165 

 Jewett: Plecoptero 



Fig. 6:21. Male terminalia of Nemoura. o, haysi, dorsal view; b, catarocfae, ventral view; 

 c, besamelsa, lateral view (a,c, Ricker, 1952; b, Neave, 1933). 





Key to the Males of the North American Subgenera and 

 California Species of Nemoura 



I. Cerci elongated and heavily sclerotized to the tip, on 

 at least the outer surfaces; the tip sharp or with 2 or 

 more processes 2 



• Cerci membranous or weakly sclerotized (except for a 

 distinct mesobasal process, often sclerotized, in some 

 species of Malenka); the tip blunt, without spines or 

 processes 5 



t. Supra-anal process simple, slender, subacute; subanal 

 lobes broad with a long slender spine mesally; with or 



without gills 3 



Supra-anal process complex, broad; subanal lobes not 

 as above; gills absent 4 



i. Two-branched gills inserted at the sides of the mentum 

 (fig. 6:216); Alberta and British Columbia to Cali- 

 fornia (sub- 

 genus Visoka Ricker 1952) . . .cataractae Neave 1933 



1 No external gills; central California (fig. 6:536) (not 

 assigned to subgenus) spiniloba Jewett 1954 



:. Cerci only a little elongated, membranous on the inner 

 surface; abdominal segments all completely sclerotized 

 and of approximately equal width; northern and north- 

 eastern North America Nemoura, s.s. Pictet 1841 



Cerci long and slender, completely sclerotized; 9th and 

 10th abdominal segments sclerotized and much wider 

 than the weakly sclerotized remaining segments; eastern 



North America and British Columbia to Oregon 



(subgenus Ostrocerca Ricker 1952) 



. No lobe on the 9th sternite 6 



Lobe present at the base of the 9th sternite 7 



I. Terminal slanting costal cross vein between Sc and C; 

 10th tergite not elevated or armed; eastern North Amer- 

 ica 



. (subgenus Paranemoura Needham and Claassen 1925) 

 Terminal slanting cross vein between R| and C; 10th 

 tergite elevated, heavily sclerotized, and armed with 



short spines; known only from Montana 



..(subgenus Lednia Ricker 1952) tumana Ricker 1952 



'. Veins A, and A 2 of the fore wing united a little before 

 their outer end; subanal lobes long, upcurved, and 



flattened in side view 



(subgenus Soyedina Ricker 1952) 8 



Veins A, and A 2 separate at the tip; subanal lobes not 



as above 10 



8. Tergites 2-4 with elevated processes (fig. 6:19); British 



Columbia to Oregon (synonym: 



N. tuberculata Frison 1937) producta Claassen 1923 

 - Tergites 2-4 without processes 9 



10. 

 11, 



12 



13, 



14 



15 



16 



'Adapted from Ricker (1952). 



17, 



Subanal lobes tapering regularly to their broad tips, no 

 notch on the mesal surface when viewed from the side 

 or from behind though there is a broad excavation near 

 the base (fig. 6:20a 1 ); California and Nevada 



nevadensis nevadensis Claassen 1923 



Mesal margin of subanal lobes notched; their tips rather 

 narrow (fig. 6:206); British Columbia to Oregon 



(syronym: N . pseudoproducta 



Frison 1942) nevadensis interrupta Claassen 1923 



Cervical gills present 11 



Cervical gills absent 21 



Gills unbranched except in cinctipes which has gills 

 commonly 5-branched and wings with contrasting clear 

 and pigmented bands 



(subgenus Zapada Ricker 1952) 12 



Gills with 6 or more branches; wings without any clear 



transverse bands 16 



Wings uniformly dark; gills 12-15 times as long as 

 wide (fig. 6:20c); southern Alaska to California, Col- 

 orado, Wyoming frigida Claassen 1923 



Wings conspicuously banded or mostly clear; gills less 



than 10 times as long as wide 13 



Gills branched one to several times (very rarely un- 

 branched); tip of the wings clear (fig. 6:10/); Alaska to 

 California and Alberta to Colorado and Nevada; east to 



Manitoba and South Dakota cinctipes Banks 1897 



Gills simple 14 



Gills constricted at the base and one or more times 

 (usually twice) beyond the base (fig. 6:20a); southern 

 Alaska to California and Utah 



Columbiana Claassen 1923 



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

 subterminal constriction occasionally in haysi) .... 15 

 Subanal lobes quadrangular, the inner terminal angle 

 rather sharp, without any sclerotized knob on the inner 

 membrane (fig. 6:20e); Yukon to California, Utah, 



Wyoming, and Colorado oregonensis Claassen 1923 



Subanal lobes with the inner terminal angle obtuse and 

 rounded so that the lobe appears almost triangular, and 

 bearing a sclerotized knob on the distal lateral corner 

 of the inner membrane (fig. 6:21a); Alaska to California, 



Wyoming, and Colorado haysi Ricker 1952 



Subanal lobes divided almost to the base into 2 parts, 

 one or both of them spinulose; cerci without basal 

 processes; North America generally except on the plains 

 and Pacific Coast ..(subgenus Amphinemoura Ris 1902) 

 Subanal lobes variously modified, never spinulose, 

 cleft, if at all, for less than half their length; cerci 

 with a membranous or sclerotized process mesally near 

 their base (this appears to be distinct from the cercus 

 in some species — more like a process of the 10th 



tergite) (subgenus Malenka Ricker 1952) 17 



Mesobasal lobe of the cercus sclerotized and sharply 



