w n i s h c l o u d e x t e n d i n g a c r o s s a p i c a l 1/3 of the wing; v e n a t i o n brown; c o s t a l c r o s s v e i n s f a i n t e x c e p t i n s t i g m a t i c a r e a where they are i r r e g u l a r , crowded, and s l i g h t l y a n a s t o m o s i n g ; abdominal t e r g i t e s brown, d a r k e r on segments 1, 2, 8 and 9; p a l e m i d - d o r s a l l i n e v e r y f i n e and p a r t l y i n t e r r u p t e d ; o b l i q u e mark c r e s c e n t i c , i s o l a t e d ; -153-j o i n i n g s of m i d d l e segments w h i t i s h ; s t e r n i t e s p a l e r ; t a i l s p a l e brown o r g r e y i s h , r i n g e d a t j o i n i n g s w i t h dark brown; t a i l s 3, m i d d l e on l / 4 the l e n g t h of the i a t e r a l s ; l o b e s of f o r c e p s base s e p a r a t e d by a s h a r p l y U-shaped c l e f t and w i t h s u b - t r u n c a t e a p i c e s ; penes s e p a r a t e d by a g o b l e t - s h a p e d c l e f t ; r e f l e x e d spur s t r o n g l y b e n t , d i l a t e d a t t i p , and e x t e n d i n g below the l e v e l of the c l e f t . Nymph: 6-7 p e c t i n a t e s p i n e s below the crown of the m a x i l l a ; l e g s not banded, or w i t h i n d i s t i n c t bands; upper p o r t i o n o f 3 r d p a i r of g i l l s w i t h the media e x t e n s i o n of the main t r a c h e a as l o n g as or l o n g e r than the g i l l p l a t e p r o p e r ; l a t e r a l l o b e s o f lower p o r t i o n o f 3 r d p a i r o f g i l l s u n e q u a l i n l e n g t h ; p o s t e r o - l a t e r a l s p i n e on t e r g i t e 8 s h o r t e r than t h a t on t e r g i t e 9. D i s t r i b u t i o n ; Maine, C o l o r a d o , Wyoming, New York, U i r g i n i a , B r i t i s h C o l u m b i a . M a t e r i a l Examined: The a u t h o r has examined 41 specimens, a l l m a l e s , from the f o l l o w i n g l o c a l i t i e s : B r i t i s h C o l u m b i a : N i c o l a Lk., U.21.44; N i c o l a , VI.21.44; N i c o l a , . VI.27.43; Lake La Hache, VI.8.47; N i c o l a , VI.19.46; N i c o l a , VI.27.46; N i c o l a , VI.21.46. A l l specimens were t a k e n by Mr. G.J. Spenc e r . B l a s t u r u s s p . 1  A d u l t : (Female) Very s i m i l a r to B. n e b u l o s u s ; no c l o u d on wing; f o r e femur r e d -brown; t a i l s w h i t i s h , t a i l j o i n i n g s d a r k . Nymph: . Unknown D i s t r i b u t i o n : B r i t i s h Columbia -154-f / i a t e r i a l Examined: 3 Female, B r i t i s h C o l u m b i a : Lac La Hache, VI.8.47 ( G . J . S p e n c e r ) '6 Female, B r i t i s h C o l u m b i a : N i c o l a , VI.27.43 ( G . J . S p e n c e r ) 5 Female, B r i t i s h C o l u m b i a : N i c o l a , VI.19.46 ( G . J . S p e n c e r ) 3 Female, B r i t i s h C o l u m b i a : N i c o l a , VI.21.44 ( G . J . Sp e n c e r ) T h i s i s p o s s i b l y the female of B l a s t u r u s n e b u l o s u s ( U J a l k e r ) . GENUS PARALEPTOPHLEBIA LESTAGE P a r a l e p t o p h l e b i a , Needham, 1935, The B i o l o g y o f M a y f l i e s , 510 ( B i b l i o g r a p h y ) A d u l t : A s m a l l t o medium-sized s p e c i e s , sexes d i f f e r e n t i n c o l o u r ; males w i t h b l a c k i s h head, t h o r a x , and t i p of abdomen; female r e d d i s h o r r e d d i s h brown; l e g s y e l l o w i s h o r b r o w n i s h , w i t h o u t banded femora; p o s t e r i o r branch of Of of Rs of f o r e w i n g sagged t o r e a r w a r d ; no c o s t a l p r o j e c t i o n on h i n d wing, and c o s t a l margin s l i g h t l y concave i n c e n t e r ; median v e i n f o r k e d ; no i n t e r c a l a r i e s i n c u b i t a l f o r k , or between c u b i t u s and media; wings h y a l i n e , may be t i n t e d w i t h amber; m i d d l e abdominal segments i n mala dark brown, o r w h i t i s h , w i t h o r w i t h o u t o b s c u r e b r o w n i s h m a r k i n g s ; penes w i t h one, u s u a l l y 2 p a i r s o f appendages, the upper o f a p i c a l p a i r s h o r t e r and e x t e n d i n g l a t e r a l l y , the lower p a i r l o n g e r r e f l e x e d s p u r s e x t e n d i n g backwards, o f t e n o b l i q u e l y ; penes not s e p a r a t e d a l m o s t to base; f o r c e p s u s u a l l y 3 - j o i n t e d , a l t h o u g h t h e r e may be a 4 t h j o i n t by the a d d i t i o n of a s h o r t b a s a l r i n g - l i k e j o i n t o r a t e r m i n a l j o i n t ; c l e f t i n base of f o r c e p s ; a p i c a l margin of s u b a n a l p l a t e of femal e w i t h a deep median c l e f t ; t a i l s t h r e e , e q u a l i n l e n g t h and t h i c k n e s s , s l i g h t l y l o n g e r than the body. -155-Nymph: Nymphs s l e n d e r , compressed, head may be somewhat d e p r e s s e d ; m o uthparts as i n B l a s t u r u s and L e p t o p h l e b i a ; labrum much narrower than head, w i t h a s h a l l o w i n d e n t a t i o n on a n t e r i o r b o r d e r ; 4-6 l a r g e p e c t i n a t e s p i n e s below crown of the m a x i l l a ; c l a w s s l e n d e r and p e c t i n a t e , one row o n l y ; g i l l s n a r r o w l y l a n c e o l a t e , t u n i n g f o r k - s h a p e d or more d e e p l y d i v i d e d , not f r i n g e d on m a r g i n s ; g i l l s not d i m i n i s h e d i n s i z e t o r e a r w a r d , 1 s t p a i r s i m i l a r t o o t h e r s ; s p i n u l e s p r e s e n t . on p o s t e r i o r margins o f abdominal t e r g i t e s 1-10; p o s t e r o - l a t e r a l s p i n e s on t e r g i t e s 8 and 9, or 9 o n l y , those on 9 not more th a n 1/4 the l e n g t h o f the segment. Genotype; P a r a l e p t o p h l e b i a c i n c t a ( i n L e p t o p h l e b i a ) Eaton PARALEPTOPHLEBIA " Key To A d u l t s 1. Penes w i t h r e f l e x e d spur on p e n i s t i p 2. Penes w i t h no r e f l e x e d s p u r on p e n i s t i p . . . . . . .5. 2. Conspi c u o u s l o b e on b a s a l j o i n t of f o r c e p s 3. No c o n s p i c u o u s l o b e on b a s a l j o i n t o f f o r c e p s 4. 3. T i p s o f penes w i t h a p a i r o f c o n v e r g e n t wide l o b e s p r o j e c t i n g w i t h i n the a p i c a l n o t c h . Wing l e n g t h 10 mm. . b i c o r h u t a (McD) T i p s o f penes w i t h no l o b e s w i t h i n the a p i c a l n o t c h . Wing l e n g t h 8 mm .., d e b i l i s ( W a l k e r ) 4. M i d d l e abdominal t e r g i t e s p r e d o m i n a n t l y b r o w n . . . q r e g a l i s ( E a t o n ) M i d d l e abdominal t e r g i t e s w h o l l y w h i t e . . . . . v a c i v a ( E a t o n ) 5. M i d d l e abdominal t e r g i t e s c l o u d e d or b o r d e r e d w i t h b l a c k or brown, but p r e d o m i n a n t l y w h i t e . 6. M i d d l e abdominal t e r g i t e s p r e d o m i n a n t l y b r o w n . . r u f i v e n o s a ( E a t o n ) -156-'' 6. Penes w i t h a p i c a l t e e t h 7. Penes w i t h no a p i c a l t e e t h h e t e r o n e a (fflcD) 7. B l a c k t r a n s v e r s e dash . i n p o s t e r o - l a t e r a l c o r n e r s of t e r g i t e s 2-6, remainder of a p i c a l margin p a l e , p a l l i p e s (Hagen) E n t i r e a p i c a l m a r g i n of each m i d d l e abdominal t e r g i t e n a r r o w l y black' . t e m p o r a l i s (HflcD) Key To Nymphs 1. M a n d i b l e w i t h t u s k s , .2. M a n d i b l e w i t h no t u s k s 5. 2. M a n d i b l e w i t h t u s k l o n g e r than the head .3. fflandible w i t h t u s k not as l o n g as head 4. 3. M a n d i b u l a r tu s k more than t w i c e the l e n g t h of the body of the m a n d ible • • *sp. 3 M a n d i b u l a r t u s k o n l y s l i g h t l y l o n g e r than the body of the mandible...' .. . b i c o r n u t a (McD) 4. Antennae w i t h no dark m e d i a l band. Legs p a l e , b a r r e d w i t h d a r k e r brown d e b i l i s (UJalker) Antennae w i t h a dark m e d i a l band. Legs d a r k , w i t h p a l e a p i c a l t r a n s v e r s e bands on femora »sp. 4 5. L a t e r a l branches on g i l l t r a c h e a e .6. No l a t e r a l branches on g i l l t r a c h e a e 8 6. Fore t i b i a e not marked w i t h dark margins 7 Fore t i b i a e marked w i t h a dark margin • sp. 2 7. O c c i p u t dark p a l l i p e s (Hagen) O c c i p u t p a l e .. .sp. 5 8.. A few m i d d l e a b d o m i n a l segments p a l e s p o t t e d . . . . q r e q a l i s ( E a t o n ) A l l a b dominal segments p a l e s p o t t e d . . . sp. 1 -157-Unknown: P a r a l e p t o p h l e b i a h e t e r o n e a (IYlcD) P a r a l e p t o p h l e b i a r u f i v e n o s a ( E a t o n ) P a r a l e p t o p h l e b i a t e m p o r a l i s (IYlcD) P a r a l e p t o p h l e b i a v a c i v a ( E a t o n ) PARALEPTOPHLEBIA BICORIMUTA (lYlcDUNNOUGH) P a r a l e p t o p h l e b i a b i c o r n u t a (McDunnough), Needham, 1935, The B i o l o g y of M a y f l i e s , 517 ( B i b l i o g r a p h y ) A d u l t : . Head and t h o r a x b l a c k i s h broiun, above, p a l e r b e n e a t h ; wings h y a l i n e , v e n a t i o n brown; c o s t a l c r o s s v e i n s o b s o l e t e e x c e p t i n s t i g m a t i c a r e a where they a r e numerous, l o n g , a s l a n t ; and may be f o r k e d ; abdominal t e r g i t e 1 dark brown, 2 l i g h t e r , 8 t o 10 red-brown, 3-7 w h i t e w i t h p o s t e r i o r h a l f c l o u d e d o r b o r d e r e d w i t h brown o r b l a c k ; s t e r n i t e 1 brown, 8 and p o s t e r i o r h a l f of 9 b r i g h t r e d d i s h brown, r e s t f a i n t l y t i n g e d w i t h brown; b a s a l j o i n t of f o r c e p s brown, r e s t w h i t e ; a c o n s p -i c u o u s d o r s a l l o b e on the b a s a l j o i n t of the f o r c e p s ; penes b r o a d l y s e p a r a t e d by a very wide U-shaped n o t c h ; penes d i l a t e d and t r u n c a t e d a t t i p ; a p a i r of l o n g f l a t l o b e s c o n v e r g i n g by t h e i r rounded ends w i t h the n o t c h a re a t t a c h e d t o the d o r s a l s i d e o f the penes j u s t b e f o r e t h e i r t i p s ; r e f l e x e d s p u r b i f i d , a l m o s t c r e s c e n t i c , a t t a c h e d by back of c r e s c e n t , o u t e r horn l o n g e r ; t a i l p a l e brown. Nymph: m a n d i b l e ' w i t h a f o r w a r d p r o j e c t i n g tusk t h a t i s l o n g e r than the head, and o n l y s l i g h t l y l o n g e r than the body o f the m a n d i b l e ; g i l l t r a c h e a e w i t h no or a few l a t e r a l b r a n c h e s . E c o l o g y : T h i s s p e c i e s was t a k e n from the m i d d l e and edges of v a r i o u s -158-l o c a t i o n s on the A l o u e t t e R i v e r , u s u a l l y a t a depth o f 1 to 2 f e e t a l t h o u g h they have a l s o been t a k e n a t a depth o f 5 f e e t . The stream bed v a r i e d from mud, th r o u g h sand, g r a v e l , r o c k s , b o u l d e r s , to bedr o c k . The c u r r e n t v a r i e d from slow and q u i e t to r i p p l e s . A l l . specimens were c o l l e c t e d d u r i n g the months of Dul y , August, and September. D i s t r i b u t i o n ; A l b e r t a , Montana, B r i t i s h C olumbia M a t e r i a l Examined; 3 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), V I I I . 1 1 . 5 9 (N.D. F i l m e r ) . i PARALEPTOPHLEBIA DEB I LIS. (UJALKER ) P a r a l e p t o p h l e b i a d e b i l i s ( U J a l k e r ) , Needham, 1935, The B i o l o g y o f M a y f l i e s , 519 ( B i b l i o g r a p h y ) A d u l t ; Head and t h o r a x a deep r i c h brown; wings h y a l i n e ; v e n a t i o n p a l e ; c o s t a l c r o s s v e i n s o b s o l e t e e x c e p t i n s t i g m a t i c a r e a where they a r e numerous, s i m p l e , c u r v e d , a s l a n t , and o b s o l e s c e n t a t s u b c o s t a l ends; abdominal t e r g i t e s 1 and 8-10 deep r i c h brown; t e r g i t e s 3-7 w h i t e , w i t h p o s t e r i o r margins b r o a d l y b o r d e r e d w i t h b r o w n i s h p u r p l e ; s p i r a c l e s marked w i t h a brown p o i n t and a round brown spot a n t e r i o r to each above t h e l a t e r a l margin of the t e r g i t e s ; g a n g l i a marked w i t h y e l l o w ; b a s a l j o i n t of f o r c e p s w i t h a l a r g e , v e n t r a l , l o b e - l i k e d i l a t i o n ; penes s e p a r a t e d by a U-shaped n o t c h ; t i p s of penes w i t h no l o b e w i t h i n the a p i c a l n o t c h , but penes d i l a t e d a t t i p s , and on the o u t e r s i d e o f each t i p t h e r e i s a r e c u r v e d l a t e r a l t o o t h ; r e f l e x e d spur t w i c e as l o n g as the depth o f the n o t c h , a r c u a t e , o u t c u r v i n g and a c u t e a t t i p ; t a i l s w h i t e . -159-Nymph: Head brown d o r s a l l y w i t h a dark v e r t e x ; antennae w i t h no dark m e d i a l band; m a n d i b l e s s m a l l , o n l y a s m a l l p o r t i o n v i s i b l e d o r s a l l y , t i p s not e x t e n d i n g beyond head; no m a n d i b u l a r t u s k ; m a x i l l a r y p a l p 3 - j o i n t e d , the 1 s t j o i n t e q u a l i n l e n g t h t o the o t h e r two t o g e t h e r ; l e g s p a l e , banded w i t h d a r k e r brown; m i d d l e abdominal t e r g i t e s p a l e s p o t t e d ; g i l l t r a c h e a e w i t h o u t c o n s p i c u o u s l a t e r a l b r a n c h e s ; p o s t e r o -l a t e r a l s p i n e s on t e r g i t e s 8 and 9. D i s t r i b u t i o n ; New York, P e n n s y l v a n i a , Ohio, A l b e r t a , Washington, B r i t i s h C o l u m b i a . M a t e r i a l Examined; 2 Nymphs, B r i t i s h C o l u m b i a : N i c o l a Creek (G.G.E. S c u d d e r ) . PARALEPTOPHLEBIA GREGALIS (EATON) P a r a l e p t o p h l e b i a g r e g a l i s ( E a t o n ) , S p i e t h , 1941, Ann. E n t . Soc. Amer. 34:94 ( B i b l i o g r a p h y ) A d u l t : . A r e d d i s h brown m a y f l y ; t h o r a x b l a c k i s h d o r s a l l y ; wings h y a l i n e ; v e n a t i o n p a l e , w i t h l o n g i t u d i n a l v e i n s and s t i g m a t i c c r o s s v e i n s t i n g e d w i t h brown; s t i g m a t i c c r o s s v e i n s 12 to 16 i n number, somewhat b r a n c h i n g , i r r e g u l a r ; a l l abdominal t e r g i t e s brown, d a r k e r a t j o i n i n g s o f m i d d l e segments; b a s a l j o i n t of f o r c e p s w i t h no b a s a l d i l a t i o n o r l o b e or s h o r t b a s a l s u b j o i n t , but i s c o n i c a l b a s a l l y , t h e n p a r a l l e l s i d e d f o r h a l f i t s l e n g t h , t h e n s l o w l y t a p e r i n g t o apex; 2nd j o i n t t w i c e as l o n g as the 3 r d j o i n t ; penes s e p a r a t e d by a broad U-shaped no t c h which i s a l m o s t c l o s e d by a p a i r of h y a l i n e , o b l o n g , b r o a d , f l a t , o b l i q u e l y c o n v e r g i n g l o b e s e x t e n d i n g f o r most of t h e i r l e n g t h -160-beyond the c h i t i n i z e d t i p , g i v i n g the n o t c h a f l a s k shape; apex of each p e n i s i s o b l i q u e l y t r u n c a t e , the s h o r t e x t e r n a l a n g l e e n d i n g i n a s h a r p backward t o o t h ; r e f l e x e d spur i s h y a l i n e , s e m i - e l l i p t i c a l w i t h a s t r a i g h t i s h e x t e r n a l margin and a convex i n t e r n a l m a r g i n , w i d e s t near base and g r a d u a l l y t a p e r i n g towards the a c u t e apex, i t s g r e a t e s t w i d t h not more than 1/3 i t s l e n g t h , a l i t t l e l o n g e r than the depth of the n o t c h ; l o b e s o f the d i v i d e d 10th s t e r n i t e b r o a d l y t r i a n g u l a r w i t h rounded ends; t a i l s d i n g y w h i t i s h , f e r r u g i n o u s b a s a i l y . Nymph: Head marked w i t h a w h i t e s p o t ; no m a n d i b u l a r t u s k s ; f o r e t i b i a e marked w i t h dark m a r g i n s ; a few m i d d l e abdominal t e r g i t e s p a l e s p o t t e d ; g i l l t r a c h e a e w i t h no l a t e r a l b r a n c h e s ; p o s t e r o - l a t e r a l s p i n e s on t e r g i t e s 8 and. 9. D i s t r i b u t i o n ; C a l i f o r n i a , B r i t i s h C olumbia No specimens of t h i s s p e c i e s were examined. PARALEPTOPHLEBIA HETERONEA (lYlcDUNNOUGH) P a r a l e p t o p h l e b i a h e t e r o n e a (lYlcDunnough), Needham, 1935, ^he B i o l o g y m a y f l i e s , 523 ( B i b l i o g r a p h y ) A d u l t : Head and t h o r a x r i c k r e d d i s h brown d o r s a l l y ; wings w h i t i s h ; no c o s t a l c r o s s v e i n s , e x c e p t f o r a few i r r e g u l a r ones i n the s t i g m a t i c a r e a ; b a s a l abdominal t e r g i t e s and t e r g i t e s 8-10 brown, r e s t w h i t i s h i n a n t e r i o r p o r t i o n s and brown or b l a c k i s h p o s t e r i o r l y , p o s t e r i o r band b e i n g w i d e s t on segments 4 and 5 and d i s a p p e a r i n g on 7; s p i r a c l e s b l a c k and c o n n e c t e d by a b l a c k broken l i n e ; b a s a l j o i n t of f o r c e p s w i t h no l o b e , but broad b a s a i l y , p a r a l l e l s i d e d to m i d d l e , t h e n -161-t a p e r i n g s t r o n g l y ; 3 r d j o i n t n e a r l y as .long as the 2nd, but much more s l e n d e r ; penes s e p a r a t e d by a U-shaped n o t c h ; penes notched on i n n e r and o u t e r margins near apex; no a p i c a l t e e t h o r r e f l e x e d s p u r s . Nymph: Unknown. D i s t r i b u t i o n : C o l o r a d o , A l b e r t a , B r i t i s h C o l u mbia. No specimens of t h i s s p e c i e s were examined. PARALEPTOPHLEBIA PALLIPES (HAGEN) P a r a l e p t o p h l e b i a p a l l i p e s (Hagen), Needham,1935, The B i o l o g y of May-f l i e s , 527 ( B i b l i o g r a p h y ) A d u l t : Head and t h o r a x b l a c k d o r s a l l y ; wings w h i t i s h , m i l k y a l o n g c o s t a l a r e a ; e s p e c i a l l y i n s t i g m a t i c a r e a ; s t i g m a t i c c r o s s v e i n s few i n number, o b s c u r e , s t r a i g h t , unbranched; extreme wing base t i n g e d w i t h brown; abdominal t e r g i t e 2 p a l e brown, 3-6 w h i t e w i t h t o u c h e s o f brown on p o s t e r i o r b o r d e r s , l a b i a l s p i r a c l e s , and a l s o on s p i r a c l e s ; t e r g i t e s 2-6 w i t h b l a c k t r a n s v e r s e dashes i n p o s t e r o - l a t e r a l c o r n e r s ; t e r g i t e s 7-10 brown; g a n g l i a y e l l o w ; b a s a l f o r c e p s j o i n t w i t h no l o b e , but i s i r r e g u l a r l y t a p e r e d t o i t s a p i c a l 4 t h and then s l i g h t l y widened; 3 r d j o i n t a l m o s t as l o n g as the 2nd but much more s l e n d e r ; penes s e p a r a t e d by a g o b l e t - s h a p e d n o t c h ; penes c o n s i s t o f l o n g s l e n d e r t u b e s b e h i n d each of which i s a l o n g , s harp p o s t e r i o r l y d i r e c t e d , c u r v i n g s p i n e on the o u t e r s i d e of e a c h , i t s l e n g t h more than h a l f the depth of the n o t c h ; penes w i t h a p i c a l t e e t h but no r e f l e x e d s p u r s . Nymph: Head marked w i t h a dark o c c i p u t ; no m a n d i b u l a r t u s k s ; f o r e t i b i a e not marked w i t h dark m a r g i n s ; g i l l t r a c h e a e w i t h l a t e r a l b r a n c h e s ; m i d d l e abdominal t e r g i t e s p a l e s p o t t e d . -162-D i s t r i b u t i o n : Oregon, C o l o r a d o , C a l i f o r n i a , B r i t i s h Columbia No specimens of t h i s s p e c i e s were examined. PARALEPTOPHLEBIA RUFIUENOSA (EATON) P a r a l e p t o p h l e b i a r u f i v e n o s a ( E a t o n ) , S p i e t h , 1941, Ann. E n t . 5oc. Amer., 34:96 ( B i b l i o g r a p h y ) A d u l t : Head and t h o r a x dark brown; wings s u b h y a l i n e ; v e n a t i o n r e d d i s h , c r o s s v e i n s p a l e r e x c e p t i n b a s a l l / 3 ; s t i g m a t i c c r o s s v e i n s s t r o n g l y t i n g e d , crowded, o b l i q u e , some f o r k e d ; m i d d l e abdominal segments p a l e brown, a p i c a l segments dark brown; no p a t t e r n on t e r g i t e s ; s t e r n i t e 9 n a r r o w l y d i v i d e d by a U-shaped n o t c h ; b a s a l f o r c e p s j o i n t w i t h no c o n s p i c u o u s l o b e , no b a s a l d i l a t i o n , and not marked o f f by a s h o r t b a s a l s u b j o i n t , but t a p e r s r e g u l a r l y t o apex, s l i g h t l y c o r r u g a t e d i n t e r n a l l y ; 3 r d segment as l a r g e as the 2nd; penes s e p a r a t e d i n t h e i r a p i c a l h a l v e s by a rounded U-shaped n o t c h ; margins o f penes p a r a l l e l a l m o s t to t i p where t h e r e i s a l a t e r a l l y p r o j e c t i n g t r i a n g u l a r t o o t h on each; no a p i c a l t e e t h or r e f l e x e d s p u r s on penes; t a i l s p a l e brown. Nymph: Unknown D i s t r i b u t i o n : Idaho, B r i t i s h Columbia No specimens of t h i s s p e c i e s were examined. PARALEPTOPHLEBIA TEMPORALIS (lYlcDUNNOUGH) P a r a l e p t o p h l e b i a t e m p o r a l i s (lYlcDunnough), Needham, 1935, The B i o l o g y of M a y f l i e s , 529 ( B i b l i o g r a p h y ) A d u l t : Head and t h o r a x brown d o r s a l l y ; wings s u b h y a l i n e ; v e n a t i o n p a l e brown; c o s t a l c r o s s v e i n s n e a r l y o b s o l e t e ; s t i g m a t i c c r o s s v e i n s s i n g l e , s t r a i g h t , w e l l spaced a p a r t ; abdominal t e r g i t e s 2—7 w h i t e w i t h -163-d i f f u s e and i l l - d e f i n e d narrow br o w n i s h or b l a c k i s h p o s t e r i o r m a r g i n s , d a r k e r on 2 and 7; s p i r a c l e s marked w i t h a b l a c k R-shaped mark e x t e n d -i n g back over the p o s t e r i o r - l a t e r a l c o r n e r ; b a s a l j o i n t o f f o r c e p s w i t h no c o n s p i c u o u s l o b e , but t a p e r e d t o 3/4 i t s l e n g t h ; penes d i v i d e d by a wide U-shaped n o t c h ; penes c o n s i s t o f l o n g , s t r a i g h t t u b e s on the o u t s i d e of which i s a l o n g s p i r a l l y t w i s t e d s p i n e , l y i n g i n the same p l a n e and as l o n g as the penes; penes w i t h a p i c a l t e e t h but no r e f l e x e d s p u r s . Nymph: Unknown D i s t r i b u t i o n : Oregon, B r i t i s h Columbia No specimens, of t h i s s p e c i e s were examined. PARALEPTOPHLEBIA UACIUA (EATON) P a r a l e p t o p h l e b i a v a c i v a ( E a t o n ) , S p i e t h , 1941, Ann. E n t . Soc. Amer. 34:96 A d u l t : Head and t h o r a x s h i n i n g b r o w n i s h b l a c k ; wings s u b h y a l i n e , f a i n t l y t i n g e d ; v e n a t i o n p a l e , but c o s t a l l o n g i t u d i n a l v e i n s and s t i g m a t i c c r o s s v e i n s p a l e ; s t i g m a t i c c r o s s v e i n s r e g u l a r and w i d e l y spaced; a b d o m i n a l segment 1 b l a c k , 2-7 t r a n s l u c e n t w h i t e w i t h f a i n t m i d - d o r s a l c l o u d s which a r e d a r k e r o n ' t e r g i t e 6 and s p r e a d d i f f u s e l y over more than h a l f o f t e r g i t e 7; t e r g i t e s 8-10 b l a c k i s h ; g a n g l i a marked w i t h brown, s t e r n i t e s 8-10 b r o w n i s h , no dark marks on s p i r a c l e s ; b a s a l f o r c e p s j o i n t w i t h no c o n s p i c u o u s l o b e ; penes l o n g , s e p a r a t e d by a narrow c l e f t ; penes t a p e r e d i n b a s a l h a l f , then i r r e g u l a r l y c y l i n d r i c a l ; on o u t e r margin of each p e n i s i s a v i s o r - l i k e b a c k w a r d - d i r e c t e d r e f l e x e d spur h a l f t h e i r own l e n g t h from the t i p ; t a i l s w h i t i s h . -164-Nymph: Unknown D i s t r i b u t i o n : Oregon, B r i t i s h C olumbia No specimens of t h i s s p e c i e s were examined. P a r a l e p t o p h l e b i a sp. 1  A d u l t : Unknown Nymph: A s h o r t , wide s p e c i e s ; no m a n d i b u l a r t u s k s ; each abdominal t e r g i t e w i t h a p a i r of s u b l a t e r a l dark d o t s ; g i l l s v e r y l o n g , t u n i n g - f o r k shaped; no l a t e r a l branches on g i l l t r a c h e a e ; p o s t e r o -l a t e r a l s p i n e s on t e r g i t e 9 l / 4 the l e n g t h o f the segment; a l l a b dominal t e r g i t e s p a l e s p o t t e d . E c o l o g y : T h i s s p e c i e s was c o l l e c t e d from many l o c a l i t i e s on the A l o u e t t e R i v e r , both from the m i d d l e and edges. . They have been found a t depths of 1 f o o t t o 5 f e e t , a l t h o u g h g e n e r a l l y a t 1 f o o t . The stream bed v a r i e d from mud, th r o u g h sand, g r a v e l , r o c k s and b o u l d e r s , t o b e d r o c k , .and the c u r r e n t from s l o w , q u i e t water to s w i f t r i p p l e s and r a p i d s . A l l specimens were t a k e n from dune to the f o l l o w i n g F e b r u a r y . D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: 3 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), V I I I . 5 . 5 9 ( N . J . F i l m e r ) P a r a l e p t o p h l e b i a sp. 2  A d u l t : Unknown • Nymph: Longer and narrower than P a r a l e p t o p h l e b i a sp. 1; no m a n d i b u l a r -165-t u s k s ; l o n g t u n i n g - f o r k shaped g i l l s ; l a t e r a l branches on g i l l t r a c h e a e ; no s p o t s on t e r g i t e s ; p o s t e r o - l a t e r a l s p i n e s on t e r g i t e 9 l / 4 the l e n g t h of the segment; f o r e t i b i a e marked w i t h a dark m a r g i n . E c o l o g y : These nymphs were found i n s i t u a t i o n s i d e n t i c a l to t h o s e i n which P a r a l e p t o p h l e b i a s p . 1 were found, and were j u s t as common. They were c o l l e c t e d , however, o n l y d u r i n g Way, Dune, D u l y , and October to F e b r u a r y . D i s t r i b u t i o n : B r i t i s h C olumbia M a t e r i a l Examined: 3 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), VI.16.59 (N.D. F i l m e r ) P a r a l e p t o p h l e b i a sp. 3  A d u l t T Unknown Nymph: M a n d i b u l a r t u s k l o n g e r than the head, and more tha n t w i c e the l e n g t h o f the body of the m a n d i b l e ; femora each w i t h a p a l e a p i c a l t r a n s v e r s e band; g i l l t r a c h e a e w i t h no l a t e r a l b r a n c h e s . D i s t r i b u t i o n : B r i t i s h C o l umbia M a t e r i a l Examined: 13 Nymphs, B r i t i s h C o l u m b i a : N i c o l a Creek (G.G.E. Scud d e r ) P a r a l e p t o p h l e b i a sp. 4  A d u l t : Unknown Nymph: M a n d i b u l a r , t u s k not as l o n g as the head, about as l o n g as the body of frie m a n d i b l e ; antennae w i t h a dark m e d i a l band; l e g s d a r k , -166-femora each w i t h a p a l e a p i c a l t r a n s v e r s e band; no v i s i b l e t r a c h e a e i n g i l l s . D i s t r i b u t i o n ; B r i t i s h Columbia M a t e r i a l Examined: 4 Nymphs, B r i t i s h C o l u m b i a : N i c o l a Creek (G.G.E. S c u d d e r ) P a r a l e p t o p h l e b i a sp. 5  A d u l t : Unknown Nymph: O c c i p u t p a l e ; p a l e s p o t between a n t e n n a l bases and one l a t e r a l to each o c e l l u s ; no m a n d i b u l a r t u s k s ; mandible not v i s i b l e d o r s a l l y ; f o r e t i b i a e not marked w i t h dark m a r g i n s ; g i l l t r a c h e a e w i t h l a t e r a l b r a n c h e s . D i s t r i b u t i o n : B r i t i s h C olumbia M a t e r i a l Examined: 12 Nymphs, B r i t i s h C o l u m b i a : Loon Creek ( C l i n t o n ) , V.19.59 (G.G.E. S c u d d e r ) ; 5 Nymphs, B r i t i s h C o l u m b i a : Loon Creek ( C l i n t o n ) VI.13.? (H. L o r z ) . SUBFAMILY EPHEMERELLINAE A d u l t ; Eyes o f male not t u r b i n a t e , but are grooved; t a r s i 4 - j o i n t e d , e x c e p t the f o r a t a r s u s o f male which has a s h o r t b a s a l j o i n t ; a l l c l a w s d i s s i m i l a r ; v e n a t i o n o f f o r e w i n g s i m i l a r t o t h a t i n B l a s t u r u s ; 2 or more s h o r t f r e e i n t e r c a l a r i e s between the median i n t e r c a l a r y and the p o s t e r i o r branch of the M, and a l s o between the l a t t e r and CU1; 2 c u b i t a l i n t e r c a l a r i e s ; Of and the p o s t e r i o r b ranch of the ffl normal and a t t a c h e d b a s a l l y ; p o s t e r i o r b ranch of the Of of the Rs -167-not sagged t o r e a r w a r d ; Cu2 s t r o n g l y a n g u l a t e b e f o r e t he m i d d l e ; 1 s t a n a l v e i n ends i n the h i n d m a r g i n , but not by a s e r i e s o f v e i n l e t s ; h i n d wing w e l l d e v e l o p e d ; c o s t a l p r o j e c t i o n low; Of of Rs w a n t i n g ; f o r c e p s w i t h a s i n g l e s h o r t t e r m i n a l j o i n t ; t a i l s t h r e e . Nymph: No m a n d i b u l a r t u s k s ; p a i r e d s p i n e s o f t e n p r e s e n t d o r s a l l y on head, t h o r a x , and/or abdomen; f o r e l e g s w i t h a s p a r s e row of s e t a e on the i n n e r s u r f a c e s ; a l l c l a w s s i m i l a r ; no g i l l t u f t s on m a x i l l a e or f o r e coxae; g i l l s exposed, p r e s e n t on segments 3r7 o r 4-7; a r u d i m e n t a r y g i l l i s o f t e n p r e s e n t on segment 1; g i l l s on segments 3 or 4 may be s i m i l a r to the f o l l o w i n g g i l l s , o r may be e l y t r o i d o r s e m i - e l y t r o i d ; t a i l s t h r e e , a l l f r i n g e d on both s i d e s . GENUS EPHEMERELLA WALSH E p h e m e r e l l a , Needham, 1935, The B i o l o g y of M a y f l i e s , 562 Edmunds & A l l e n , 1959, Ann. E n t . Soc. Amer,, 52:543-546 ( B i b l i o g r a p h y ) A d u l t : S m a l l to medium s i z e d , u s u a l l y brownish m a y f l i e s ; eyes o f male d i v i d e d , s m a l l e r l o w e r p o r t i o n d a r k e r - t h a n the l a r g e r upper p o r t i o n ; eyes u s u a l l y c l o s e l y a p p r o x i m a t e d a p i c a l l y ; eyes o f female s m a l l e r , not d i v i d e d , w e l l s e t out on. the s i d e s o f the head; o c c i p i t a l margin s t r a i g h t between the eyes; pronotum u s u a l l y w i t h a median c a r i n a ; h i n d t a r s u s s h o r t e r than the t i b i a ; 2nd and 3rd t a r s a l j o i n t s sub-e q u a l ; h i n d wing w i t h a s l i g h t rounded c o s t a l p r o j e c t i o n , beyond which i s a v e r y s h a l l o w d e p r e s s i o n i n the c o s t a l m a r g i n ; IYI o f h i n d wing f o r k e d s l i g h t l y l e s s than h a l f w a y from base; f o r c e p s 3 - j o i n t e d , -168-the 2nd j o i n t b e i n g the l o n g e s t ; penes w i t h or w i t h o u t minute s p i n e s ; a p i c a l margin o f f o r c e p s base e n t i r e ; a p i c a l margin o f s u b a n a l p l a t e of female u s u a l l y o b t u s e l y rounded, but may be e m a r g i n a t e . A l l e n and Edmunds (Edmunds, 1959), i n t h e i r r e v i s i o n of the genus E p h e m e r e l l a , have d i v i d e d t h i s genus i n t o a number of subgenera, of which n i n e a re found i n N o r t h America. Of t h e s e , f i v e a r e r e p -r e s e n t e d t o date i n B r i t i s h C o l u mbia. T h e i r d i s t i n g u i s h i n g c h a r a c t e r i s t i c s a r e as f o l l o w s : Subgenus C a u d a t e l l a Edmunds (Male) L a t e r a l t a i l s l / 4 to 3/4 as l o n g as the median t a i l . Genotype: E p h e m e r e l l a h e t e r o c a u d a t a McD Subgenus P r u n e l l a Needham ( M a l e ) Inner margin of 2nd j o i n t of f o r c e p s d i s t i n c t l y i n c u r v e d o r s t r o n g l y bowed; t e r m i n a l segment of f o r c e p s more than t w i c e as l o n g as wide, but l e s s than 4 t i m e s as l o n g ; a l l t a i l s s u b e q u a l . Genotype: E p h e m e r e l l a d o d d s i Needham Subgenus S e r r a t e l l a Edmunds (M a l e ) P o s t e r o - l a t e r a l s p i n e s on segments 8 and 9 p o o r l y d e v e l o p e d or w a n t i n g ; t e r m i n a l j o i n t o f f o r c e p s l e s s t h a n t w i c e as l o n g as wide; penes e i t h e r w i t h d o r s a l o r v e n t r a l s p i n e s o r s u b a p i c a l t u b e r c l e s , the a p i c a l notch- deep, or penes as wide or w i d e r a t apex than a t base; p e n i s l o b e s u s u a l l y b e a r i n g a s u b a p i c a l l a t e r a l t u b e r c l e on each l o b e , i f l a c k i n g , no t u b e r c l e p r e s e n t between f o r c e p s b a s e s ; a l l t a i l s s u b e q u a l . Genotype: E p h e m e r e l l a s e r r a t a Morgan Subgenus Timpanoqa Needham (M a l e ) V e s t i g i a l g i l l s on abdominal segments 4-7; w s l l - d e v e l o p e d p o s t e r o - l a t e r a l s p i n e s on t e r g i t e s 8 and 9; t e r m i n a l segment of -169-f o r c e p s l e s s than t u i i c e as l o n g as broad; a l l t a i l s s u b e q u a l i n l e n g t h . Genotype; .Ephemerella hecuba Eaton Nymph; . .  There i s a g r e a t v a r i a t i o n i n form i n t h e s e nymphs; some a r e s l e n d e r and s t r e a m l i n e d , and o t h e r s a r e f l a t t e n e d v e n t r a l l y and convex d o r s a l l y , w i t h broad f l a t t e n e d femora; some bear d o r s a l t u b e r c l e s or p a i r e d s p i n e s on the head, t h o r a x , abdomen, and l e g s ; some a r e smooth, and o t h e r s d e n s e l y c o v e r e d w i t h h a i r s ; labrum i s w i d e r than l o n g ; no m a n d i b u l a r t u s k s ; m a x i l l a e c o n i c a l a t a p i c e s , w i t h one o r more broad t e r m i n a l s p i n e s ; m a x i l l a r y p a l p i r u d i m e n t a r y or w a n t i n g , at most as l o n g as g a l e a - l a c i n i a ; l a b i a l p a l p i s h o r t ; no g i l l t u f t s on m a x i l l a e or f o r e coxae; no s e t a e on a n t e r o - l a t e r a l a n g l e s of the head; f o r e l e g s w i t h o u t a dense row of s e t a e on i n n e r s u r f a c e s ; t a r s a l c l a w s u s u a l l y d e n t i c u l a t e ; a bdominal t e r g i t e s u s u a l l y have l a t e r a l e x t e n s i o n s b e a r i n g p o s t e r o - l a t e r a l s p i n e s ; g i l l s exposed, d o r s a l i n p o s i t i o n ; i f g i l l on segment 4 i s f u l l y o p e r c u l a t e , t h e r e i s u s u a l l y a s h o r t g i l l r u d i m e n t on segment 1; t a i l s u s u a l l y as l o n g as the body, o f t e n h a i r y , or w i t h w h o r l s of s p i n e s at the j o i n i n g s , o f t e n h e l d u p r i g h t o r a r c h e d o v e r the abdomen; the d i s t i n g u i s h i n g c h a r a c t e r i s t i c of the B r i t i s h C olumbia subgenera a r e as f o l l o w s : Subgenus C a u d a t e l l a Edmunds G i l l s on abdominal segments 3-7; l a t e r a l t a i l s l / 4 t o 3/4 as l o n g as the median t a i l . Subgenus P r u n e l l a Needham D i s t i n c t t u b e r c l e s and/or s p i n e s u s u a l l y p r e s e n t on the a n t e r i o r -170-m argins of the f o r e femora; i f a b s e n t , the abdomen b e a r s an a d h e s i v e d i s c o f h a i r s v e n t r a l l y , ' o r the head, t h o r a x , and abdomen bear d i s t i n c t p a i r e d d o r s a l s p i n e s ; g i l l s on abdominal segments 3-7; a l l t a i l s s u b e q u a l i n l e n g t h . Subgenus E u r y l o p h e l l a T i e n s u u No m a x i l l a r y p a l p i ; t a r s a l c l a w s d e n t i c u l a t e ; p a i r e d abdominal t u b e r c l e s on t e r g i t e s 1-3 b l u n t ; l a m e l l a t e g i l l s on abdominal segments 4-7, the g i l l s on segment 4 s e m i - o p e r c u l a t e ; r u d i m e n t a r y g i l l s on segment 1; abdominal segment 9 l o n g e r than segment 8. Subgenus S e r r a t e l l a Edmunds No p a i r e d d o r s a l s p i n e s on head and t h o r a x , but they a re u s u a l l y p r e s e n t on the abdomen; d i s t i n c t t u b e r c l e s o r s p i n e s a b s e nt on a n t e r i o r margins of f o r e femora; abdomen w i t h no a d h e s i v e d i s c ; g i l l s on abdominal segments 3-7; g i l l s i m b r i c a t e ; g i l l on segment 3 not o p e r c u l a t e or s e m i - o p e r c u l a t e ; t a i l s s u b e q u a l i n l e n g t h , a w h o r l of s p i n e s o r h a i r - l i k e s p i n e s a t j o i n i n g s o f the segments of the median t a i l . Subgenus Timpanoqa Needham A broad e n t i r e f r o n t a l s h e l f on head; each femur p r o l o n g e d a p i c a l l y i n t o a sharp a c u t e s p i n e ; g i l l s on abdominal segments 4 t o 7 o n l y , o f t e n a r u d i m e n t a r y g i l l on segment 1; g i l l s on 4 t h segment o p e r c u l a t e ; body f l a t and wide, the w i d t h of the 5 t h abdominal segment b e i n g 2/3 to 3/4 the l e n g t h of the e n t i r e abdomen. EPHEfOERELLA  Key To A d u l t s 1. S p i n e - l i k e t o o t h a t apex of f o r e t r o c h a n t e r . . . h e c u b a hecuba Eaton No d i s t i n c t s p i n e on apex of f o r e t r o c h a n t e r 2. 2. 3 r d j o i n t o f f o r c e p s a t l e a s t t w i c e as l o n g as wide 3. -171-3rd j o i n t o f f o r c e p s s c a r c e l y l o n g e r t h a n w i d e , 8. 3. 2nd j o i n t o f f o r c e p s s t r o n g l y bowed, w i t h a deep c o n s t r i c t i o n near the m i d d l e . . . . d o d d s i Needham 2nd j o i n t of f o r c e p s not. s t r o n g l y bowed, and w i t h no 'deep c o n s t r i c t i o n near base 4. 4. UJing v e n a t i o n p a l e f l a v i l i n e a IYlcD UJing v e n a t i o n dark or y e l l o w , 5. 5. UJing v e n a t i o n y e l l o w , c r o s s v e i n s p a l e l o d i lYIayo UJing v e n a t i o n d a r k . , . 6. 6. S u b g e n i t a l " p l a t e between bases o f f o r c e p s not produced and w i t h o n l y a s h a l l o w e m a r g i n a t i o n . . q r a n d i s inqens IYlcD S u b g e n i t a l p l a t e between bases of f o r c e p s produced and w i t h a broad U-shaped e m a r g i n a t i o n . . . 7. 7. T a i l s brown c o l o r g d e n s i s Dodds T a i l s b l a c k . s p i n i f e r a Needham 8. L a t e r a l a p i c a l margins of penes p r o j e c t i n g ,forward as d i s t i n c t p r o c e s s e s , u s u a l l y s e v e r a l t o many s p i n e s on t h e penes..,9. L a t e r a l a p i c a l m a r gins of the penes rounded, and w i t h no f o r w a r d p r o j e c t i n g p r o c e s s e s . S p i n e s , i f p r e s e n t , b a r k - l i k e and d o r s o - l a t e r a l i n p o s i t i o n 13. 9. L a t e r a l a p i c a l p r o c e s s e s of the penes s h o r t , b l u n t and d i r e c t e d i n w a r d s . The a p i c a l n o t c h between the penes r e l a t i v e l y s h a l l o w 10. L a t e r a l a p i c a l p r o c e s s e s of the penes r a t h e r l o n g and s l e n d e r , d i r e c t e d f o r w a r d or outward. The a p i c a l n o t c h between the penes deeper.... 11. -172-10. 2nd j o i n t o f f o r c e p s not d i s t i n c t l y s w o l l e n a p i c a l l y . . , t i n e r m i s Eaton 2nd j o i n t of f o r c e p s ' d i s t i n c t l y s w o l l e n a p i c a l l y . . . i n f requens IYlcD 11. Abdominal s t e r n a u n i f o r m l y dark brown w i t h p a l e l a t e r a l margins on segments 8 and 9....'. j a c o b i IYlcD Abdominal s t e r n a each w i t h a s h a l l o w dark brown' chevron o r w i t h 3 brown l o n g i t u d i n a l s t r i p e s . . . .. ..12. 12'. Abdominal s t e r n a each w i t h a s h a l l o w dark brown c h e v r o n ....... '.'...' . ' . . . . . . . . . . h y s t r i x T r a v e r Abdominal s t e r n a each w i t h t h r e e brown l o n g i t u d i n a l s t r i p e s . '. . .". . . . . . he-terocaudata IYlcD 13. Thorax b l a c k i s h . V e n a t i o n p a l e grey-brown, c r o s s v e i n s d i s t i n c t . Abdominal segments of male t r a n s l u c e n t w h i t i s h on the a n t e r i o r margins .• . t i b i a l i s IYlcD Thorax c h o c o l a t e brown. L o n g i t u d i n a l v e i n s l i g h t brown, c r o s s -v e i n s and i n t e r c a l a r i e s p a l e . Abdominal t e r g i t e s brown... '..14. 14. Abdominal t e r g i t e s u n i f o r m l y brown sp. 1 Abdominal t e r g i t e s brown, e x c e p t the p o s t e r i o r margin of each t e r g i t e dark brown . t e r e s a T r a v e r Key To IMymphs 1. G i l l s on abdominal segments 4 to 7. .....2. G i l l s on ab d o m i n a l segments 3 t o 7 3. 2. G i l l on segment 4 o p e r c u l a t e . D o r s a l s p i n e s o b s o l e s c e n t . No , g i l l on segment 1 ..hecuba hecuba Eaton G i l l on segment 4 s e m i - o p e r c u l a t e . D o r s a l s p i n e s on segment .1-10,moderately l o n g on segments 1-8, s h o r t and b l u n t on -173-segment 9, b a r e l y d i s c e r n i b l e on segment 10. Rudimentary g i l l on segment 1 . l o d i ITlayo 3. D o r s a l abdominal s p i n e s w a n t i n g . 4. D o r s a l abdominal s p i n e s p r e s e n t 6. 4. Teeth o r s p i n e s p r e s e n t on a n t e r i o r margin of f o r e femur....... d o d d s i Needham No t e e t h o r s p i n e s on a n t e r i o r margin o f f o r e femur .5. 5. • E n t i r e l a t e r a l m argin o f pronotum p a l e . L a t e r a l e x t e n s i o n s o f abdominal segments marked w i t h a dark median t r a n s v e r s e band. P a l e submedian s p o t s p r e s e n t on p o s t e r i o r margins of abdominal t e r g i t e s . 8 t e e t h on c l a w s . P i g m e n t a t i o n on upper p l a t e o f g i l l on segment 3 heavy i n e r m i s Eaton No d i s t i n c t p a l e m a r k i n g s on pronotum. No dark band on l a t e r a l e x t e n s i o n s o f abdominal segments. No p a l e submedian s p o t s • on p o s t e r i o r margins of t e r g i t e s , 5 - 6 t e e t h on c l a w s . P i g m e n t a t i o n o f upper p l a t e o f g i l l on segment 3 none or s l i g h t , i n f r e q u e n s fflcD 6. T e e t h oc s p i n e s p r e s e n t on a n t e r i o r margin o f f o r e femur..-..7. Teeth or s p i n e s w a n t i n g on a n t e r i o r margin o f f o r e femur, 8. 7. "Thumb" at d i s t a l end of f o r e t i b i a l o n g and s h a r p . Femora s l e n d e r . D o r s a l s p i n e s on segments 1-9 ., E o l o r a d e n s i s Dodds "Thumb" a t d i s t a l end of f o r e t i b i a s h o r t and b l u n t . Femora s t o u t . D o r s a l abdominal s p i n e s on segment 2-9 f l a v i l i n e a PflcD 8. L a t e r a l c e r c i l / 4 t o 3/4 as l o n g as the median t e r m i n a l f i l a m e n t s , . »9« -174-L a t e r a l c e r c i s u b e q u a l to t e r m i n a l , f i l a m e n t s * ,10. 9. M a x i l l a r y p a l p weak. A w h o r l of s p i n e s a t each t a i l j o i n i n g . . . , , . h e t e r o c a u d a t a McD M a x i l l a r y p a l p n o r m a l l y d e v e l o p e d . T a i l s may have w h o r l s o f s p i n e s i n the' b a s a l h a l f , ' f r i n g e d w i t h l o n g h a i r s i n a p i c a l p o r t i o n . h y s t r i x T r a v e r 10. T h o r a c i c t u b e r c l e s p r e s e n t 11. No t h o r a c i c t u b e r c l e s . ......12. 11. Submedian s p i n e o f pronotum, i f p r e s e n t , l a r g e and b l u n t , i n groups of 3. S u b m a r g i n a l p r o n o t a l s p i n e s s h o r t and b l u n t . . . q r a n d i s i n q e n s McD Submedian s p i n e o f pronotum r a t h e r s l e n d e r , s h a r p - p o i n t e d , 2 i n each group. S u b m a r g i n a l p r o n o t a l s p i n e s s h a r p at t i p s , w e l l d e v e l o p e d . s p i n i f e r a Needham 12. D o r s a l s p i n e s on abdominal segments 2 to 9. 7 t e e t h on c l a w s . No v e n t r a l m a r k i n g s , t i b i a l i s McD D o r s a l s p i n e s on segments 4 to 7. 9-10 t e e t h on c l a w s . Abdominal s t e r n a l l i g h t brown w i t h p a i r e d s u b l a t e r a l dark brown s t r e a k s ' t e r e s a T r a v e r s Unknown: E. j a c o b i McD EPHEMERELLA C0L0RADENSIS DODDS E p h e m e r e l l a c o l o r a d e n s i s Dodds, A l l e n and Edmunds, 1962, M i s c . Pub. Ent . Soc. Amer. 3 (5) : 157 ( B i b l i o g r a p h y A d u l t : T h i s s p e c i e s i s a member o f the subgenus P r u n e l l a . A dark brown or b l a c k i s h m a y f l y of moderate s i z e ; t h o r a x dark brown; no d i s t i n c t s p i n e s on the a p i c e s o f the f o r e t r o c h a n t e r s ; wing v e n a t i o n dark -175-p u r p l i s h brown; abdominal t e r g i t e s u n i f o r m dark brown w i t h p a l e m a r g i n s ; p l e u r a l f o l d p a l e ; s t e r n i t e s dark brown; s u b g e n i t a l p l a t e between bases of f o r c e p s produced and w i t h a broad U-shaped emarg-i n a t i o n ; a p i c a l margin o f f o r c e p s base almost s t r a i g h t ; 2nd j o i n t o f f o r c e p s may be s t r o n g l y bowed, but w i t h o u t a deep c o n s t r i c t i o n , o r m o d e r a t e l y and r e g u l a r l y c u r v e d , but not s w o l l e n near apex and t h i n n e r i n the m i d d l e ; 3 r d j o i n t a t l e a s t t w i c e as l o n g as wide; penes w i t h a U-shaped a p i c a l median c l e f t ; l o b e s o f penes expanded a p i c a l l y ; t a i l s brown, d a r k e r a t base. Nymph: F r o n t a l Rorns and f r o n t a l s h e l f w a n t i n g ; mouthparts v i s i b l e a n t e r i o r l y , genae not produced i n t o f l a n g e s or p r o j e c t i o n s ; head roughened, o c c i p u t o n l y roughened or b e a r i n g low, b l u n t , i n c o n s p i c u o u s t u b e r c l e s ; no s p i n e s o r t u b e r c l e s on pronotum or metanotum, o n l y a v e r y s h o r t median p o s t e r i o r t u b e r c l e on mesonotum; a n t e r i o r margins of f o r e femora w i t h t e e t h o r s p i n e s ; none on m i d d l e or h i n d femora; l e g s s t o u t , but more s l e n d e r than i n E. f l a v i l i n e a ; femora f l a t t e n e d , the p o s t e r i o r margins w i t h many h a i r s and a few s h o r t s p i n e s ; "thumb" a t d i s t a l end of f o r e t i b i a l o n g , s h a r p , and r e l a t i v e l y s t r a i g h t ; g i l l s on abdominal segments 3-7; no e l y t r o i d g i l l s ; p i g m e n t a t i o n of the upper p o r t i o n o f g i l l on segment 3 i s heavy and i n a w e l l -d e f i n e d 2 o r 3-lobed a r e a ; lower p o r t i o n o f t h i s g i l l has a p p a r e n t l y 3 l a y e r s of secondary l o b e s which a re broad o v a l o r s p a t u l a t e ; g i l l on segment 7. i s about l / 5 the l e n g t h o f the g i l l on segment 3; g i l l on segment 3 o v e r l a p s the one f o l l o w i n g by l / 3 or l e s s of i t s l e n g t h ; p a i r e d d o r s a l s p i n e s on t e r g i t e s 1-9, l o n g e r on t e r g i t e s 6-8; d o r s a l s p i n e s on these t e r g i t e s f a i r l y w e l l d e v e l o p e d ; s p i n e s on t e r g i t e 9 l o n g and s h a r p ; i f o c c i p i t a l t u b e r c l e s p r e s e n t , s p i n e s on t e r g i t e 9 -176-more a c u t e ; g e n e r a l c o l o u r l i g h t brown, m o t t l e d w i t h p a l e r , e s p e c i a l l y on the l e g s ; s t e r n i t e s may have s p a r s e h a i r s , but never an a d h e s i v e d i s c ; t a i l s each w i t h two dark and two p a l e r bands. D i s t r i b u t i o n ; C o l o r a d o , Montana, Wyoming, Ut a h , B r i t i s h C olumbia No specimens of t h i s s p e c i e s were examined. EPHEMERELLA DODDSI NEEDHAM E p h e m e r e l l a d o d d s i Needham, A l l e n and Edmunds, 1962, M i s c . Pub. E n t . Soc. Amer. 3 (5) : 163 ( B i b l i o g r a p h y ) A d u l t ; T h i s s p e c i e s i s p l a c e d i n the subgenus P r u n e l l a ; head and t h o r a x dark r e d d i s h - b r o w n ; f o r e femora dark p u r p l i s h brown, r e s t o f l e g p a l e r ; m i d d l e and h i n d l e g s y e l l o w i s h , femora shaded w i t h brown w i t h no dark a p i c a l bands; the t h r e e b a s a l t a r s a l j o i n t s shaded w i t h p u r p l i s h b l a c k ; no d i s t i n c t s p i n e on apex of f o r e t r o c h a n t e r ; wings h y a l i n e ; v e n a t i o n dark b rown; abdominal t e r g i t e s each w i t h a broad median t r a n s v e r s e dark brown band, p a l e r on d o r s a l a r e a s ; a n t e r i o r and p o s t e r i o r margins w i d e l y p a l e ; p l e u r a l f o l d p a l e ; s t e r n i t e s dark; 2nd j o i n t of f o r c e p s s t r o n g l y bowed w i t h a deep c o n s t r i c t i o n near the m i d d l e ; 3 r d f o r c e p s j o i n t a t l e a s t t w i c e as l o n g as wide; l o b e s of penes c o n s t r i c t e d a p i c a l l y ; t a i l s dark brown b a s a l l y , becoming p a l e a p i c a l l y . Nymph: A y e l l o w i s h t o t a n s p e c i e s ; d a r k e r on eyes , g i l l s , wing pads and bases o f t a i l s and t a r s i ; no f r o n t a l h o r n s ; a broad f r o n t a l s h e l f , notched to r e c e i v e the bases o f the antennae; o c c i p i t a l t u b e r c l e s w a n t i n g ; no t h o r a c i c s p i n e s or t u b e r c l e s ; t e e t h o r s p i n e s p r e s e n t on a n t e r i o r margins o f f o r e femora; s m a l l e r s p i n e s on p o s t e r i o r m a r g i n s . o f f o r e femora and both margins of o t h e r femora; a l l femora f l a t t e n e d ; t i b i a l "thumb" on f o r e l e g l / 3 as l o n g as t h e t a r s u s , s t r o n g , sharp a t t i p , and d i r e c t e d o u t w a r d l y ; no d o r s a l a b dominal s p i n e s ; abdominal t e r g i t e s shaded w i t h brou/n; g i l l s on abdominal segments 3-7; g i l l on segment 3 o v e r l a p s the one f o l l o w i n g by l / 3 i t s l e n g t h o r l e s s , but not e l y t r o i d ; upper p o r t i o n o f g i l l on segment 3 i s h e a v i l y pigmented i n a w e l l - d e f i n e d 2 o r 3-lobed a r e a ; s e c o n d a r y l o b e s o f l o w e r p o r t i o n o f g i l l on segment 3 w i t h 2 l a y e r s , broad o v a l o r s p a t u l a t e ; g i l l on segment 7 about l / 5 the l e n g t h o f the g i l l on segment 3; v e n t e r of the abdomen b e a r i n g an a d h e s i v e d i s c of l o n g h a i r s on i t s o u t e r margin and s h o r t h a i r s i n i n n e r space, e x t e n d i n g from s t e r n i t e s 1 t o 9; t a i l s y e l l o w i s h , d a r k e r b a s a i l y , l i g h t brown a p i c a l l y , s h o r t . E c o l o g y : Nymphs of t h i s s p e c i e s were taken from the m i d d l e o f f o u r l o c a t i o n s on the A l o u e t t e R i v e r , a t depths of 1 to 3 f e e t . The s u b s t r a t e c o n s i s t e d o f sand, g r a v e l , r o c k s , b o u l d e r s , and bed r o c k . The c u r r e n t , e x c e p t i n one case o f q u i e t r i p p l e s , was r a p i d . They were c o l l e c t e d the year round. D i s t r i b u t i o n ; Utah, Washington,.Montana, C o l o r a d o , C a l i f o r n i a , New M e x i c o , Wyoming, B r i t i s h C olumbia. M a t e r i a l Examined; 2 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Hane y), VI.2.59 (N.3. F i l m e r ) , 26 Nymphs, B r i t i s h C o l u m b i a : Loon Creek ( C l i n t o n ) , VI.16.56 (H. L o r z ) , 19 Nymphs, B r i t i s h C o l u m b i a : Loon Cr. ( C l i n t o n ) VI.13.? (H. L o r z ) . -178-EPHEIY1ERELLA FLAUILINEA IflcDUNNOUGH E p h e m e r e l l a f l a v i l i n e a McPunnough, A l l e n and Edmunds, 1962, M i s c . Pub. E n t . Soc. Amer., 3 (5) : 159 ( B i b l i o g r a p h y ) A d u l t : T h i s s p e c i e s b e l o n g s t o the subgenus P r u n e l l a ; a s m a l l m a y f l y ; head and t h o r a x deep ruddy brown; f o r e femora and t i b i a e deep b l a c k i s h brown, t a r s i w h i t i s h ; m i d d l e and h i n d l e g s d u l l y e l l o w i s h , a r e d d i s h brown a p i c a l p a t c h on i n n e r s u r f a c e of each femur; no b l a c k d o t s on femora; no d i s t i n c t s p i n e on apex o f f o r e t r o c h a n t e r ; wings h y a l i n e ; v e n a t i o n p a l e ; abdominal t e r g i t e s deep ruddy brown; p l e u r a l f o l d marked by a y e l l o w i s h l i n e e x t e n d i n g upwards i n each segment, e s p e c i a l l y i n the a p i c a l segments; s t e r n i t e s more r e d d i s h ; s u b g e n i t a l p l a t e between f o r c e p s bases not produced and w i t h o n l y a s h a l l o w e m a r g i n a t i o n ; 2nd f o r c e p s j o i n t ' s l i g h t l y bowed, or may be s t r o n g l y bowed, w i t h a deep c o n s t r i c t i o n near the apex; t i p of f o r c e p s bent i n w a r d ; 3 r d j o i n t o f f o r c e p s a t l e a s t t w i c e as l o n g as wide; a p i c a l l a t e r a l margins and l o b e s of penes expanded a p i c a l l y ; t a i l s b l a c k b a s a l l y , p a l e r a p i c a l l y . Nymph: A l i g h t t o dark brown nymph, i f l i g h t t h e y are d i s t i n c t l y m o t t l e d ; f r o n t a l horns w a n t i n g ; no f r o n t a l s h e l f , t h e mouthparts v i s i b l e a n t e r i -o r l y , and the genae not produced i n t o f l a n g e s or p r o j e c t i o n s ; p a i r e d o c c i p i t a l t u b e r c l e s u s u a l l y s h o r t and b l u n t , but may be m o d e r a t e l y l o n g and s h a r p ; no t h o r a c i c s p i n e s or. t u b e r c l e s ; l e g s s t o u t e r , f o r e t i b i a e s l e n d e r ; a n t e r i o r margin of f o r e femora w i t h t e e t h or s p i n e s ; o t h e r femora l a c k i n g such s p i n e s or t u b e r c l e s ; t i b i a l "thumbs" a t apex of f o r e t i b i a e s h o r t and b l u n t : femora w i t h t h r e e p a l e i n d i s t i n c t a r e a s ; t i b i a e w i t h d i s t i n c t p a l e bands a t each end; t a r s i banded i n -179-the m i d d l e ; d o r s a l a bdominal s p i n e s on segments 2-9, v e r y s m a l l on t e r g i t e 9; i f o c c i p i t a l t u b e r c l e s l o n g and s h a r p , abdominal s p i n e s on segment 9 m o d e r a t e l y l o n g ; a n d s h a r p : abdominal s p i n e s s h o r t ; g i l l s on a bdominal segments 3-7; g i l l on segment 3 o v e r l a p s the f o l l o w i n g one l / 3 i t s l e n g t h or l e s s , not e l y t r o i d ; p i g m e n t a t i o n of upper p o r t i o n of g i l l on-segment 3 i s heavy and i s of 1 l o b e ; secondary l o b e s of lower p o r t i o n of g i l l on segment 3 are e l l i p t i c a l t o s p a t u l a t e w i t h no b a s a l t h u m b - l i k e l o b e ; g i l l on segment 7 i s l / 5 the l e n g t h of t h a t on segment 3; t a i l s p a l e : w i t h narrow b l a c k i s h bands beyond the m i d d l e and a t the t i p s . E c o l o g y ; Nymphs of t h i s s p e c i e s were t a k e n from the m i d d l e and edges of many l o c a t i o n s on the A l o u e t t e R i v e r , ' a l w a y s a t a depth of 1 t o 2 f e e t . ' The stream bed v a r i e d from s i l t , t h r o u g h mud, sand, g r a v e l , r o c k s , b o u l d e r s , to bedrock; the c u r r e n t v a r i e d from q u i e t water to r a p i d s and f a l l s . They were c o l l e c t e d d u r i n g the e n t i r e y e a r . D i s t r i b u t i o n : Montana, Wyoming, A l b e r t a , B r i t i s h C o l u mbia. M a t e r i a l Examined: 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), VI.19.59 (N.3. F i l m e r ) , 2 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney) . V.26.59 (N.G. F i l m e r , 12 Nymphs, B r i t i s h C o l u m b i a : nr H e l l ' s Gate, VI.19.59 (G.G.E. Scudder) EPHEMERELLA GRANDIS INGEN5 McDUNNOUGH E p h e m e r e l l a q r a n d i s inqens McDunnough, A l l e n and Edmunds, 1962, M i s c . Pub. E n t . Soc. Amer. A d u l t : ' 3 (5) : 175 ( B i b l i o g r a p h y ) A b l a c k i s h m a y f l y b e l o n g i n g t o the subgenus P r u n e l l a ; head and t h o r a x b l a c k , l a t e r a l and p o s t e r i o r margins of mesonotum shaded s l i g h t l y w i t h brown, and a s l i g h t y e l l o w s h a d i n g on the median a r e a of the -180-metanotum; f o r e l e g s b l a c k i s h , w i t h the margins o f the femora near •.bases t i n g e d w i t h a p a l e smoky y e l l o w ; femora o f m i d d l e and h i n d l e g s b l a c k i s h t i n g e d w i t h y e l l o w i s h a t bases and on m a r g i n s , r e s t y e l l o w i s h ; no d i s t i n c t s p i n e on apex o f f o r e t r o c h a n t e r ; wings h y a l i n e , the f o r e w i n g s u f f u s e d w i t h l i g h t amber i n b a s a l p o r t i o n ; v e n a t i o n b l a c k brown; s t i g m a t i c c r o s s v e i n s i n d i s t i n c t ; p o s t e r i o r f o r k of ffl n ot f u s e d w i t h C u l ; abdominal t e r g i t e s smoky y e l l o w or y e l l o w - b r o w n , each of t e r g i t e s 2-7 w i t h a l a r g e median q u a d r a t e b l a c k or deep p u r p l i s h brown p a t c h and l a t e r a l c i r c u l a r p a t c h e s of the same c o l o u r ; i n . a p i c a l segments the dark p a t c h e s more or l e s s c o a l e s c e ; s t e r n i t e s w i t h broad l i g h t y e l l o w - b r o w n p o s t e r i o r m a r g i n s , remainder b l a c k i s h w i t h a r e d d i s h t i n g e and f a i n t t r a c e s of s m a l l o b l i q u e submedian p a l e s t r e a k s on the a n t e r i o r m a r g i n s ; s u b g e n i t a l p l a t e between the f o r c e p s bases not produced and w i t h o n l y a s h a l l o w e r n a r g i n a t i o n ; 2nd f o r c e p s j o i n t not bowed and c o n s t r i c t e d , but i s i r r e g u l a r l y s w o l l e n ; 3 r d f o r c e p s j o i n t at l e a s t t w i c e as l o n g as wide; a p i c a l l a t e r a l margins of penes not expanded, the s i d e s n e a r l y bowed; l o b e s of penes expanded a p i c a l l y ; t a i l s b l a c k . Nymph; No f r o n t a l horns or f r o n t a l s h e l f ; o c c i p i t a l t u b e r c l e s l o n g ; submedian s p i n e s of pronotum i n groups of 3, l a r g e and b l u n t , p o s t e r i o r s p i n e o f each group s h o r t ; s u b m a r g i n a l s p i n e s o f pronotum s h o r t and b l u n t ; mesothorax w i t h 1 or 2 submedian p a i r s of t u b e r c l e s which are w e l l d e v e l o p e d and b l u n t to sharp,- and a s i n g l e m e d i a n . p o s t e r i o r t u b e r c l e ; submedian m e s o t h o r a c i c t u b e r c l e s may be j u s t a p a i r of submedian r i d g e s ; no t e e t h or s p i n e s on a n t e r i o r margins of f o r e femora; margins o f f o r e femora w i t h o n l y s c a t t e r e d h a i r s , not a r r a n g e d i n a m a r g i n a l row; l a t e r a l margins of a b d o m i n a l t e r g i t e s d i s t i n c t l y -181-convex; abdominal d o r s a l s p i n e s i n a r e g u l a r s e r i e s , f a i r l y c l o s e t o g e t h e r , t h o s e on segments 8 and 9 l a r g e r than the o t h e r s ; g i l l s on segments 3-7. D i s t r i b u t i o n : B r i t i s h C olumbia M a t e r i a l Examined: 1 Nymph, B r i t i s h C o l u m b i a : Loon Creek ( C l i n t o n ) , VI.16.56 (H. L o r z ) 2 Nymphs, B r i t i s h C o l u m b i a : Loon Creek ( C l i n t o n ) , VI.13.? (H. L o r z ) EPHEMERELLA HECUBA HECUBA EATON E p h e m e r e l l a hecuba hecuba E a t o n , Edmunds and A l l e n , 1959, Can. E n t . 91:54 ( B i b l i o g r a p h y ) A d u l t : T h i s s p e c i e s b e l o n g s t o the subgenus Timpanoqa; head m o t t l e d brown w i t h w h i t i s h m a r g i n s ; pronotum m o t t l e d brown, c a r i n a e r e d d i s h ; a n t e r i o r median p o r t i o n o f mesonotum brown, p o s t e r i o r p o r t i o n r e d d i s h brown; metanotum l i g h t y e l l o w ; f o r e t r o c h a n t e r w i t h a s p i n e - l i k e t o o t h a t i t s apex; f o r e femora dark brown w i t h b l a c k i s h m a r g i n s ; f o r e t i b i a e c u r v e d , n o t c h e d b a s a i l y on the a n t e r i o r m a r g i n s ; wings s e m i - h y a l i n e ; v e n a t i o n d i s t i n c t ; abdominal t e r g i t e s 1-4 dark y e l l o w , each w i t h a t r a n s v e r s e r e d d i s h s t r i p e which widens l a t e r a l l y and p o s t e r i o r l y i n t o a comma-shaped mark; on e i t h e r s i d e o f the median l i n e i s a' l i g h t y e l l o w c i r c u l a r ' s p o t which, e n l a r g e s p o s t e r i o r l y ; t e r g i t e s 5-10 a r e almost e n t i r e l y c o v e r e d by the r e d d i s h bands p o s t e r i o r l y and the w h i t i s h c i r c u l a r s p o t s a n t e r i o r l y ; p e r s i s t e n t r e s p i r a t o r y g i l l s a r e borne on segments 4 to 8; t e r g i t e s 9 and 10 bear prominent p o s t e r o - l a t e r a l s p i n e s ; each s t e r n i t e i s marked by a s e m i l u n a r y e l l o w i s h p o s t e r i o r margin and r e d d i s h a n t e r i o r and l a t e r a l m a r g i n s ; f o r c e p s l i g h t y e l l o w ; 2nd j o i n t o f f o r c e p s c o n s t r i c t e d near,, the apex; 3 r d f o r c e p s j o i n t s h o r t and em a r g i n a t e p o s t e r i o r l y ; -182C-a p i c a l p o r t i o n s of the penes a r e s e p a r a t e d by an i r r e g u l a r l y U-shaped n o t c h . Nymph; Body much f l a t t e n e d and h a i r y ; head c o m p a r a t i v e l y s m a l l ; head w i t h a broad e n t i r e f r o n t a l s h e l f ; no f r o n t a l h o r n s ; pronotum w i d e s t a t p o s t e r i o r m a r g i n , a s h o r t t u b e r c l e near m i d d l e o f each l a t e r a l m argin and a p a i r of s h o r t s u b m e d i a l t u b e r c l e s near p o s t e r i o r m a r g i n ; l e g s h a i r y ; m i d d l e coxae each b e a r s a s h o r t c o n i c a l s p i n e o r t u b e r c l e on i t s d o r s a l s u r f a c e ; each femur w i t h an a c u t e s p i n e at t h e apex, and the t r a c e s o f two b l a c k i s h bands; a b l a c k i s h band near the m i d d l e of each t i b i a ; b a s a l h a l f o f each t a r s u s b l a c k i s h ; abdomen s t o u t , f l a t t e n e d , w i d e s t a t 5 t h segment; t e r g i t e s 2-9 extended l a t e r a l l y i n t o ( sharp s a w - t o o t h - l i k e p o s t e r o - l a t e r a l s p i n e s which a r e p a l e b a s a l l y , c r o s s e d beyond the bases by wide b r o w n i s h bands, and r e d d i s h brown a t t i p s ; t e r g i t e s 4-6 w i t h o b s o l e s c e n t d o r s a l s p i n e s ; a dark brown median l i n e on t e r g i t e s 3 and 4; t e r g i t e s 5-9 w i t h f a i n t sub-median bro w n i s h a r e a s , and r e d d i s h l a t e r a l s t r e a k s n e x t to g i l l s ; a n t e r i o r h a l f and much of l a t e r a l p o r t i o n s of each s t e r n i t e marked w i t h wide r e d d i s h t o b r o w n i s h bands, and f a i n t i n d i c a t i o n s of p a l e submedian o b l i q u e marks a t a n t e r i o r m a r g i n ; g i l l s on segments 4-7; g i l l on segment 4 e l y t r o i d , c o v e r i n g the next one f o r 3/4 of i t s l e n g t h ; p i g m e n t a t i o n o f upper p o r t i o n of- g i l l on segment 4 i s l i g h t o r w a n t i n g ; t a i l s w i t h one or two narrow b l a c k i s h bands b a s a l l y , a wide b l a c k band a t 2/3 the d i s t a n c e from the base, and t i p s n a r r o w l y b l a c k . D i s t r i b u t i o n : C o l o r a d o , New M e x i c o , Utah, C a l i f o r n i a , B r i t i s h C olumbia. No specimens of t h i s s p e c i e s were examined. -183- ' EPHEITIERELLA HETEROCAUDATA McDUNNOUGH E p h e m e r e l l a h e t e r o c a u d a t a McDunnough, A l l e n and Edmunds, 1961, Ann, E n t . Sac. Amer. 54:603-12 ( B i b l i o g r a p h y ) A d u l t : T h i s s p e c i e s i s a member of the subgenus C a u d a t e l l a ; an o l i v e brown m a y f l y w i t h b l a c k m a r k i n g s ; t h o r a x d a r k . o l i v e brown, pronotum w i t h c o n s i d e r a b l e b l a c k s h a d i n g ; l e g s deep o l i v e , f o r e femora and t i b i a e t i n g e d w i t h b l a c k ; no s p i n e a t apex of f o r e t r o c h a n t e r ; no dark a p i c a l markings on m i d d l e and h i n d femora; wings h y a l i n e ; l o n g i t u d i n a l v e i n s smoky, c r o s s v e i n s p a l e ; abdominal t e r g i t e s o l i v e brown, w i t h a n t e r i o r broad b l a c k bands on t e r g i t e s 1-4, and s e m i c i r c u l a r a n t e r i o r p a t c h e s of the same c o l o u r on p o s t e r i o r t e r g i t e s ; t e r g i t e s a l s o w i t h l a t e r a l b l a c k p a t c h e s which tend t o f u s e w i t h the b l a c k bands on the a n t e r i o r t e r g i t e s ; s t e r n i t e s p a l e o l i v e w i t h t h r e e i r r e g u l a r l o n g i t u d i n a l b l a c k or brown s t r i p e s ; 3 r d f o r c e p s j o i n t s c a r c e l y l o n g e r than wide; penes u n i t e d , f o r m i n g an u p curved r o d , s w o l l e n a p i c a l l y ; l a t e r a l a p i c a l margins of penes rounded, w i t h no f o r w a r d p r o j e c t i n g p r o c e s s e s ; u s u a l l y b a r b - l i k e l a t e r a l d o r s a l s p i n e s p r e s e n t on penes, one on each s i d e ; t a i l s smoky, r i n g e d , the m i d d l e one t w i c e as l o n g as the o u t e r ones. Mymph: A dark brown nymph; head and t h o r a x smooth; labrum o n l y s l i g h t l y e m a r g i n a t e on a p i c a l m a r g i n ; m a x i l l a r y p a l p i weak, 3 - j o i n t e d ; no t h o r a c i c t u b e r c l e s ; l e g s s h o r t ; femora f l a t t e n e d ; no t e e t h or s p i n e s on a n t e r i o r margin of f o r e femora, a l t h o u g h t h e r e i s a d i s t i n c t row of m a r g i n a l h a i r s ; t i b i a e and t a r s i a l s o w i t h a d i s t i n c t row of h a i r s ; c l a w s w i t h a s i n g l e row of 7 d e n t i c l e s ; l e g s not banded; abdominal t e r g i t e s marked as i n imago; p a i r e d d o r s a l abdominal s p i n e s on segments -184-2-9, p r o m i n e n t , s t r o n g , i n c u r v e d ; abdominal d o r s a l s p i n e s becoming p r o g r e s s i v e l y l o n g e r and f u r t h e r a p a r t from t e r g i t e 2 t o 7, but s h o r t e r and c l o s e r t o g e t h e r on t e r g i t e s 8 and 9; no l a t e r a l e x t e n s i o n s on p o s t e r o - l a t e r a l s p i n e s or. t e r g i t e s ; p a t t e r n on s t e r n i t e s v a r i a b l e , may be a r e d d i s h brown median s t r i p e and a l i n e o f brown submedian dashes, or s t e r n i t e s may be u n i c o l o u r e d o r w i t h l i g h t l a t e r a l d o t s or s t r e a k s ; m i d d l e t a i l . 3 t i m e s as l o n g as the o u t e r ones, b r o w n i s h , j o i n i n g s d a r k e r and w i t h w h o r l s of s p i n e s ; g i l l s on segment 3-7. D i s t r i b u t i o n : Wyoming, B r i t i s h Columbia No specimens of t h i s s p e c i e s were examined. EPHEMERELLA HYSTRIX TRAVER E p h e m e r e l l a h y s t r i x T r a v e r , A l l e n and Edmunds, 1961, Ann. Ent. Soc. Arner. 54:603-12 ( B i b l i o g r a p h y ) . A d u l t : A member of the subgenus C a u d a t e l l a ; no d i s t i n c t s p i n e a t the apex o f the f o r e t r o c h a n t e r ; each abdominal s t e r n i t e marked w i t h a s h a l l o w dark brown c h e v r o n ; 3 r d f o r c e p s j o i n t s c a r c e l y l o n g e r than wide; penes u n i t e d , s w o l l e n a p i c a l l y ; l a t e r a l a p i c a l m a r gins of penes p r o j e c t i n g f o r w a r d as d i s t i n c t p r o c e s s e s ; l a t e r a l a p i c a l p r o c e s s e s of penes l o n g and s l e n d e r , d i r e c t e d f o r w a r d o r outward; deep a p i c a l n o t c h between penes; u s u a l l y s e v e r a l to many s p i n e s on penes. Nymph: A l i g h t r e d d i s h brown s p e c i e s ; head and t h o r a x smooth; no o c c i p i t a l t u b e r c l e s on f r o n t a l s h e l f ; labrum o n l y s l i g h t l y e m a r g i nate on a p i c a l m a r g i n ; m a x i l l a r y p a l p i n o r m a l l y d e v e l o p e d , 3 - j o i n t e d ; femora s l i g h t l y f l a t t e n e d ; no t e e t h o r s p i n e s on a n t e r i o r margins o f f o r e femora; s h o r t , i n c o n s p i c u o u s s p i n e s on p o s t e r i o r margins of femora; u s u a l l y no s p i n e s on the upper s u r f a c e s o f the f o r e femora, but i f p r e s e n t , -185-they a r e g e n e r a l l y d i s t r i b u t e d and not i n a t r a n s v e r s e a p i c a l band; t i b i a e and t a r s i w i t h o u t a d i s t i n c t row of h a i r s ; c l aws w i t h a s i n g l e row of 7-8 d e n t i c l e s ; l e g s unbanded, but j o i n i n g s o f l e g s , a p i c e s o f t a r s i , and claws dark r e d d i s h brown; p a i r e d d o r s a l a bdominal s p i n e s on segments 1-9 or 2-9, c u r v e d near t i p s , and each b e a r i n g a s e r i e s o f s p i n u l e s on a n t e r i o r margin near t i p ; s p i n e s on segment 2 s h o r t , c l o s e t o g e t h e r , and becoming p r o g r e s s i v e l y l o n g e r and f u r t h e r a p a r t p o s t e r i o r l y , l o n g e s t on segments 6 and 7, which a r e s u b e q u a l ; s p i n e s on segments 8 and 9 s h o r t e r , s l i g h t l y c o n v e r g e n t ; s p i n e s on m i d d l e segments c u r v e outward; abdominal t e r g i t e s w i t h s h o r t l a t e r a l e x t e n s i o n s b e a r i n g s h o r t p o s t e r o - l a t e r a l s p i n e s on segments 4-7, t h e s e b e i n g rounded and i n c u r v e d on segments 8 and 9; b a s a l t e r g i t e s p a l e r e d d i s h brown, becoming d a r k e r p o s t e r i o r l y , w i t h no p a l e d o r s a l s t r i p e , but t r a c e s of a dark median l i n e on segments 7 and 8, and dark submedian s t r e a k s on the p r e c e d i n g t e r g i t e s , and w i t h l a r g e dark l a t e r a l p a t c h e s on t e r g i t e s 8 and 9, and beneath g i l l s on o t h e r segments; abdominal s t e r n i t e s v a r i a b l e , may be u n i c o l o u r e d , or w i t h p a l e l a t e r a l d o t s o r s t r e a k s , or marked w i t h dark chevron-shaped m a r k i n g s , or each s t e r n i t e w i t h two broad l a t e r a l dark r e d d i s h brown t r i a n g l e s which a r e c o n n e c t e d on the a n t e r i o r m a r g i n ; g a n g l i o n i c a r e a s of s t e r n i t e s 1-6 p a l e , o f 7-8 dark brown; t a i l s unbanded; f r i n g e d w i t h l o n g h a i r s i n a p i c a l p o r t i o n , may have w h o r l s of s p i n e s a t j o i n i n g s i n b a s a l h a l f ; g i l l s on segments 3-7. E c o l o g y ; Nymphs of t h i s s p e c i e s have been ta k e n from the m i d d l e and edge of one l o c a t i o n on the A l o u e t t e R i v e r , at a depth o f 1-2 f e e t . The stream-bed c o n s i s t e d o f mud, g r a v e l , r o c k s , and b o u l d e r s . The c u r r e n t was r a p i d i n the m i d d l e , and q u i e t on the edge. They were c o l l e c t e d i n June. -186-D i s t r i b u t i a n ; Montana, B r i t i s h Columbia M a t e r i a l Examined: 2 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), VI.23.59 ( N . J . F i l m e r ) . ' EPHEMERELLA INERMIS EATON E p h e m e r e l l a i n a r m i s E a t o n , Needham, 1935, The B i o l o g y of M a y f l i e s , 604 ( B i b l i o g r a p h y ) A d u l t : A v e r y dark s p e c i e s ; . t h o r a c i c noturn p o l i s h e d deep b l a c k i s h brown; f o r e l e g d u l l g r e e n i s h g r e y ; femora l i g h t y e l l o w i s h amber i n a l l l e g s ; t a r s i d i r t y w h i t i s h ; wings h y a l i n e , a b l a c k i s h brown s p o t a t the extreme base of t h e f o r e w i n g ; v e n a t i o n p a l e , y e l l o w i s h t o h y a l i n e ; no s p i n e a t apex of f o r e t r o c h a n t e r ; abdominal t e r g i t e s dark r e d d i s h brown t o b l a c k i s h brown, the l a s t t h r e e y e l l o w i s h to r e d d i s h , l a t e r a l m argins l i g h t y e l l o w i s h , j o i n i n g s opaque; s t e r n i t e s p a l e r ; 2nd f o r c e p s j o i n t not s w o l l e n a p i c a l l y ; 3 r d f o r c e p s j o i n t s c a r c e l y l o n g e r t h a n wide; penes u n i t e d , somewhat s w o l l e n a p i c a l l y ; a p i c a l n o t c h between penes s h a l l o w ; l a t e r a l a p i c a l margins of.penes p r o j e c t i n g f o r w a r d as s h o r t , b l u n t , and i n w a r d l y d i r e c t e d p r o c e s s e s ; no a p i c a l s p i n e s on penes; but t h e r e a r e 4-5 l a t e r a l s p i n e s some d i s t a n c e from the apex on each s i d e ; t a i l s g r e y i s h w h i t e , j o i n i n g s opaque. Nymph: A dark r e d d i s h brown nymph; head and t h o r a x i r r e g u l a r l y m o t t l e d l i g h t and dark; l a t e r a l margins of pronotum p a l e ; l e g s b l a c k i s h brown, the femora, w i t h 3 l a r g e p a l e a r e a s , t i b i a e p a l e a t bases and a p i c e s , t a r s i p a l e a t a p i c e s ; l o n g s p i n e s a l o n g p o s t e r i o r m a rgins of the femora; and on the upper s u r f a c e s o f the f o r e femora a re l o n g s p i n e s a r r a n g e d i n an i r r e g u l a r t r a n s v e r s e a p i c a l band; no t e e t h or s p i n e s -187-• n the a n t e r i o r margins o f the f o r e femora; clau/s u/ith 8 t e e t h each; no d o r s a l abdominal s p i n e s ; w e l l d e v e l o p e d l a t e r a l e x t e n s i o n s o f abdominal t e r g i t e s p r e s e n t ; t e r g i t e s each w i t h a p a i r of s u b m e d i a l l a r g e p a l e s p o t s on p o s t e r i o r margin; on mi d d l e segments, e s p e c i a l l y 5 and 6, the median l i n e i s o f t e n p a l e and on t h e s e t e r g i t e s t h e r e a r e o f t e n l a r g e p a l e p a t c h e s j u s t above the g i l l s ; l a t e r a l e x t e n s i o n s marked by dark median t r a n s v e r s e bands; p o s t e r o - l a t e r a l s p i n e s on segments 6-8 s h o r t e r t h a n wide, on the o t h e r s , t h e w i d t h e q u a l s the l e n g t h ; s t e r n i t e s y e l l o w i s h - b r o w n , a p i c a l s t e r n i t e s and the l a t e r a l m argins of the m i d d l e ones b l a c k i s h brown; may be t r a c e s of dark submedian o b l i q u e dashes on the a n t e r i o r margins and of dark dots near the c e n t e r of the s t e r n i t e ; g i l l s on segments 3-7; no g i l l e l y t r o i d , the g i l l on segment 3 o v e r l a p s the f o l l o w i n g one l / 3 or l e s s of i t s l e n g t h ; . h e a v y p i g m e n t a t i o n on upper p o r t i o n o f g i l l on segment 3 i s i n 3 l o b e s , a l t h o u g h the s i d e l o b e s may be s m a l l ; lower p o r t i o n of g i l l on segment 3 i s c l e f t f o r l/2 i t s l e n g t h at most; g i l l on segment 7 i s minute; t a i l s y e l l o w i s h brown u s u a l l y w i t h many median and a p i c a l bands but may be unbanded, f r i n g e d w i t h l o n g h a i r s i n the a p i c a l p o r t i o n s , and never w i t h w h o r l s o f s p i n e s a t j o i n i n g s i n the b a s a l p o r t i o n s . E c o l o g y ; Nymphs of t h i s s p e c i e s have been c o l l e c t e d from the middle and edges of many l o c a t i o n s on the A l o u e t t e R i v e r , u s u a l l y from depth o f 1 to 2 f e e t , and o c c a s i o n a l l y deeper. The stream bed i n c l u d e d s i l t , mud, sand, g r a v e l , r o c k s , b o u l d e r s , and bedrock, and the c u r r e n t v a r i e d from q u i e t water t o r a p i d s . The nymphs were taken d u r i n g the e n t i r e y e a r . -188-D i s t r i b u t i o n : C o l o r a d o , Wyoming, Montana, Utah, Nevada, New M e x i c o , Oregon, B r i t i s h C o l u mbia. M a t e r i a l Examined: 3 Nymphs, B r i t i s h C o l u mbia: A l o u e t t e R i v e r (Haney), V.26.59 (N.3. F i l m e r ) , 4 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), XI.8.59, (N.3. F i l m e r ) , 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), IX.26.59 (N.3. F i l m e r ) . EPHEMERELLA INFREQUENS McDUNNOUGH  E p h e m e r e l l a i n f r e q u e n s McDunnough, Needham, 1935, The B i o l o g y o f M a y f l i e s , 605 ( B i b l i o g r a p h y ) A d u l t : A r e d d i s h brown m a y f l y ; eyes o f male l i g h t orange; head l i g h t brown; pronotum and a n t e r i o r l a t e r a l m argins o f mesonotum p u r p l i s h brown; r e s t o f mesonotum deep o l i v e brown, r e d d i s h brown p o s t e r i o r l y w i t h 2 s l i g h t l y r a i s e d b l a c k i s h l i n e s a n t e r i o r to t h e s c u t e l l u m ; l e g s l i g h t y e l l o w ; wings h y a l i n e , bases t i n g e d w i t h y e l l o w i s h brown; v e n a t i o n p a l e ; c r o s s v e i n s i n d i s t i n c t , e s p e c i a l l y i n b a s a l c o s t a l space; no s p i n e s on apex o f f o r e t r o c h a n t e r ; abdominal t e r g i t e s l i g h t r e d d i s h brown, the p o s t e r i o r margins smoky; p l e u r a l f o l d n a r r o w l y y e l l o w i s h ; s t e r n i t e s d u l l p u r p l i s h brown, a p i c a l s t e r n i t e s y e l l o w i s h brown, and middle s t e r n i t e s w i t h t r a c e s o f p a l e semi t r a n s p a r e n t a r e a s on a n t e r i o r m a r g i n s ; 2nd f o r c e p s j o i n t d i s t i n c t l y s w o l l e n a p i c a l l y ; 3 r d f o r c e p s j o i n t s c a r c e l y l o n g e r than wide; penes u n i t e d , somewhat s w o l l e n a p i c a l l y ; a p i c a l n o t c h between penes s h a l l o w ; l a t e r a l a p i c a l m a r gins of penes p r o j e c t i n g f o r w a r d as d i s t i n c t s h o r t , b l u n t , i n w a r d l y d i r e c t e d p r o c e s s e s ; penes each w i t h 2-4 a p i c a l s p i n e s , and 4-5 o t h e r s , i n 2 gr o u p s , f u r t h e r down; t a i l s y e l l o w i s h b a s a l l y , w h i t i s h a p i c a l l y , w i t h j o i n i n g s n a r r o w l y r i n g e d w i t h dark brown. -189-Nymph: A dark r e d d i s h t o b l a c k i s h brown s p e c i e s ; v e r t e x , l a t e r a l p o r t i o n s of pronotum, and a n t e r i o r p o r t i o n of mesonotum i n d i s t i n c t l y m o t t l e d w i t h dark brown: no d i s t i n c t p a l e markings on pronotum; l e g s r e d d i s h brown, femcra i r r e g u l a r l y b l o t c h e d w i t h y e l l o w i s h , t i b i a e and t a r s i p a l e banded b a s a i l y and a p i c a l l y ; no t e e t h or s p i n e s on a n t e r i o r margins o f f o r e femora; l o n g s p i n e s on p o s t e r i o r margins of a l l femora, and a l s o on upper s u r f a c e i n a t r a n s v e r s e a p i c a l band; claws w i t h 5-6 d e n t i c l e s ; no d o r s a l abdominal s p i n e s ; l a t e r a l e x t e n s i o n s of t e r g i t e s l e s s d e v e l o p e d than i n E. i n e r m i s ; no dark t r a n s v e r s e band on t h e s e l a t e r a l e x t e n s i o n s ; abdominal t e r g i t e s u s u a l l y w i t h a p a l e m i d - d o r s a l l i n e ; no p a l e s p o t s on p o s t e r i o r margins of t e r g i t e s or p a l e l a t e r a l a r e a s above g i l l s ; s t e r n i t e s unmarked; g i l l s on segments 3-7; no e l y t r o i d g i l l s ; g i l l on segment 3 o v e r l a p s the f o l l o w i n g one l / 3 or l e s s of i t s l e n g t h ; p i g m e n t a t i o n on upper p o r t i o n of g i l l on segment 3 i s none or s l i g h t ; upper p o r t i o n of g i l l on segment 3 w i t h a l o b e d base, t h i s p o r t i o n i s l o n g e r than the l o w e r p o r t i o n by l / 4 ; g i l l on segment 7 i s l e s s than l / 3 the l e n g t h of the g i l l on segment 3; t a i l s r e d d i s h brown, w i t h s e v e r a l y e l l o w i s h bands, f r i n g e d w i t h l o n g h a i r s i n a p i c a l p o r t i o n ; and never w i t h w h o r l s o f s p i n e s a t the j o i n i n g s of the b a s a l p o r t i o n . D i s t r i b u t i o n : C a l i f o r n i a , Utah, Montana, Wyoming, A l b e r t a , B r i t i s h C o l u m bia. No specimens o f t h i s s p e c i e s were examined. EPHEMERELLA 3AC0BI McDUNNOUGH E p h e m e r e l l a j a c o b i McDunnough, A l l e n and t-dmunds, 1961, Ann. Ent. Soc. Amer. 54:603-612 ( B i b l i o g r a p h y ) -190-A d u l t : T h i s s p e c i e s i s a member o f the subgenus C a u d a t e l l a ; t h o r a x deep brown; eyes b l a c k i s h w i t h a r e d d i s h t i n g e ; no s p i n e on apex of f o r e t r o c h a n t e r ; wings narrow, h y a l i n e ; l o n g i t u d i n a l v e i n s i n c o s t a l h a l f p a l e b r o w n i s h ; c r o s s v e i n s p a l e and i n c o n s p i c u o u s ; abdominal t e r g i t e s b l a c k i s h , p o s t e r i o r margins b r o w n i s h , p r o d u c i n g a r i n g e d appearance; s t e r n i t e s u n i f o r m l y dark brown; l a t e r a l margins of s t e r n i t e s 8 and 9 p a l e ; penes s h o r t and br o a d ; a p i c a l n o t c h between penes deep; l a t e r a l a p i c a l margins of penes p r o j e c t f o r w a r d as s h o r t , b l u n t , i n w a r d l y d i r e c t e d p r o c e s s e s ; u s u a l l y s p i n e s on penes; 3 r d f o r c e p s j o i n t s c a r c e l y l o n g e r than wide; t a i l s o f f e m a l e b l a c k i s h a t base, p a l i n g a p i c a l l y , and d i s t i n c t l y dark r i n g e d . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h C olumbia No specimens of t h i s s p e c i e s were examined. EPHEMERELLA LODI MAYO Ep h e m e r e l l a l o d i Mayo, A l l e n and Edmunds, 1963, Can. Ent. 95:621 ( B i b l i o g r a p h y ) A d u l t : (Male) T h i s s p e c i e s has been p l a c e d i n the subgenus E u r y l o p h e l l a ; pronotum y e l l o w i s h brown t i n g e d w i t h r e d ; r e s t of t h o r a x r e d d i s h brown; wings s l i g h t l y a m b e r - t i n g e d ; v e n a t i o n y e l l o w , c r o s s v e i n s p a l e ; s t i g m a t i c c r o s s v e i n s anastomosed; wings o f female w i t h r e d d i s h c o l o u r i n g a t the bases of the 5c and R; abdomen l i g h t e r t h a n " t h e t h o r a x ; t e r g i t e s 1-3 are r e d d i s h brown, w i t h wide brown bands on the p o s t e r i o r m a r g i n s ; t e r g i t e s 4-10 y e l l o w i s h w i t h r e d d i s h brown p o s t e r i o r m a r g i n s ; t e r g i t e s 8 and 9 w i t h a r e d d i s h s t r e a k near the p l e u r a l f o l d ; l a t e r a l l y each -191-t e r g i t e i s marked w i t h a b l a c k o b l i q u e s t r e a k near the p l e u r a l f o l d , and w i t h b l a c k i s h s p o t s or s t r e a k s on each s i d e of the m i d l i n e ; the female i s l i g h t e r , the d o r s a l m arkings b e i n g a m o t t l e d r e d , and a wide m o t t l e d m i d d o r s a l s t r e a k ; t a i l s y e l l o w , the j o i n i n g s a dark r e d d i s h brown; 2nd f o r c e p s j o i n t not s t r o n g l y bowed o r c o n s t r i c t e d ; 3 r d f o r c e p s j o i n t a t l e a s t t w i c e as l o n g as wide. Nymph: A dark brown nymph, o f t e n w i t h a p a l e median s t r i p e on the head, t h o r a x , and abdomen, and w i t h s c a t t e r e d p a l e s p o t s and maculae; female w i t h p a i r e d o c c i p i t a l t u b e r c l e s , male w i t h o u t ; c l a w s w i t h 7-10 d e n t i c l e s ; d o r s a l abdominal s p i n e s on t e r g i t e s 1-10, d e c r e a s i n g i n s i z e p o s t e r i o r l y ; m o d e r a t e l y l o n g on t e r g i t e s 1-8, s h o r t and b l u n t on 9, b a r e l y d i s c e r n a b l e on 10, w i d e s t a p a r t on segments 2-4; p o s t e r o -l a t e r a l s p i n e s w e l l d e v e l o p e d on segments 2 and 3; t e r g i t e s r i c h brown w i t h 3-4 p a l e d o t s between t u b e r c l e s ; t e r g i t e s 2-4 o f t e n w i t h wide p a l e s u b l a t e r a l s t r i p e s and 9-10 w i t h narrow p a l e submedian s t r i p e s ; t a i l s a l t e r n a t e l y banded w i t h narrow l i g h t brown and wide dark brown bands; g i l l s on segments 4-7; r u d i m e n t a r y g i l l on segment 1; g i l l on segment 4 s e m i - o p e r c u l a t e . E c o l o g y ; T h i s s p e c i e s has been taken from the edges of two l o c a t i o n s on the A l o u e t t e R i v e r , a t depths of 1 to 2 f e e t . The s t r e a m bed c o n s i s t e d of s i l t , mud, and r o c k s . The c u r r e n t was s t i l l and q u i e t . They were tak e n i n 3une. In one c a s e , however, one nymph was t a k e n i n November from the m i d d l e o f t h e r i v e r , from a s u b s t r a t e of r o c k s , g r a v e l , and b o u l d e r s , i n a r i p p l i n g c u r r e n t . D i s t r i b u t i o n : B r i t i s h C olumbia. -192-M a t e r i a l Examined; 2 Nymphs,. B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), VI.9.59 ( N . J . F i l m e r ) EPHEIY1ERELLA SPINIFERA NEEDHAM Ep h e m e r e l l a s p i n i f e r a Needham, A l l e n and Edmunds, 1963, M i s c . Pub. E n t . Soc. Amer. 3 (5) : 176 ( B i b l i o g r a p h y ) A d u l t : T h i s s p e c i e s i s a member of the subgenus P r u n e l l a ; no s p i n e a t apex of f o r e t r o c h a n t e r ; wings h y a l i n e ; v e n a t i o n dark brown; abdominal t e r g i t e s 2-6 b l a c k o r deep p u r p l i s h brown w i t h p a l e r m a r g i n s ; s t e r n i t e s w i t h dark m a r k i n g s ; 2nd f o r c e p s j o i n t not bowed or c o n s t r i c t e d , c o n s i d -e r a b l y w i d e r a t base t h a n a t apex; 3 r d f o r c e p s j o i n t a t l e a s t t w i c e as l o n g as wide; s u b g e n i t a l p l a t e between the f o r c e p s bases produced and w i t h a broad V-shaped e m a r g i n a t i o n ; penes w i t h a U-shaped a p i c a l median c l e f t ; l o b e s of penes expanded a p i c a l l y ; t a i l s b l a c k . Nymph: No f r o n t a l horns or f r o n t a l s h e l f ; p rominent o c c i p i t a l t u b e r c l e s ; pronotum w i t h w e l l - d e v e l o p e d , s h a r p - p o i n t e d s u b m a r g i n a l s p i n e s , and 2 p a i r s of s l e n d e r , s h a r p p o i n t e d s u b m e d i a l s p i n e s , the i n t e r i o r s p i n e i n each p a i r b e i n g t w i c e as h i g h as the p o s t e r i o r one, mesonotum w i t h a p a i r of submedian t u b e r c l e s on the a n t e r i o r m a r g i n , two p a i r s of submedian s p i n e s , the p o s t e r i o r p a i r b e i n g the l a r g e r , and a median t u b e r c l e on the p o s t e r i o r m a r g i n ; prosternum w i t h a median t u b e r c l e ; no t e e t h o r s p i n e s on f o r e femora w i t h o n l y s c a t t e r e d h a i r s , not a r r a n g e d i n a m a r g i n a l row; t i b i a l "thumb" s l e n d e r , sharp p o i n t e d , not r e a c h i n g to m i d d l e of t a r s u s ; d o r s a l abdominal s p i n e s p r o m i n e n t , tho s e on segments 2-7 s u b e q u a l , t h o s e on 8 and 9 f o u r t i m e s as l o n g as the p r e c e d i n g ones; s p i n e s on segment 8 may be s t r o n g l y bent -193-backward o r downward; t e r g i t e s p a l e b r o w n i s h to r e d d i s h brown, s t e r n i t e s y e l l o w i s h , w i t h i n d i s t i n c t d a r k e r dashes on each s i d e ; g i l l s on abdominal segments 3-7; no g i l l e l y t r o i d , g i l l on segment 3 o v e r l a p s the f o l l o w i n g one by l / 3 or l e s s of i t s l e n g t h ; upper p o r t i o n of g i l l on segment 3 2/3 or more l o n g e r than the l o w e r p o r t i o n , p i g m e n t a t i o n i n t h i s p o r t i o n i s heavy and g e n e r a l , showing no l o b i n g ; l o w e r p o r t i o n of g i l l on segment 3 of o n l y 2 l a y e r s , t h e secondary l o b e s not c l o s e t o g e t h e r ; g i l l on segment 7 m i n u t e ; t a i l s y e l l o w i s h , banded, w h o r l s o f s p i n e s a t j o i n i n g s . E c o l o g y : Nymphs o f t h i s s p e c i e s were t a k e n from the m i d d l e of 3 l o c a t i o n s on the A l o u e t t e R i v e r , a t depths of 1 t o 5 f e e t . The st r e a m bed c o n s i s t e d o f sand, g r a v e l , r o c k s , and b o u l d e r s , and the c u r r e n t v a r i e d from q u i e t r i p p l e s t o r a p i d s . They were a l s o found from the edge o f one of t h e s e l o c a t i o n s , i n q u i e t w a t e r . They were c o l l e c t e d i n Dune and November. D i s t r i b u t i o n ; Montana, Utah, B r i t i s h C o l u mbia. M a t e r i a l Examined: 2 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney) VI.23.59 (N.3. F i l m e r ) EPHEMERELLA TERESA TRAVER E p h e m e r e l l a t e r e s a T r a v e r , A l l e n and Edmunds, 1963, Ann. E n t . Soc. Amer. 56 (5) : 583-600 A d u l t : T h i s s p e c i e s b e l o n g s to the subgenus S e r r a t e l l a ; head brown; t h o r a x c h o c o l a t e brown; l e g s l i g h t brown; wings h y a l i n e ; l o n g i t u d i n a l v e i n s l i g h t brown, o t h e r s p a l e ; no s p i n e on apex of f o r e t r o c h a n t e r ; abdominal t e r g i t e s brown, p o s t e r i o r margins d a r k e r ; s t e r n i t e s l i g h t brown; 3rd f o r c e p s j o i n t s c a r c e l y l o n g e r than wide; penes not c o n s t r i c t e d -194-near the base, the s i d e s n e a r l y p a r a l l e l , and the i n n e r margin of each p e n i s l o b e i s w i t h o u t a s u b a p i c a l n o t c h ; p e n i s l o b e s w i t h o u t l a t e r a l s u b a p i c a l p r o j e c t i o n s ; t a i l s p a l e , r i n g e d w i t h dark brown a t j o i n i n g s . Nymph: Head and t h o r a x smooth; m a x i l l a r y p a l p i v e r y s m a l l , a p p a r e n t l y w a n t i n g ; median l i n e o f pronotum e l e v a t e d a n t e r i o r l y , d e p r e s s e d p o s t e r i o r l y , w i t h c a r i n a e on l a t e r a l s m a r g i n ; no t e e t h on a n t e r i o r margins of f o r e femora, and no s p i n e s ; l e g s p a l e brown, a p i c e s of j o i n t s r e d d i s h brown; c l a w s w i t h 9-10 d e n t i c l e s ; wing pads w i t h a c o s t a l margin p u r p l i s h ; d o r s a l abdominal s p i n e s on segments 4-7 o n l y , s h o r t and f a r a p a r t on 4, l o n g e r and c l o s e r t o g e t h e r on the r e s t ; l a t e r a l e x t e n s i o n and p o s t e r o - l a t e r a l s p i n e s on abdominal t e r g i t e s m o d e r a t e l y d e v e l o p e d ; t e r g i t e s p a l e r e d d i s h brown w i t h d a r k e r l a t e r a l p a t c h e s on t e r g i t e s 4-8 and dark d o t s on t e r g i t e 9; s t e r n i t e s y e l l o w i s h w i t h a row o f dark l a t e r a l dashes; g a n g l i o n i c a r e a s o f t e n darkened; g i l l s on segments 3-7; t a i l s p a l e y e l l o w i s h , each j o i n i n g w i t h a w h o r l o f dark r e d d i s h brown s p i n e s , may be dark i n d i s t a l h a l f . E c o l o g y : These nymphs were c o l l e c t e d from the m i d d l e o f s e v e r a l l o c a t i o n s of the A l o u e t t e R i v e r , from a depth o f 1 to 2 f e e t . The s u b s t r a t e c o n s i s t e d of g r a v e l , r o c k s , b o u l d e r s , and bedrock. In a l l c a s e s the c u r r e n t was r a p i d . A l l specimens were ta k e n d u r i n g 3une and Du l y . D i s t r i b u t i o n : C a l i f o r n i a , B r i t i s h Columbia M a t e r i a l Examined: 1 Nymph, B r i t i s h C olumbia: A l o u e t t e R i v e r (Haney), VI.2.59 (N.3. F i l m e r ) , 2 Nymphs, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), VI.23.59 (N.3. F i l m e r ) . -195-EPHEfflERELLA TIBIALIS fflcDUNNOUGH E p h e m e r e l l a t i b i a l i s fflcDunnough, A l l e n and Edmunds, 1963, Ann. E n t . Soc. Amer. 56 (5) : 583-600 A d u l t ? T h i s s p e c i e s has been p l a c e d i n the subgenus S e r r a t e l l a ; males deep p u r p l i s h brown; t h o r a x b l a c k i s h d o r s a l l y ; l e g s y e l l o w i s h ; f o r e t i b i a e deep smoky, m i d d l e and h i n d t i b i a e w i t h r e d d i s h a p i c a l bands; f o r e t i b i a e t w i c e as l o n g as the femora; no s p i n e s at apex of f o r e t r o c h a n t e r ; wings v i t r e o u s ; v e n a t i o n p a l e grey-brown; c r o s s v e i n s d i s t i n c t ; abdominal t e r g i t e s 3-8 w i t h narrow w h i t i s h t r a n s l u c e n t a n t e r i o r m a r g i n s ; s t e r n i t e s w i t h s l i g h t l y darkened g a n g l i o n i c a r e a s ; 3 r d f o r c e p s j o i n t s c a r c e l y l o n g e r than wide; penes b l a c k i s h ; u n i t e d , s w o l l e n a p i c a l l y ; penes c o n s t r i c t e d near base, i n n e r margin of each l o b e w i t h a s u b a p i c a l n o t c h ; p e n i s l o b e s rounded on l a t e r a l a p i c a l m a r g i n s , w i t h o u t a s u b a p i c a l p r o j e c t i o n ; u s u a l l y w i t h b a r b - l i k e d o r s o - l a t e r a l s p i n e s , one on each s i d e of each p e n i s ; middle t a i l n o t n o t i c e a b l y l o n g e r t h a n the o u t e r ones; t a i l s smoky, d a r k e r a t j o i n i n g s . Nymph; Head and t h o r a x smooth, w i t h o u t h a i r s or t u b e r c l e s ; m a x i l l a r y p a l p i m o d e r a t e l y l o n g ; t h o r a x and abdomen s l e n d e r and b l a c k i s h , sometimes w i t h a narrow m i d - d o r s a l p a l e l i n e ; l e g s s h o r t ; no t e e t h o r s p i n e s o n a n t e r i o r margins of f o r e femora; no c o n s p i c u o u s h a i r s on l e g s ; l e g s p u r p l i s h brown, r e d , or f u s c i o u s w i t h a s m a l l p a l e spot b a s a l l y and a p a l e a p i c a l band and i n c o m p l e t e s u b a p i c a l mark on each femur; t i b i a e and t a r s i each w i t h b a s a l and a p i c a l p a l e bands; c l a w s w i t h 5-7 d e n t i c l e s ; d o r s a l abdominal s p i n e s on segments 2-9, narrow and a c u t e ; p o s t e r i o r margins of t e r g i t e s s t r a i g h t ; t u b e r c l e s may be -196-s w o l l e n on segments 2 and 8; l a t e r a l e x t e n s i o n s o f abdominal t e r g i t e s not prominent; p o s t e r o - l a t e r a l s p i n e on segment 9 not e x t e n d i n g beyond the margin o f segment 10; s t e r n i t e s unmarked; g i l l s on segments 3-7; t a i l s a p p r o x i m a t e l y equal i n l e n g t h , a l t e r n a t e l y banded brown and p a l e ; w h o r l s of s p i n e s a t each j o i n i n g . E c o l o g y : Nymphs of t h i s s p e c i e s mere t a k e n from many l o c a t i o n s on the A l o u e t t e R i v e r , u s u a l l y a t depths o f from 1 t o 2 f e e t . The stream bed v a r i e d from mud, t h r o u g h sand, g r a v e l and r o c k s , to b o u l d e r s . The c u r r e n t was u s u a l l y r i p p l i n g , but o c c a s i o n a l l y was q u i e t or r a p i d . They were c o l l e c t e d d u r i n g the whole y e a r , e x c e p t d u r i n g the w i n t e r months of October t o J a n u a r y . D i s t r i b u t i o n ; Wyoming, C a l i f o r n i a , B r i t i s h C o l u mbia. M a t e r i a l Examined; 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney), VI.16.59, ( N . J . F i l m e r ) ; 1 Nymph, B r i t i s h C o l u m b i a : A l o u e t t e R i v e r (Haney) V I I I . 2 6 . 5 9 ( N . J . F i l m e r ) . E p h e m e r e l l a sp. 1 A d u l t : T h i s a d u l t c l o s e l y resembles E . t e r e s a , the o n l y d i f f e r e n c e b e i n g the l a c k o f a dark margin on each abdominal t e r g i t e . F u r t h e r i n v e s t i g a t i o n may p l a c e t h i s specimen i n t h a t s p e c i e s . Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: 1 Male, B r i t i s h C o l u m b i a : Q u e s n e l , VI.31.48 (H.R. McCarthy) -197-SUBFAIYIILY LEPTOHYPHIIMAE Genus T r i c o r y t h o d e s Ulmer T r i c o r y t h o d e s , IMeedharn, 1935, The B i o l o g y of M a y f l i e s , 630 ( b i b l i o g r a p h y ) A d u l t : S m a l l t o moderate s i z e d m a y f l i e s , u s u a l l y b l a c k i s h or dark brown, fe m a l e s p a l e r ; eyes w i d e l y s e p a r a t e d ; f o r e l e g o f male s l e n d e r , almost o r as l o n g as the body;- f o r e femur 2/5 as l o n g as the t i b i a , which i s 1-1/2 t i m e s as l o n g as the t a r s u s ; t a r s i 5 - j o i n t e d , 2nd j o i n t may be as l o n g as femur; m i d d l e and h i n d femora l o n g e r than t i b i a e , and 2-1/2 t i m e s as l o n g as t a r s i ; t e r m i n a l t a r s a l j o i n t the l o n g e s t ; c l a w s of m a l e f o r e t a r s u s s i m i l a r , b l u n t , a l l o t h e r s d i s s i m i l a r ; p o s t e r i o r branch of IYI of f o r e w i n g and the l o n g i n t e r c a l a r y between the branches o f the IYI, s h o r t e r than the a n t e r i o r b r a n c h , not e x t e n d i n g t o the base; c r o s s v e i n s numerous; Sc and R u s u a l l y p u r p l i s h b l a c k e x c e p t a t apex; f o r c e p s 3 r j o i n t e d , 2nd j o i n t w i t h an o v o i d s w e l l i n g a t base of i n n e r m a r g i n , r e s t l o n g , s l e n d e r , and t a p e r i n g , 3 r d j o i n t s h o r t , o v o i d ; f o r c e p s base e n t i r e , a p i c a l margin d e e p l y e x c a v a t e d m e d i a l l y ; penes .united f o r 3/4 of t h e i r l e n g t h , f o r m i n g a c o n i c a l s t r u c t u r e ; d i s t a l p o r t i o n s s e p a r a t e d by a rounded or U-shaped n o t c h ; p o s t e r i o r m argin of s u b a n a l p l a t e of femal e e n t i r e o r s l i g h t l y o b t u s e ; t a i l s t h r e e . Mymph: A p i c a l margin of labrum d e e p l y notched m e d i a l l y ; i n n e r c a n i n e s of m a n d i b l e s as l o n g as o u t e r ones; m a x i l l a r y p a l p i r e d u c e d : l a b i a l p a l p i 3 - j o i n t e d , s m a l l ; c laws not p e c t i n a t e ; no g i l l rudiment on abd o m i n a l segment 1; g i l l s on segments 2-6 d o u b l e , a r g i n s of each -198-p l a t e e n t i r e , not f r i n g e d ; upper p l a t e o f g i l l on segment 2 l a r g e , e l y t r o i d , t r i a n g u l a r , lower p l a t e b i f i d , s m a l l e r , c o n s i s t i n g o f a l o n g s l e n d e r p o r t i o n and an o v o i d one; t a i l s t h r e e , w i t h a w h o r l o f s p i n e s a t each j o i n i n g . Genotype; T r i c o r y t h o d e s e x p l i c a t u s ( i n T r i c o r y t h u s ) Eaton TRICORYTHODES (YIINUTU5 TRAVER T r i c o r y t h o d e s minutus T r a v e r , Needham, 1935, The B i o l o g y of fflayfli.es, 636 ( B i b l i o g r a p h y ) A d u l t ; ) A s m a l l r e d d i s h brown m a y f l y ; head o f male b r i g h t r e d d i s h w i t h a b l a c k i s h p o s t e r i o r margin; t h o r a x red-brown, pronotum shaded w i t h b l a c k m e d i a l l y and l a t e r a l l y , mesonotum deeper i n c o l o u r ; l e g s l i g h t r e d d i s h - b r o w n , e x c e p t f o r e t i b i a e . a n d t a r s i which a re w h i t i s h , wings h y a l i n e , w h i t i s h ; v e n a t i o n , e x c e p t f o r the p u r p l i s h Sc and R, p a l e ; abdomen r e d d i s h brown; t e r g i t e s 1, 2, 8, and 9 l a r g e l y b l a c k i s h ; m i d d l e t e r g i t e s w i t h a red-brown median l i n e . o n each s i d e o f which i s heavy b l a c k i s h s h a d i n g , b e a r i n g a p a i r o f l a r g e b l a c k l a t e r a l t r i a n g l e s on s t e r n i t e 9; f o r c e p s base s h a l l o w l y e x c a v a t e d . Nymph; Unknown D i s t r i b u t i o n ; B r i t i s h C o l u m b i a , Utah ' No specimens o f t h i s s p e c i e s were examined. T r i c o r y t h o d e s sp. 1  A d u l t : Unknown Nymph: Abdominal t e r g i t e s w i t h b l a c k m arkings and a p a l e narrow median l i n e ; o p e r c u l a t e g i l l s b o r d e r e d w i t h b l a c k on the m e d i a l and p o s t e r i o r edges. -199-D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: 60 Nymphs, B r i t i s h C o l u m b i a , N i c o l a Creek (G.G.E. S c u d d e r ) SUPERFAMILY CAENOIDEA  FAMILY CAENIDAE  SUBFAMILY CAENINAE A d u l t : S m a l l m a y f l i e s ; eyes of male s i m p l e , not grooved or d i v i d e d , f a r a p a r t ; l a t e r a l o c e l l i u s u a l l y l a r g e and p r o m i n e n t ; t a r s i 4-j o i n t e d , e x c e p t f o r an a d d i t i o n a l s h o r t b a s a l j o i n t on f o r e t a r s u s of the male; f o r e i u i n g w e l l d e v e l o p e d , e s p e c i a l l y i n the c u b i t o - a n a l r e g i o n ; wings o f t e n semi-opaque; u s u a l l y C and Sc t i n g e d w i t h p u r p l i s h e x c e p t a t the t i p ; o u t e r and p o s t e r i o r margins s e t a c e o u s ; Of of Rs v e r y deep; no m a r g i n a l i n t e r c a l a r i e s ; 2 l o n g c u b i t a l i n t e r -c a l a r i e s ; c r o s s v e i n s few; h i n d wing a b s e n t ; t a i l s t h r e e ; f o r c e p s base e n t i r e , e x c a v a t e d on a p i c a l m a r g i n , or w i t h a median and two l a t e r a l p r o j e c t i o n s on i t s a p i c a l m a r g i n . Nymph: Nymphs s p r a w l i n g , t a p e r e d p o s t e r i o r l y , d e n s e l y c o v e r e d w i t h f i n e h a i r s ; a l l c laws s i m i l a r ; l a t e r a l m argins of abdominal t e r g i t e s 2-9 produced i n t o f l a t e x t e n s i o n s b e a r i n g p o s t e r o - l a t e r a l s p i n e s ; g i l l s on segments 1-6; g i l l s on segment 1 r u d i m e n t a r y f i l a m e n t s ; g i l l s on segment 2 e l y t r o i d , a l m o s t c o m p l e t e l y c o v e r i n g a l l of the r e m a i n d e r ; t a i l s t h r e e , f r i n g e d e v e n l y on both s i d e s . GENUS CAENIS STEPHENS C a e n i s , Needham, 1935, The B i o l o g y of M a y f l i e s , -643 ( B i b l i o g r a p h y ) A d u l t : -Second j o i n t of antenna not more th a n t w i c e as l o n g as the b a s a l -200-j o i n t ; pronotum dee p l y e x c a v a t e d p o s t e r i o r l y i n the median a r e a ; p r e s t e r n u m two or t h r e e t i m e s l o n g e r than b r o a d , so t h a t the f o r e coxae are c l o s e t o g e t h e r ; f o r e l e g of male as l o n g as the body, c l a w s as i n T r i c o r y t h o d e s ; p o s t e r i o r branch of IT! and the l o n g i n t e r -c a l a r y between the branches of the ffl as l o n g as t h e a n t e r i o r b r a n c h , e x t e n d i n g to the base o f the wing; c r o s s v e i n s a r r a n g e d s i n g l y , . u s u a l l y no i n t e r c a l a r y space w i t h more than 1 c r o s s v e i n ; 2 or 3 c r o s s v e i n s o n l y i n r a d i a l r e g i o n ; t a i l s t h r e e , o f t e n 3 t i m e s t h e l e n g t h of the body i n the male, the m i d d l e t a i l may be s l i g h t l y l o n g e r ; abdomen u s u a l l y p a l e y e l l o w i s h w h i t e , t e r g i t e s o f t e n s u f f u s e d w i t h b l a c k i s h ; f o r c e p s base e n t i r e , a p i c a l margin s l i g h t l y convex; f o r c e p s 1 - j o i n t e d , s h a r p - p o i n t e d ; p o s t e r i o r margin of s u b a n a l p l a t e o f - f e m a l e e n t i r e ; penes u n i t e d , broad and p l a t e - l i k e . Nymph: Head and pronotum narrower t h a n the mesonotum, no t u b e r c l e s on the head; a p i c a l margin of labrum s l i g h t l y concave; m a n d i b u l a r c a n i n e s as i n - T r i c o r y t h o d e s ; m a x i l l a r y p a l p i 3 - j o i n t e d , t w i c e as l o n g as the g a l e a - l a c i n i a ; g l o s s a e and p a r a g l o s s a e not f u s e d as i n T r i c o r y t h o d e s ; l a b i a l p a l p i 3 - j o i n t e d ; c l a w s s l e n d e r , c u r v e d a p i c a l l y , not p e c t i n a t e ; g i l l s on abdominal segments 1-6; g i l l s on segment 1 w e l l d e v e l o p e d f i l a m e n t o u s r u d i m e n t s ; g i l l s on segment 2 o p e r c u l a t e , l a r g e , and q u a d r a t e , t h e i r o u t e r margins rounded; g i l l s on segments 3-6 f r i n g e d on o u t e r 2/3 of t h e i r e n t i r e m a r g i n s ; a l l g i l l s s i n g l e ; p o s t e r o - l a t e r a l s p i n e s on t e r g i t e s more prominent than i n T r i c o r y t h o d e s not u p c u r v e d ; t a i l s t h r e e , a w h o r l o f s p i n e s on each j o i n i n g . Genotype: C a e n i s macrura Stephens -201 CAENIS  Key To Nymphs 1. Legs and t a i l s banded 2. Legs p a l e l y banded. T a i l s unbanded sp. 2 2. A n t e r i o r c o r n e r s of pronotum rounded sp. 1 A n t e r i o r c o r n e r s of pronotum sharp 3. 3. ITIesonotal wing pads w i t h dark l a t e r a l m a r g i n s , each b e a r i n g t h r e e dark l o b e s . No p a t t e r n on mesothorax sp. 3 ITiesonotal wing pads u n i c o l o u r e d . ITiesothorax w i t h a f a i n t V-shaped mark, open a n t e r i o r l y . . sp. 4 C a e n i s sp. 1  A d u l t : Unknown Nymph: A n t e r i o r c o r n e r s o f the pronotum rounded; p a l e s p o t s a t bases of wing pads; l e g s banded a l t e r n a t e l y l i g h t and dark; t a i l s a l t e r n a t e l y banded l i g h t and d a r k . D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: The a u t h o r has examined many nymphs of t h i s s p e c i e s , t a k e n by Dr. G.G.E. Scudder from VI.17.61 t o V.26.63, from the f o l l o w i n g l o c a t i o n s : B r i t i s h C o l u m b i a : B o r t a n o Lake, Canim Lake, S p r i n g h o u s e Lake, White Lake, F e l f e e r L a k e , Green Lake, W i l l i a m s Lake. C a e n i s sp. 2 A d u l t : Unknown N.yrnph: A s m a l l e r p a l e nymph; a n t e r i o r p r o n o t a l c o r n e r s s h a r p ; pronotum w i t h 2 p a l e s p o t s ; mesonotum w i t h 2 m e d i a l and 2 l a t e r a l p a l e s p o t s , i n the form o f a diamond, or u n i c o l o u r o u s ; l e g s a l t e r n a t e l y banded -202-u j i t h p a l e and l i g h t brown; t a i l s unbanded. D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: 11 Nymphs, B r i t i s h C o l u m b i a : B o i t a n o Lake, V.19.62 (G.G.E. S c u d d e r ) ; 13 Nymphs, B r i t i s h C o l u m b i a : S p r i n g h o u s e Lake, VI.2.62 (G.G.E. S c u d d e r ) ; 1 Nymph, B r i t i s h C o l u mbia: Rock Lake, IX.21.63 (G.G.E. S c u d d e r ) , 1 Nymph, B r i t i s h C o l u m b i a : W i l l i a m s Lake, VI,24.61 (G.G.E. S c u d d e r ) . C a e n i s s p. 3. A d u l t : Unknown Nymph: A n t e r i o r p r o n o t a l c o r n e r s s h a r p ; no p a t t e r n on mesonotum; mes o n o t a l wing pads w i t h dark l a t e r a l m a r g i n s , the i n n e r edges of t h e s e dark margins w i t h 3 p a l e i n d e n t a t i o n s each; l e g s a l t e r n a t e l y banded l i g h t and d a r k ; t a i l s a l t e r n a t e l y banded l i g h t and d a r k , the dark bands may be p a l e r . D i s t r i b u t i o n : B r i t i s h C o l umbia M a t e r i a l Examined: 4 Nymphs, B r i t i s h C o l u m b i a : S p r i n g h o u s e Lake, VI.18.61 (G.G.E. Scud d e r ) 3 Nymphs, B r i t i s h C o l u m b i a : B o i t a n o Lake, VI.17.61 (G.G.E. Scud d e r ) 2 Nymphs, B r i t i s h C o l u m b i a : F e l k e r Lake, VI.25.61 (G.G.E. Scudder) 1 Nymph, B r i t i s h C o l u m b i a : P a v i l i o n , VI.30.61 (G.G.E. Scudder) 21 Nymphs, B r i t i s h C o l u m b i a : Green Lake, VI.26.61 (G.G.E. Scudder) 1 Nymph, B r i t i s h C o l u m b i a : W i l l i a m s Lake, VI.24.61 (G.G.E. Scud d e r ) C a e n i s sp. 4 A d u l t : Unknown -203-Nymph: A n t e r i o r p r o n o t a l c o r n e r s s h a r p ; mesonotum w i t h a f a i n t U-shaped mark, the apex d i r e c t e d p o s t e r i o r l y ; no m a r k i n g s on the m e s o n o t a l wing pads; l e g s and t a i l s a l t e r n a t e l y banded l i g h t and d a r k . D i s t r i b u t i o n ; B r i t i s h Columbia M a t e r i a l Examined: 1 Nymph, B r i t i s h C o l u m b i a : Ulestujick, U.27.63 (G.G.E. Scud d e r ) 6 Nymphs, B r i t i s h C o l u m b i a : F e l k e r Lake, VI.25.61 (G.G.E. Scud d e r ) 5 Nymphs, B r i t i s h C o l u m b i a : Brunson Lake, VI.25.61 (G.G.E. Scudder) 1 Nymph, B r i t i s h C o l u m b i a : S p r i n g h o u s e Lake, VI;18.61 (G.G.E. Scudder) 2 Nymphs, B r i t i s h C o l u mbia: W i l l i a m s Lake, VI.24.61 (G.G.E. Scudder) SUPERFAMILY EPHEMEROIDEA  FAMILY EPHEMERIDAE  SUBFAMILY EPHEMERINAE A d u l t : U s u a l l y l a r g e m a y f l i e s ; eyes of male moderate to l a r g e , a p p r o x i -mated a p i c a l l y ; l e g s r a t h e r weak; t a r s i 4 - j o i n t e d , e x c e p t the f o r e t a r s u s of the male, which i s 5 - j o i n t e d ; c l a w s d i s s i m i l a r , e x c e p t the c l a w s on the male f o r e t a r s i ; which' are d i s s i m i l a r and b l u n t ; wings h y a l i n e ; v e i n s M and C u l s t r o n g l y d i v e r g e n t a t b a s e s ; M2 s t r o n g l y bent toward the Cu b a s a i l y ; s t i g m a t i c a r e a o f t e n narrowed; no sag i n the c o s t a l m a r g i n ; c r o s s v e i n s numerous; c o s t a l c r o s s v e i n s w e l l d e v e l o p e d ; m a r g i n a l i n t e r c a l a r i e s i r r e g u l a r ; c u b i t a l i n t e r c a l a r i e s resemble m a r g i n a l v e i n l e t s , c o n s i s t i n g of 2 to 4 f o r k s d e c u r v e n t from the a n t e r i o r branch of the c u b i t u s ; c o s t a l p r o j e c t i o n o f the h i n d wing low; Of of h i n d wing a b s e n t ; f o r c e p s 4 - j o i n t e d . Nymph: These a r e f o s s o r i a l , b u r r o w i n g nymphs; head w i t h a c o n s p i c u o u s -204-f r o n t a l p r o c e s s between the bases of the antennae; m a n d i b l e s w i t h e x t e r n a l t u s k s p r o j e c t i n g f o r w a r d and v i s i b l e d o r s a l l y ; t u s k s c u r v e upwards a p i c a l l y when viewed l a t e r a l l y , and d i v e r g e n t a t t i p s when viewed d o r s a l l y ; upper s u r f a c e s of t u s k s bear h a i r s o r s p i n e s , but not any t u b e r c l e s ; f o r e t i b i a e f o s s o r ' i a l ; g i l l s d o r s a l , c u r v i n g up over t h e abdomen, and w i t h f r i n g e d m a r g i n s . SUBFAMILY EPHEMERINAE  Key To A d u l t s 1. C r o s s v e i n s somewhat crowded at and below b u l l a . Wings w i t h a v a r i a b l e p a t t e r n o f dark s p o t s Ephemera L i n n a e u s . C r o s s v e i n s not crowded a t b u l l a . Wings w i t h no d i s t i n c t p a t t e r n o f dark s p o t s , o f w i t h f o u r s m a l l d o t s a t or below b u l l a .2, 2. Penes t u b e - l i k e , t i p s n ot i n c u r v e d P e n t a q e n ja W a l s h Penes broader a t base t h a n a t apex, t i p s more or l e s s i n c u r v e d . . . Hexaqenia Walsh Key To Nymphs 1. F r o n t a l p r o c e s s o f head b i f i d Ephemera L i n n a e u s F r o n t a l p r o c e s s o f head e n t i r e and t r u n c a t e , c o n i c a l , o r rounded.. Hexaqenia Walsh GENUS EPHEMERA LINNAEUS Ephemera, Needham, 1935, The B i o l o g y o f M a y f l i e s , 246 ( B i b l i o g r a p h y ) A d u l t : Moderate s i z e d m a y f l i e s ; eyes of male s m a l l , s e p a r a t e d a p i c a l l y by a d i s t a n c e a t l e a s t as g r e a t as the d i a m e t e r o f the eyes; f o r e l e g of male alm o s t as l o n g as the body; femur l / 2 or l e s s t h e l e n g t h o f the t i b i a which i s e q u a l t o or s l i g h t l y l e s s than the l e n g t h o f the t a r s u s ; 2nd t a r s a l j o i n t the l o n g e s t ; i n h i n d l e g of b o t h sexes -205-fernur 3/4 the l e n g t h o f the t i b i a : f o r e w i n g s w i t h c r o s s v e i n s crowded a t and below the b u l l a ; dark band on f o r e w i n g from b u l l a to M; v a r i a b l e c l o u d s i n both w i n g s ; i n h i n d wing, IYI2 o f t e n detached from IY11 a t base, and d i r e c t e d toward the Cu; 2nd f o r c e p s j o i n t s t r o n g l y bowed, b e a r i n g a b a s a l e x t e n s i o n on the i n n e r margin:, penes i r r e g u l a r l y r o d - l i k e , s e p a r a t e d near base, a l m o s t p a r a l l e l , w i t h a l o n g s p i n e on the i n n e r margin o f each d i v i s i o n ; a p i c a l margin o f the s u b a n a l p l a t e of the female w i t h a U-shaped median c l e f t ; t a i l s t h r e e , e q u a l i n l e n g t h . Nymph: F r o n t a l p r o c e s s o f head b i f i d ; . m a n d i b u l a r t u s k s s l e n d e r , the margins smooth; m a x i l l a r y p a l p i 3 - j o i n t e d , s l e n d e r , l o n g , 2nd and 3 r d j o i n t s f r i n g e d w i t h l o n g h a i r s ; g a l e a - l a c i n i a s l e n d e r and p o i n t e d a p i c a l l y ; l a b i a l p a l p i 3 - j o i n t e d , the a p i c a l j o i n t widened a p i c a l l y w i t h the margin t r u n c a t e . Genotype: Ephemera v u l q a t a L. EPHEMERA SIIYIULANS WALKER Ephemera s i m u l a n s W a l k e r , Needham, 1935, The B i o l o g y of M a y f l i e s , 252 ( B i b l i o g r a p h y ) A d u l t : A dark brown m a y f l y ; head and thorax' deep b l a c k i s h brown; some p a l e m arkings on pronotum and mesonotum; l e g s r e d d i s h brown, j o i n i n g s d a r k e r ; f o r e w i n g t i n g e d w i t h brown, but not h e a v i l y b l o t c h e d or a p p e a r i n g b l a c k i s h ; s t r i p e a t b u l l a deep brown; i n a p i c a l t h i r d of wing are two dark brown c l o u d s , one a t the f o r k of the Rs and the o t h e r a t the f o r k i n the space below, n e a r e r the m a r g i n ; a c l o u d toward the margin from the i n n e r end of t h e b u l l a s t r i p e , and a n o t h e r a t the base of the l o n g i n t e r c a l a r y of the M; a l s o a s m a l l c l o u d between t h i s c l o u d and the b u l l a s t r i p e ; l o n g i t u d i n a l v e i n s dark brown; -206-c r o ' s s v e i n s b l a c k i s h , ; t h o s e i n the c o s t a l , s u b c o s t a l , and r a d i a l spaces w i d e l y margined e x c e p t a t the a p i c e s of the Sc and R; many c r o s s v e i n s i n t he d i s c and near the o u t e r margin w i d e l y margined; h i n d wing v e n a t i o n dark brown; v e i n s i n b a s a l s u b c o s t a l space and the d i s c d a r k - m a r g i n e d , f o r m i n g a number of s m a l l dark s p o t s i n the d i s c ; o u t e r margin w i d e l y t i n g e d w i t h l i g h t brown; abdominal t e r g i t e s p a l e brown, markings b l a c k i s h brown; a l a r g e i r r e g u l a r b l a c k i s on each l a t e r a l a r e a o f each t e r g i t e , based on the a n t e r i o r m a r g i n , the l a t e r a l and p o s t e r i o r edges d e e p l y e m a r g i n a t e , the l a t e r a l edges b l a c k ; the p o s t e r i o r margins o f the b a s a l and m i d d l e t e r g i t e s n a r r o w l y p a l e brown; p a l e brown median a r e a s w i d e s t on m i d d l e t e r g i t e s ; t e r g i t e s 7-9 each w i t h a p a i r of b l a c k submedian s t r e a k s , s h o r t on 7; s t e r n i t e s 1-6 each w i t h dark l a t e r a l t r i a n g l e s which a re w i d e s t p o s t e r i o r l y ; s t e r n i t e s 7-9 w i t h dark l a t e r a l l o n g i t u d i n a l s t r e a k s ; each s t e r n i t e w i t h a p a i r o f s m a l l dark submedian s p o t s and a p a i r o f s h o r t dark o b l i q u e submedian s t r e a k s from the a n t e r i o r m a r g i n ; m i d d l e of the s t e r n i t e 9 p a l e ; t a i l s deep y e l l o w to r e d d i s h brown, j o i n i n g s d a r k e r . Nymph; The f r o n t a l n o t c h r e g u l a r l y rounded; the m a n d i b u l a r t u s k s p r o j e c t beyond the f r o n t a l p r o c e s s a l m o s t t w i c e i t s l e n g t h , t h e o u t e r c u r v e s , i n d o r s a l v i e w , v i s i b l e o u t s i d e the antennae; g i l l s p u r p l i s h g r e y . D i s t r i b u t i o n : New York, M i c h i g a n , M i n n e s o t a , O n t a r i o , Montana, A l b e r t a , I l l i n o i s , Ohio, P e n n s y l v a n i a , Idaho, Wyoming, N o r t h C a r o l i n a , B r i t i s h C o l u mbia. -207-M a t e r i a l Examined; 17 Nymphs, B r i t i s h C o l u mbia: N i c o l a Creek (G.G.E. Scud d e r ) GENUS HEXAGENIA UJALSH He x a q e n i a , Needham,.1935, The B i o l o g y of M a y f l i e s , 258 ( B i b l i o g r a p h y ) A d u l t : Moderate s i z e d to l a r g e m a y f l i e s ; eyes of male moderate to l a r g e , a p p r o x i m a t e d a p i c a l l y or s e p a r a t e d by l e s s than the d i a m e t e r of one eye; i n both s e x e s , upper and l o w e r p o r t i o n s of the eye o f d i f f e r e n t c o l o u r s ; a n t e r i o r margin of pronotum ten d s to c o v e r the p o s t e r i o r margin of the head; f o r e l e g of male s h o r t e r than the body; f o r e femur of male s l i g h t l y l e s s than l / 2 the l e n g t h of the t i b i a , which i s 3/4 the l e n g t h of the t a r s u s ; 2nd t a r s a l j o i n t the l o n g e s t , a l m o s t l / 2 the l e n g t h of the t i b i a ; h i n d l e g of male w i t h femur s l i g h t l y s h o r t e r than the t i b i a ; i n f e m a l e , the j o i n t s a re s u b e q u a l ; c r o s s v e i n s of f o r e w i n g not crowded a t or b e f o r e t h e b u l l a ; c r o s s v e i n s i n d i s c o f one or both wings may be d a r k - m a r g i n e d ; no d i s t i n c t p a t t e r n of dark s p o t s on wings; penes u s u a l l y s e p a r a t e d near base, b r o a d e r a t base than a t apex, t i p s i n c u r v e d ; s u b a n a l p l a t e of female o n l y s l i g h t l y p r oduced a p i c a l l y ; t a i l s two. Nymphs: F r o n t a l p r o c e s s of head e n t i r e , i t s margin t r u n c a t e , c u r v e d , c o n i c a l , o r rounded; m a n d i b u l a r t u s k s l o n g , s l e n d e r , smooth, w i t h no r a s p - l i k e t e e t h , u p c u r v e d , t i p s d i v e r g e n t ; l a b i a l p a l p i 2 - j o i n t e d ; m a x i l l a r y p a l p i and g a l e a - l a c i n i a as i n Ephemera. Genotype: Hexaqenia b i l i n e a t a ( i n B a e t i s ) Say -208-HEXAGENIA LIMBATA (GUERIN) Hexaqenia l i m b a t a ( G u e r i n ) B u r k s , 1953, B u l l . Nat. H i s t . S u rv. 111. Hunt, 1953, B u l l . I n s t . F i s h . Res. No. 4, IKlich. Dept. o f C o n s e r v a t i o n ( b i b l i o g r a p h y . ) A d u l t : A p a l e y e l l o u j m a y f l y ; t h o r a x r e d d i s h brown; pronotum w i t h l a t e r a l b l a c k i s h s t r i p e s ; l e g s y e l l o w , f o r e femur and t i b i a b l a c k i s h ; wings h y a l i n e ; n ot t i n g e d w i t h p a l e b r o w n i s h g r e y ; c o s t a l m a r g i n of the f o r e w i n g a l m o s t as t r a n s p a r e n t as the a r e a behind i t ; no s p o t s on wing s ; o u t e r margin o f h i n d wing brown; abdominal t e r g i t e s y e l l o w w i t h a wide da r k , brown m i d - d o r s a l l i n e ; each t e r g i t e w i t h brown l a t e r a l s t r i p e s b e g i n n i n g a t the a n t e r i o r c o r n e r s and e x t e n d i n g back t o meet the median s t r i p e a t the p o s t e r i o r m a r g i n ; penes hook-l i k e ; t a i l segments p a l e y e l l o w i s h b a s a l l y , dark brown d i s t a l l y . Nymph: F r o n t a l p r o c e s s o f head dome shaped; each p o r t i o n o f 1 s t p a i r o f g i l l s composed of 2 or more f i l a m e n t s . D i s t r i b u t i o n : B r i t i s h C o l umbia No specimens of t h i s s p e c i e s were examined. GENUS PENTAGENIA UJALSH P e n t a q e n i a , Needham, 1935, The B i o l o g y o f M a y f l i e s , 255 ( B i b l i o g r a p h y ) A d u l t : Large m a y f l i e s ; eyes o f male l a r g e , a p p r o x i m a t e d a p i c a l l y ; f o r e l e g o f male o n l y s l i g h t l y l o n g e r than the head and t h o r a x combined; f o r e femur 2/3 t o 3/4 the l e n g t h of the t i b i a ; t a r s u s s l i g h t l y l o n g e r -209-than the t i b i a ; h i n d l e g v e r y s i m i l a r to f o r e l e g ; wing v e n a t i o n much as i n Hexaqenia; c e l l s i n the c o s t a l p r o j e c t i o n o f the h i n d wing may be d i v i d e d by a c r o s s l i n e i n t o two s e r i e s ; penes s i m p l e , r e d - l i k e , u n i t e d o n l y a t base, d i v e r g e n t a p i c a l l y ; s u b a n a i p l a t e of female w i t h a U-shaped median notch on the a p i c a l m a r g i n , and a s h o r t p r o j e c t i o n d i r e c t e d outward and backward a t each o u t e r c o r n e r ; t a i l s t h r e e , m i d d l e one very s h o r t . Nymph: F r o n t a l p r o c e s s o f head b i f i d ; m a n d i b u l a r t u s k s s t o u t , c r e v a t e on upper m a r g i n ; m a x i l l a r y p a l p i 3 - j o i n t e d , s t o u t , the 2nd and 3 r d j o i n t s f r i n g e d w i t h l o n g h a i r s ; g a l e a - l a c i n i a wide and c o n i c a l ; l a b i a l p a l p i 2 - j o i n t e d , the d i s t a l j o i n t l o n g , c l a v a t e , c o v e r e d d e n s e l y w i t h l o n g h a i r s and s e v e r a l l o n g s p i n e s near the t i p s . Genotype: P e n t a q e n i a v i t t i q e r a ( i n P a l i n q e n i a ) UJalsh P e n t a q e n i a sp. 1 A d u l t : A v e r y l a r g e y e l l o w i s h brown m a y f l y ; eyes r e d d i s h i n the d o r s a l l / 4 , b l a c k i n the v e n t r a l 3/4; f o r e l e g s dark brown; wings h y a l i n e ; no s p o t s on win g s ; v e n a t i o n dark brown; p o s t e r i o r margins o f h i n d wings dark; abdominal t e r g i t e s y e l l o w w i t h a dark median s t r i p e ; each t e r g i t e w i t h an o b l i q u e brown s t r i p e from the a n t e r o - l a t e r a l c o r n e r s to the p o s t e r i o r b o r d e r ; each s t e r n i t e w i t h a brown median s t r i p e , w i d e n i n g a n t e r i o r l y ; t a i l s , f o r c e p s dark brown. Nymph: Unknown D i s t r i b u t i o n : B r i t i s h Columbia M a t e r i a l Examined: 1 Male, B r i t i s h C o l u m b i a , Summerland, VI.20.58 £K. T a y l o r ) , -210-1 male, B r i t i s h C o l u m b i a : Vernon, IX.6.48 (D. E v a n s ) , 1 Male, B r i t i s h C o l u m b i a : Summerland, V I I I . ? . 5 7 , 1 M a l e , B r i t i s h C o l u m b i a : Okanagan Lake, V I I I . 8 . 3 5 ( 3 . L . McHugh) -211 '' £JL '^£M^^J.JQ.J^_AJi2.^-£S.Ji£.'k'LLS_io.w.s, T h i s t h e s i s encompasses a taxonomic i n v e s t i g a t i o n of the Ephemeroptera of B r i t i s h C o l u m b i a , a group o f i n s e c t s u/hich has been c o m p l e t e l y n e g l e c t e d i n t h i s p r o v i n c e . The c o n s i d e r a b l e s t r u c t u r a l v a r i a t i o n among the h i g h e r r a n k s of the Ephemeroptera and t h e c o n s t a n c y of taxonomic c r i t e r i a w i t h i n each s p e c i e s p r o v i d e t h e t a x o n o m i s t w i t h a r e w a r d i n g o r d e r f o r s t u d y . In t he ' a d u l t s , p a r t i c u l a r l y u s e f u l c r i t e r i a i n c l u d e the d i s t i n c t and e a s i l y i d e n t i f i a b l e wing v e n a t i o n , the s t r u c t u r e o f the compound e y e s , t h e morphology o f t h e l e g s , the shape o f the male g e n i t a l i a , and the c o l o u r p a t t e r n of t h e body. I d e n t i f i c a t i o n i s f a c i l i t a t e d i f specimens of both s e x e s a re a v a i l a b l e f o r s t u d y , . as a l l o f t h e s e c h a r a c t e r i s t i c s e x h i b i t some s e x u a l dimorphism i n a number of s p e c i e s . The p o s i t i o n of the o c e l l i , t he wing c o l o u r , the l e n g t h o f the t a i l s , t he form o f the antennae, and the g e n e r a l c o l o u r o f the i n s e c t a r e l e s s v a l u a b l e taxonomic f e a t u r e s . The p r i m a r y taxonomic c h a r a c t e r i s t i c s o f t h e nymphs are the shape o f the,body, the m o d i f i c a t i o n s o f the m o u t h p a r t s , and the type o f g i l l s . The d e n t i c u l a t i o n and shape of the c l a w s , t h e number, c o l o u r p a t t e r n , and v e s t i t u r e of the t a i l s , and the c o l o u r p a t t e r n of the t e r g i t e s a r e a l s o e s p e c i a l l y u s e f u l f o r i d e n t i f i c a t i o n . The s t r u c t u r e o f the compound e y e s , o c e l l i , antennae, and l e g s are of l i m i t e d v a l u e . I n c l u d e d i n t h i s paper i s a c h e c k l i s t o f a l l s p e c i e s r e p o r t e d o r c o l l e c t e d i n B r i t i s h C o l u m b i a , c o n s i s t i n g o f 146 s p e c i e s i n 23 g e n e r a ; keys to a d u l t s and nymphs; d e s c r i p t i o n s o f t a x o n o m i c a l l y -212-p e r t i n e n t c r i t e r i a o f the a d u l t s and nymphs', and some a c c o u n t o f the e c o l o g y of tho s e specimens c o l l e c t e d by the a u t h o r on the A l o u e t t e R i v e r . A l t h o u g h the e c o l o g y of the m a y f l i e s has not been e x t e n s i v e l y i n v e s t i g a t e d d u r i n g t h i s s t u d y , c e r t a i n f a c t s and t r e n d s have been o b s e r v e d . No p r e f e r e n c e on the p a r t o f the nymphs f o r e i t h e r the m i d d l e or edges of the r i v e r was d e t e r m i n e d . However, s i n c e t h e A l o u e t t e R i v e r i s g e n e r a l l y narrow, between twenty and f o r t y f e e t i n w i d t h , t h e r e i s i n most p l a c e s l i t t l e v a r i a t i o n i n c u r r e n t o r c o m p o s i t i o n o f t h e stre a m bed between the m i d d l e and the edges. At the w i d e s t p a r t of t h e r i v e r , near the mouth, s a m p l i n g was s u c c e s s f u l o n l y a t the edges, so t h a t no co m p a r i s o n w i t h the m i d d l e was p o s s i b l e . Because of the s a m p l i n g methods, a c l e a r i n d i c a t i o n of the p r e f e r e n c e o f v a r i o u s nymphs f o r p a r t i c l e s i z e o f the m a t e r i a l o f the s t r e a m bed was not o b t a i n a b l e . In most l o c a t i o n s mud, sand, f i n e and c o a r s e g r a v e l , and r o c k s of a l l s i z e s were p r e s e n t , and at many s a m p l i n g s t a t i o n s t h e r e were a l s o b o u l d e r s and b e d r o c k . The use of the d i p net p r e c l u d e d the p o s s i b i l i t y of o b s e r v i n g the e x a c t e c o l o g i c a l n i c h e o f the nymphs c o l l e c t e d . lYIost s p e c i e s t a k e n i n the A l o u e t t e R i v e r were found i n l o c a t i o n s c o n t a i n i n g a l l t y p e s of stream bed from mud to bedr o c k . However, Epeorus s p. 2, Epeorus sp.4, E p h e m e r e l l a t e r e s a and E p h e m e r e l l a d o d d s i were never found i n mud or sand. C a e n i s s p . 1. S i p h l o n u r u s sp. 1, C a l l i b a e t i s s p . 1, and C e n t r o p t i l u m s p . 2 were found p r e d o m i n a n t l y i n mud and s i l t , i n l o c a t i o n s where t h e r e was o c c a s i o n a l sand, g r a v e l , o r r o c k s . -213-H e p t a g e n i a sp. 3 was never found i n sand. E p h e m e r e l l a l o d i was u s u a l l y t a k e n i n q u i e t water from mud and s i l t , a l t h o u g h i n one case some nymphs were c o l l e c t e d from a r i p p l y s t r e a m , amongst g r a v e l , r o c k s and b o u l d e r s . Four s p e c i e s : f-'N.eocloeon sp. 1, E p h e m e r e l l a  i n e r m i s , P a r a l e p t o p h l e b i a sp. 1 and P a r a l e p t o p h l e b i a s p . 2 were t a k e n , among o t h e r p l a c e s , from a q u i e t , c l a y - b o t t o m e d p o o l . IKlost o f the s p e c i e s o f nymphs t a k e n i n the A l o u e t t e R i v e r were found i n a l l c u r r e n t s , from q u i e t water t o t u r b u l e n t r a p i d s . Four s p e c i e s , however: E p h e m e r e l l a t e r e s a , E p h e m e r e l l a d o d d s i , Epeorus s p. 2, and Epeorus sp..4, were found o n l y i n a r a p i d , t u r b u l e n t c u r r e n t . Three s p e c i e s : C a e n i s s p. 1, S i p h o n u r u s sp. 1 and C e n t r o p t i l u r a sp. 2 were taken o n l y i n q u i e t , slow w a t e r . On the o t h e r hand, i.Nsocloeon sp. 1, E p h e m e r e l l a l o d i , C a l l i b a e t i s  s p . 1, P a r a l e p t o p h l e b i a b i c o r n u t a , H e p t a q e n i a s p. 3 and B a e t i s s p . 1 were never found i n r a p i d water, and E p h e m e r e l l a s p i n i f e r a , Epeorus s p . 3 and B a e t i s s p . 1 were never t a k e n i n q u i e t or slow w a t e r . Burks (1953) s t a t e s t h a t Hexaqenia l i m b a t a p r e f e r s l a r g e s l ow r i v e r s and m o d e r a t e l y s i z e d f a i r l y r a p i d r i v e r s ; Stenonema sp. and H e p t a q e n i a s p . p r e f e r m o d e r a t e l y s i z e d , f a i r l y r a p i d r i v e r s and s m a l l r a p i d r i v e r s or c r e e k s ; Ephemera s i m u l a n s p r e f e r s s m a l l r a p i d r i v e r s o r c r e e k s and l a r g e l a k e s ; and L e p t o p h l e b i a n e b u l o s a , L. c u p i d a and T r i c o r y t h o d e s sp. p r e f e r temporary ponds, u s u a l l y a l o n g the .margins o f s t r e a m s , w i t h a reduced c u r r e n t o r none. Some s p e c i e s o f nymphs were t a k e n d u r i n g the e n t i r e y e a r , w h i l e o t h e r s were taken o n l y d u r i n g p e r i o d s r a n g i n g from one to -214-seven months. T h i s i s p r o b a b l y not s i g n i f i c a n t , as t h i s s i t u a t i o n c o u l d too e a s i l y be due to chance. There i s a p o s s i b i l i t y t h a t some s p e c i e s become more a c t i v e d u r i n g c e r t a i n t i m e s of the y e a r , but as t h o s e s p e c i e s ( e x c e p t f o r E p h e m e r e l l a f l a v i l i n e a ) c o l l e c t e d d u r i n g a l i m i t e d p a r t of t h e year mere t a k e n d u r i n g t h e summer months, i t was q u i t e p r o b a b l y due to the i n c r e a s e d a c t i v i t y of t h e c o l l e c t o r . Almost a l l o f the specimens were taken a t depths o f one to t h r e e f e e t . T h i s , however, i s a g a i n not s i g n i f i c a n t , as the use of a S u r b e r Sampler or d i p n e t i s not f e a s i b l e a t depths much g r e a t e r than t h i s . Dr. G.G.E. Scudder has c o l l e c t e d e x t e n s i v e l y i n the l a k e s o f the C h i l c o t i n , C a r i b o o and N i c o l a V a l l e y r e g i o n s . He d e t e r m i n e d the pH and t h e s a l i n i t y o f each l o c a t i o n from which he sampled. A l l the l a k e s were n e u t r a l o r a l k a l i n e , r a n g i n g from a pH of 6.84 t o 10.55, the m a j o r i t y r a n g i n g up from pH 7.53. No c o r r e l a t i o n was found i n the p r e s e n t s t u d y between the s p e c i e s c o l l e c t e d and the pH o f the en v i r o n m e n t , o r between the s p e c i e s c o l l e c t e d and the s a l i n i t y o f the l a k e . The amount o f m a t e r i a l a v a i l a b l e f o r stu d y was l i m i t e d , and t h e r e f o r e t h i s paper does not p r o v i d e a complete a c c o u n t of the Ephemeroptera o f B r i t i s h C olumbia. R a t h e r , i t i s i n t e n d e d as a b a s i s f o r f u r t h e r work. F i r s t l y , more complete s e a r c h of the l i t e r a t u r e and e x a m i n a t i o n o f type m a t e r i a l may p r o v i d e i d e n t i t i e s t o some o f the 62 unknown s p e c i e s r e c o r d e d h e r e i n . The r e a r i n g of u n i d e n t i f i e d nymphs t o a d u l t s may det e r m i n e the i d e n t i t y o f o t h e r s . T h i s may be a c h i e v e d by submerging cages o f t h e nymphs i n s t r e a m s , o r w i t h more d i f f i c u l t y , r e a r i n g them i n a r t i f i c i a l -215-s t r e s m s i n the l a b o r a t o r y . Those specimens r e m a i n i n g u n i d e n t i f i e d s h o u l d then be more c o m p l e t e l y d e s c r i b e d and named. S e c o n d l y , a g r e a t d e a l of a d d i t i o n a l c o l l e c t i n g i s n e c e s s a r y t o complete our knowledge of t h i s group i n t h i s p r o v i n c e . L i t t l e i s known, as y e t , of the b i o l o g y and e c o l o g y of many s p e c i e s . F u r t h e r work i n t h e s e f i e l d s would be i l l u m i n a t i n g . The " p r e f e r e n c e " o f t h e v a r i o u s s p e c i e s f o r l a k e s and r i v e r s , r a t e o f c u r r e n t , degree of t e m p e r a t u r e , s a l i n i t y and pH of the environment i s l a r g e l y unknown. C.H. E r i k s e n (1963a, 1963b) has c o n t i n u e d the r e s e a r c h of 3.P. L i n d u s k a (1942) on the p r e f e r e n c e of some nymphs f o r p a r t i c l e s i z e of the s u b s t r a t e . C o l l e c t i n g t e c h n i q u e s make i t d i f f i c u l t t o s t u d y t h i s a s p e c t i n t h e f i e l d , and t h e r e f o r e h i s e x p e r i m e n t a l approach i s of g r e a t v a l u e . A c o n t i n u a t i o n and e x p a n s i o n of t h i s t o o t h e r s p e c i e s would be b e n e f i c i a l . The d i v e r s i t y among body forms of the nymphs would make a study of t h e r e l a t i o n s h i p between body form and environment of v a l u e . Research a l o n g t h i s l i n e has a l r e a d y been i n t r o d u c e d by G.S. Dodds and F.L. H i s a ^ (1924a, 1924b). The minute d i f f e r e n c e s between some s p e c i e s ( ? ) a f f o r d s an o p p o r t u n i t y t o s t u d y the p o s s i b i l i t y o f g e o g r a p h i c v a r i a t i o n w i t h i n t h i s o r d e r of i n s e c t s . -216-S U ffl IYJ A R Y T h i s paper was u n d e r t a k e n to amalgamate the e x i s t i n g knowledge of the Ephemeroptera of B r i t i s h Columbia and t o c o n t r i b u t e to i t , to c l a r i f y the taxonomy c o n s i s t e n t w i t h the newer i d e a s o f c l a s s i f i c a t i o n o f t h i s group, and t o p r o v i d e a b a s i s f o r f u r t h e r i n v e s t i g a t i o n . Whereas the taxonomy of the o r d e r has been w e l l s t u d i e d i n the U n i t e d S t a t e s , i t has been l a r g e l y n e g l e c t e d i n Canada, and p a r t i c u l a r l y i n B r i t i s h C o l u m b i a . The Ephemeroptera p r o v i d e a s a t i s f y i n g group w i t h which t o work as they e x h i b i t d i s t i n c t and c o n s i s t e n t taxonomic c r i t e r i a , a l t h o u g h a c o n s i d e r a b l e degree of s e x u a l dimorphism makes the c o n s t r u c t i o n of keys d i f f i c u l t . The system of c l a s s i f i c a t i o n p roposed by Edmunds and T r a v e r (1954) i n which the t h r e e f a m i l i e s H e p t a g e n i i d a e , Ephemeridae, and B a e t i d a e a r e r e p l a c e d by the f i v e s u p e r f a m i l i e s Heptagen-o i d e a , L e p t o p h l e b i o i d e a , C a e n o i d e a , Ephemeroidea, and P r o s o -p i s t o m a t o i d e a , i s employed. A l l but the l a s t a r e r e p r e s e n t e d i n t h i s p r o v i n c e . 146 s p e c i e s i n 23 genera have been r e c o r d e d from B r i t i s h C o lumbia. Df t h e s e , 62 s p e c i e s are as y e t . n o t i d e n t i f i e d by t h e a u t h o r and have been d e s i g n a t e d by number. A c h e c k l i s t , k e y s , and d e s c r i p t i o n s o f t a x o n o m i c a l l y p e r t i n e n t c r i t e r i a o f a l l r e c o r d e d s p e c i e s and h i g h e r r a n k s are i n c l u d e d h e r e i n . A c u r s o r y i n v e s t i g a t i o n of the e c o l o g y of the nymphs i n v o l v e d r e g u l a r c o l l e c t i o n s from 20 l o c a t i o n s , chosen to p r o v i d e a l l -217-t y p e s o f s u b s t r a t e and r a t e s of c u r r e n t f l o w , on the A l o u e t t e R i v e r , near Haney. No " p r e f e r e n c e " f o r the m i d d l e or edges of the r i v e r was e x h i b i t e d by the nymphs. Most s p e c i e s were taken from a l l t y p e s o f stream bed. T h i s , however, i s not s i g n i f i c a n t , as the use of a d i p net does not l e n d i t s e l f t o an a c c u r a t e d e t e r m i n a t i o n of p a r t i c l e s i z e " p r e f e r e n c e " . The e x p e r i m e n t a l approach t o t h i s problem o f C.H. E r i k s e n (1963) i s of more v a l u e than f i e l d o b s e r v a t i o n s . There i s no c o r r e l a t i o n between the s p e c i e s of nymphs and the pH or the s a l i n i t y o f the e n v i r o n m e n t . In o r d e r to e x t e n d our knowledge of the Ephemeroptera of B r i t i s h C o l u m b i a , i t would be d e s i r a b l e t o c o l l e c t i n h i t h e r t o untouched r e g i o n s o f the p r o v i n c e , and t o f u r t h e r i n v e s t i g a t e the i d e n t i t i e s of the 62 u n i d e n t i f i e d s p e c i e s by f u r t h e r r e s e a r c h i n t o the l i t e r a t u r e , e x a m i n a t i o n o f type m a t e r i a l , and r e a r i n g of nymphs. New s p e c i e s s h o u l d then be d e s c r i b e d and named. F u r t h e r s t u d y of the e c o l o g y and b i o l o g y of members of t h i s o r d e r would be r e w a r d i n g . -218-L I ILIL h. I LL £ I £ 1 1 1 2 A l l e n , R.K., and G.F. Edmunds, Or., 1957. A R e v i s i o n o f The Genus E p h e m e r e l l a (Ephemeroptera: E p h e m e r e l l i d a e ) I . The Subgenus Timpanoqa. Can. E n t . -.91:51-58. 1961. A R e v i s i o n o f t h e Genus E p h e m e r e l l a (Ephemeroptera: E p h e m e r e l l i d a e ) I I . The Subgenus C a u d a t e l l a . Ann. E n t . S o c Amer. 54:603-612, 1961. A R e v i s i o n o f the Genus E p h e m e r e l l a (Ephemeroptera: E p h e m e r e l l i d a e ) I I I . The Subgenus A t t e n u a t e l l a . Dourn. Kansas Ent. Soc. 34:161-173. 1962. A R e v i s i o n o f the Genus E p h e m e r e l l a (Ephemeroptera: E p h e m e r e l l i d a e ) IV. The Subgenus D a n n e l l a . Oourn. Kansas Ent . Soc. 35:333-338. 1962. A R e v i s i o n o f the Genus E p h e m e r e l l a (Ephemeroptera: E p h e m e r e l l i d a e ) V. The Subgenus D r u n s l l a . IMsc. Pub. E n t . Soc. Amer. .3(5) :145-180. 1963. A R e v i s i o n , o f the Genus E p h e m e r e l l a (Ephemeroptera: E p h e m e r e l l i d a e ) V I . The Subgenus S e f r a t e l l a . Ann. E n t . Soc. Amer. 56(5):583-600. . 1963. H R e v i s i o n o f the Genus E p h e m e r e l l a (Ephemeroptera: E p h e m e r e l l i d a e ) V I I . The Subgenus E u r y l o p h e l l a . Can. E n t . 95 ( 6 ) : 597-623. B e r n e r , L., 1940, B a e t i n e m a y f l i e s from F l o r i d a ( E p h e m e r o p t e r a ) . F l o r i d a E n t . 23:33-45; 49-62. 1950. The m a y f l i e s of F l o r i d a . U n i v . F l o r i d a S t u d i e s , B i o l . S c i . S e r i e s 4 ( 4 ) , 1953. New m a y f l y r e c o r d s from F l o r i d a and a d e s c r i p t i o n o f a new s p e c i e s . F l o r i d a E n t . 36:145-9. 1955. A new s p e c i e s of P a r a l e p t o p h l e b i a from the S o u t h e a s t (Ephemeroptera: L e p t o p h l e b i i d a e ) . P r o c . E n t . Soc. Wash. 57:245-7. 1956. The Genus Neoephemera i n N o r t h America (Ephemeroptera: Neoephemeridae). Ann. Ent. Soc. Amer. 49:33-42. B u r k s , B.D., 1946. New Heptagenine m a y f l i e s . ' Ann. E n t . Soc. Amer. 39:607-615. 1949. New s p e c i e s of E p h e m e r e l l a from I l l i n o i s ( E p h e m e r o p t e r a ) . Can. E n t . 79:232-6. 1953. The m a y f l i e s , or Ephemeroptera, of I l l i n o i s . B u l l . 111. Nat. H i s t . S u r v . 26:1-216. -219-Day, UJ.C, 1952. New s p e c i e s and n o t e s on C a l i f o r n i a m a y f l i e s ( E p h e m e r o p t e r a ) , Pan-Pac. En t . 28:17-39. 1953. A new m a y f l y genus from C a l i f o r n i a ( E p h e m e r o p t e r a ) . Pan-Pac. Ent. 29:19-24. 1954. New s p e c i e s and n o t e s on C a l i f o r n i a m a y f l i e s , I I . Pan-Pac. Ent. 30:29-34. 1955. New genera of m a y f l i e s from C a l i f o r n i a ( E p h e m e r o p t e r a ) . • Pan-Pac. E n t . 31:121-37. Dodds, G.S. and F.L. Hisaw, 1924. E c o l o g i c a l s t u d i e s of a q u a t i c i n s e c t s : I . S i z e of r e s p i r a t o r y organs i n r e l a t i o n t o e n v i r o n m e n t a l c o n d i t i o n s . E c o l o g y , 4: 262-271. 1924. E c o l o g i c a l s t u d i e s of a c q u a t i c i n s e c t s . I I . A d a p t a t i o n s of m a y f l y nymphs to s w i f t s t r e a m s . E c o l o g y , 5: 137-148. E a t o n , A.E., 1883-88. A r e v i s i d n a l monograph of r e c e n t Ephemeridae o r m a y f l i e s . T r a n s . L i n n . Soc. London, Sec. S e r . Z o o l . 3: 1-352. 1901. Ephemeridae c o l l e c t e d by H e r r . E. S t r a n d i n South and A r c t i c Norway. E n t . Month, mag. 37:252-5. Edmunds, G.F. J r . , 1959. S u b g e n e r i c groups w i t h i n the m a y f l y genus E p h e m e r e l l a (Ephemeroptera: E p h e m e r e l l i d a e ) . Ann. E n t . Soc. Amer. 52:543-547. 1962. T h e . p r i n c i p l e s a p p l i e d i n d e t e r m i n i n g the h i e r a r c h i c l e v e l o f the h i g h e r c a t e g o r i e s of Ephemeroptera. S y s t e m a t i c Z o o l o g y , 11:22-31. Edmunds, G.F. Or. and R.K.. A l l e n , 1957. A c h e c k l i s t of t h e Ephemer-o p t e r a of N o r t h America n o r t h of M e x i c o . Ann. Ent. Soc. Amer. 50: 317-324. Edmunds, G.F. Dr. and 3.R. T r a v e r , 1954. An o u t l i n e c f a r e c l a s s i -f i c a t i o n o f the Ephemeroptera. P r o c . E n t . Soc. Ulash. 56: 236-240. E r i c s e n , , ( X . , 1963, The R e l a t i o n o f Oxygen Consumption to S u b s t r a t e P a r t i c l e S i z e i n Two B u r r o w i n g M a y f l i e s . 0. Exp. B i o l . 40: 447-453. Eri k s ' e n , C.H., 1963. R e s p i r a t i o n R e g u l a t i o n i n Ephemera s i r n u l a n s UJalker and Hexaqenia l i m b a t a ( S e r v i l l e ) ( E p h e m e r o p t e r a ) . 0. Exp. B i o l . 40:455-467. Id e , F.P. 1930. C o n t r i b u t i o n to the b i o l o g y of O n t a r i o m a y f l i e s w i t h d e s c r i p t i o n s of new s p e c i e s . Can. E n t . 62: 204-13, 218-31. . -220-1937. D e s c r i p t i o n s o f e a s t e r n N o r t h American s p e c i e s o f B a e t i n e m a y f l i e s w i t h p a r t i c u l a r r e f e r e n c e to the nymphol s t a g e s . Can. E n t . 69:219-31, 235-43. 1954. The nymph of R i t h r o q e n a i m p e r s o n a t a (Ephemerida) and a new c l o s e l y r e l a t e d s p e c i e s from the same l o c a l i t y i n S o u t h e r n O n t a r i o . Can. Ent. 86:348-56. L i n d u s k a , J.P., 1942. Bottom t y p e s as a f a c t o r i n f l u e n c i n g the l o c a l d i s t r i b u t i o n of m a y f l y nymphs. Can. Ent. 74:26-30. Mayo, U.K., 1939. New 'western Ephemeroptera. Pan-Pac. E n t . 15: 145-154. 1951. New 'western Ephemeroptera I I . Pan-Pac. Ent. 27:121-125. 1952. New w e s t e r n Ephemeroptera I I I . Pan-Pac. Ent. 28:93-103. 1952. New Western ••.Ephemeroptera IU. Pan-Pac. Ent. 28:179-186. (YlcDunnough, 3., 1921. Two new Canadian m a y f l i e s ( E p h e m e r i d a e ) . Can. E n t . 53: 117-120. 1936. A new a r c t i c B a e t i d ( E p h e m e r o p t e r a ) . Can. Ent. 68: 33-35. 1936. F u r t h e r n o t e s on the genus Ameletus w i t h d e s c r i p t i o n s of new s p e c i e s . ( E p h e m e r o p t e r a ) . Can. Ent. 68:207-11. 1938. New s p e c i e s of N o r t h American Ephemeroptera w i t h c r i t i c a l n o t e s . Can. Ent. 70:23-34. 1939. New B r i t i s h Columbian Ephemeroptera. Can. Ent. 71:49-54. 1942. An a p p a r e n t l y new T h r a u l o d e s from A r i z o n a ( E p h e m e r i d a ) . Can. Ent. 74:117. 1943. A new Cinyqmula from B r i t i s h Columbia ( E p h e m e r o p t e r a ) . Can. Ent. 75:3 Needham, 0 C , 3.R. T r a v e r , and Y i n - C h i Hsu., 1935. The B i o l o g y of M a y f l i e s w i t h a S y s t e m a t i c Account o f N o r t h American S p e c i e s . Comstock, I t h a c a , N.Y. S p i e t h , H.T., 1933. The Phylogeny o f Some M a y f l y Genera. 3. N.Y. E n t . Soc. 41:55-86, 327-391. 1938. A method of r e a r i n g Hexagenia nymphs. Ent. News. 49:29-32. 1938. Two i n t e r e s t i n g m a y f l y nymphs w i t h a d e s c r i p t i o n o f a new s p e c i e s . Amer. Mus. N o v i a t e s 970:1-7. -221-1938. Taxonomic s t u d i e s on the Ephemerida. I : D e s c r i p t i o n s o f New North American s p e c i e s . Amer. fflus. N o v i a t e s . 1002: 1-11. 1940. The N o r t h American Ephemeropterans s p e c i e s o f F r a n c i s l U a l k e r . Ann. Ent. Soc. Amer. 33:324-38. 1941.. The N o r t h American Ephemeropteran s p e c i e s of the Rev. A.E. E a t o n . Ann. E n t . Soc. Amer. 34:87-98. 1941. Taxonomic s t u d i e s on the Ephemeroptera I I . The genus Hexaqenia . Amer. M i d . Nat. 24 (2):233-280. 1947. Taxonomic s t u d i e s on the Ephemeroptera IV. The genus Stenonema. Ann. Ent. Soc. Amer. 40 ( l ) : 8 7 - 1 2 2 . S p r u l e s , ID. IYI., 1947. An e c o l o g i c a l i n v e s t i g a t i o n o f stream i n s e c t s i n A l g o n q u i n P a r k , O n t a r i o . U n i v . Toronto S t u d i e s , B i o l . S e r . 56, Pub. Ont. E i s h . Res. Lab. 69:1-81. U p h o l t , 111.IYI. 1936. A new s p e c i e s o f m a y f l y from C a l i f o r n i a (Epheme B a e t i d a e ) . Pan-Pac. E n t . 12:120-2. 1937. Two new m a y f l i e s from the P a c i f i c C o a s t . Pan-Pac. Ent. 13:85-88, -222-PLATE I A diagram of t h e main t o p o g r a p h i c f e a t u r e s of a m a y f l y wing (based on a f o r e wing o f I r o n o p s i s  permaqnus), c r o s s v e i n s of the m i d d l e f i e l d m o s t l y o m i t t e d . The numerals 1, 2, and 3 d e s i g n a t e s u c c -e s s i v e f o r k s i n the t r i p l e t r i a d o f the r a d i a l s e c t o r ; f o r k s 2 and 3 are not p r e s e n t i n the h i n d wing of r e c e n t m a y f l i e s . Of, o u t e r f o r k of Rs. ( a f t e r Needham, T r a v e r , and Hsu, 1935). R e p r e s e n t a t i v e mouthparts of t h e m a y f l y nymph. A, r i g h t m a n d ible o f B l a s t u r u s ; - s p . ; B, m a x i l l a of L e p t o p h l e b i a s p . ; C, l a b i u m of S i p h l o n u r u s sp. ( a f t e r S p i e t h , 1933). PL RTE' I -223-PLATE I I Wale g e n i t a l i a of some Heptagenine and B a e t i d m a y f l i e s , ( n o t drawn to s c a l e ) , ( a f t e r Needham, T r a v e r , and Hsu, 1935). P L A T F I I . £ f> e o r v s J f e. n 9 n e m <t He f t o j e n i'fit Jimp licoiJef R i t h r o j a n f J e w r a / }^ P a ft f I J 

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