Fig. 6:23, Female terminolia of Nemouro in ventrol view. 

 a, cofaracroe; b, besametsa; c, cornufo (Ricker, 1943). 



— Gills constricted only at the base if at all (a slight 

 subterminal constriction occasionally in haysi) 7 



7. Produced part of the 7th sternite usually light-colored 

 and narrowly rounded, almost semicircular; Yukon to 

 California, Utah, Wyoming, and Colorado 



oreqonensis Claassen 1923 



— Produced part of the 7th sternite dark colored, at least 

 along the broadly rounded or nearly straight hind 

 margin; Alaska to California, Utah, Wyoming, and 

 Colorado haysi Ricker 1952 



8. Notch of the 8th sternite in a sclerotized band set 

 before the hind margin of the segment (except in the 

 eastern wui); North America generally except the plains 

 and Pacific Coast . . (subgenus Amphinemura Ris 1902) 



— Notch of the 8th sternite terminal 



(subgenus Malenka Ricker 1952) 9 



9. Seventh sternite produced and rounded but lacking a 

 nipple; 8th sternite greatly swollen, considerably 

 produced, and often very irregular in shape at either 

 side of the notch; the anterior third of the notch border- 

 ed by a square patch of heavy sclerotization (fig. 

 6:23c); British Columbia to California 



cornuta Claassen 1923 



— Produced part of the 7th sternite bearing a distinct 

 nipple, the base of which is often anterior to the hind 

 margin of the sternite (best seen in side view; some- 

 times obscure in depressa); 8th sternite not as above 



10 



10. Median notch not completely bisecting 8th sternite 



11 



— Median notch completely bisecting 8th sternite; south- 

 western California biloba Claassen 1923 



11. Notch of the 8th sternite extending about halfway 

 through the sternite, nowhere margined by extra sclero- 

 tization 12 



— Notch of the 8th sternite extending almost to the ante- 

 rior margin near which it is narrowly margined by heavy 

 sclerotization (fig. 6:246); Utah to New Mexico 



coloradensis Banks 1897 



12. Nipple of the 7th sternite low, inconspicuous, often 

 scarcely recognizable; its base confluent with the hind 

 margin of the sternite (fig. 6:24a); Oregon and California 



depressa Banks 1898 



— Nipple of the 7th sternite erect, easily distinguished in 

 side view at least, its base set somewhat anterior to 

 the hind margin of the sternite (fig. 6:24c); Alberta and 



British Columbia to California and New Mexico 



(synonym: lobata Frison 1936) calif ornica Claassen 1923 



13. Veins A, and A 2 united near the margin of the wing; 

 7th sternite produced over the full length of the 8th 

 (subgenus Soyedina Ricker 1952) 14 



— Veins A, and A 2 not united (sometimes united in ob- 

 scura, a small species occurring in Washington and 

 Oregon in which the 7th sternite does not cover the 8th) 



15 



14. Subgenital plate of the 7th sternite more broadly round- 

 ed; California and Nevada. . .nevadensis Claassen 1923 



— Subgenital plate less broadly rounded; British Columbia 



to Oregon (synonym: 



N. tuberculata Frison 1937) producta Claassen 1923 



167 

 Jewett: Plecoptero 



15. Wings mostly dark with a rli-w <>r relatively < !< 

 across the middle of tl liter Meld 16 



— Wings entirely clear or with .some or all veins m.u- 

 with brown or with a marginal or central dark ;...t ill 

 the level of the cord 19 



16. Terminal costal cross vein running between 8c and C, 



proximad of the cord; eastern North America 



(subgenus Paranemoura Needham and Claassen 19 



— Terminal costal cross vein running between U, and C 

 beyond the cord 17 



17. Seventh sternite sclerotized and produced over the full 

 length of the 8th, its hind margin straight to broad 1 J 

 rounded; northern and northeastern North America 



Nemoura, s.s, Pictel 1841 (in part) 



— Seventh sternite only slightly or not at all produced 

 over the 8th (the normally rounded margin of the sub- 

 genital plate of the 8th sternite in Shipsa may be 

 mistaken for the 7th sternite) 18 



18. Eighth sternite with a subgenital plate terminating 

 anterior to the well-developed hind margin and bearing 

 contrasting dark and light bands; Alaska east to Ontario 

 and Maryland 



. .(subgenus Shipsa Ricker 1952) rotunda Claassen 1923 



— Eighth sternite with a terminal subgenital plate not 

 separated from the hind margin of the sternite and 

 uniformly colored (fig. 6:236); southern British Columbia 

 to California and Colorado (sub- 

 genus Prostoia Ricker 1952) besametsa Ricker 1952 



19. Eighth sternite very weak and unsclerotized medialU; 

 7th sternite produced over the full length of the 8th 

 and not laterally excavated; northern and northeastern 

 North America Nemoura, s.s. Pictet 1841 (in part) 



— Eighth sternite sclerotized medially at least near the 

 posterior margin; 7th sternite only slightly or not at all 

 produced (except in Ostrocerca prolongata, found in 

 northeastern North America, where it is excavated 

 laterally) 20 



20. Eighth sternite produced and rounded medially, not 

 notched; 2 squarish patches of sclerotization on the 

 hind margin, separated from the median produced part; 

 known only from Montana 



...(subgenus Lednia Ricker 1952) tumana Ricker 1952 



— Eighth sternite produced and notched or not produced; 

 its lateral sclerotization, if present, continuous with 

 that of the median area 21 



21. Eighth sternite with a narrow median sclerotized band 

 contrasting with the unsclerotized field at either side 



(subgenus Podmosta Ricker 1952) 22 



— Eighth sternite without any median stripe, usually 

 uniformly sclerotized; eastern North America and 

 British Columbia to Oregon 



(subgenus Ostrocerca Ricker 1952) 



22. Median sclerotized stripe of the 8th sternite 3-4 times 

 as long as its greatest breadth, of nearly uniform width 

 throughout; central British Columbia to California and 

 Colorado delicatula Claassen 1923 



— Median sclerotized stripe of the 8th sternite not more 

 than twice as long as its greatest breadth, frequently 

 rather obscure; British Columbia to Wyoming 



decepta Frison 1942 



Fig. 6:24. Female terminalia of Nemouro in ventrol view. 

 o, depressa; b, coloradensis; c, califomico (Needham and 

 Claassen, 1925). 



