160 



Jewett: Plecoptera 



Fig. 6:9 



Wings of: a, Chloroperla terna; b, Kathroperla perdita; c, Hastap 

 (a, Frison, 1942b; b,c, Needham and Claassen, 1925). 



erla brev/s 



6:116); east of Rocky Mountains 



Atoperla Banks 1905 



31. Anal area of fore wing with a single row of cross veins 

 (fig. 6:11c); pronotum with a dark median band; east of 

 Rocky Mountains Perlinella Banks 1900 



— Anal area of fore wing without cross veins except those 

 that form the anal cell; no dark median band on pronotum 



32 



32. Costal margin of fore wing dark and almost unicolorous 

 with rest of wing; 9th ventral abdominal segment of 

 male with a disclike structure or "hammer" in middle 

 of posterior part 33 



— Costal margin of fore wing and base of R. and M yellow- 

 ish contrasting with brownish veins; 9th abdominal seg- 

 ment of male without a disclike structure in middle of 

 posterior part; east of Rocky Mountains 



Perlesta Banks 1906 



33. Tenth tergite of male with prolongations arising from 

 lateral angles (fig. 6:106); western North America 



. Claassenia Wu 1934 



— Tenth tergite of male without prolongations (fig. 6: 10a) 



A crone uria Pictet 184 1 



34. With 2 ocelli; east of Rocky Mountains 



Neoperla Needham 1905 



— With 3 ocelli 35 



35. Male genital hooks extending to anterior border of 8th 

 tergite; east of Rocky Mountains 



N e ophasganophora Lestage 1922 



— Male genital hooks extending at most to posterior 

 margin of 9th tergite (fig. 6:10c); east of Rocky Moun- 

 tains Paragnetina Klapalek 1907 



Key to the Families and Genera of North American 

 Plecoptera Nymphs 



1. Paraglossae and glossae of about equal length (fig. 

 6:4a) suborder FILIPALPIA 2 



— Paraglossae much longer than the glossae (fig. 6:46) 



suborder SETIPALPIA 15 



2. Abdomen without branched gills on the ventral side. 3 



— Branched gills on the ventral side of abdominal seg- 



10, 



ments 1 and 2 PTERONARCIDAE 14 



Form cockroachlike; ocelli 2; thoracic sterna produced 

 posteriorly into thin plates overlapping the segment 

 behind (fig. 6: 126) ' 



PELTOPERLEDAE Peltoperla Needham 1906 



Form typical; ocelli 3; thoracic sterna not produced 

 posteriorly to overlap the segment behind 



NEMOURIDAE 4 



Second tarsal segment much shorter than the first 



(fig. 6:6a) 5 



Second tarsal segment at least as long as the first 



(fig. 6:66) TAENIOPTERYGINAE 13 



Stout nymphs; hind wing pads strongly diverging from 

 the axis of the body 



NEMOURINAE Nemoura Pictet 1841 



Cylindrical elongate nymphs; hind wing pads nearly 



parallel with the axis of the body 6 



Abdominal segments 1 to 9 divided by a membranous 



fold laterally CAPNIINAE 9 



At most only the first 7 abdominal segments divided 



by a membranous fold LEUCTRINAE 7 



Segments 1 to 7 of the abdomen divided laterally by 



a membranous fold 8 



Only the first 5 or 6 abdominal segments divided 



laterally Leuctra Stephens 1835 



Body covered by rather coarse appressed pile, the 

 individual hairs of which are about 1/5 as long as a 

 middle abdominal segment; galea exceeding lacinia 



Megaleuctra Neave 1933 



Body with extremely fine pile, appearing naked; galea 

 not quite reaching the end of the lacinia 



Perlomyia Banks 1906 



Cerci with mesal and lateral fringes of long silky 

 hairs, several to a segment; western North America 



Isocapnia Banks 1938 



Cerci without silky fringes, though sometimes with 



1 or 2 rather long bristles on each segment 10 



Body and appendages densely covered with bristles 

 including several on the subanal lobes; east of Rocky 

 Mountains Paracapnia Hanson 1946 



Fig. 6:10. Dorsal view of male terminalia of: o, jAcroneuri'a Fig. 6:11. o, Wings of Anocroneun'a naomi; b, fore wing of 



theodora; b, Claassenia sabulosa; c, Paragnetina fumosa (a, Atoperla ephyre; c, fore wing of Perlinella drymo (a, Needham 



Needham and Claassen, 1925; b, Ricker, 1938; c, Ricker, 1949). and Broughton, 1927; b, c, Frison, 1935). 



