166 



Jewett: Plecoptera 



Fig. 6:22. Male terminalia of Nemoura in dorsal view, a, 

 decepta; b, caiifornica; c, delicafula; d, biloba; e, cornufa; f, 

 co/oradens/s; g, depressa (a, Frison, 1942a; b-g, Needham and 

 Claassen, 1925> 



pointed and appearing to be a part of the 10th tergite 



18 



— Mesobasal lobe of the cere us rounded and usually 

 membranous 19 



18. Mesobasal lobe directed straight back; outer part of the 



subanal lobes narrow and twice constricted (fig. 6:22e); 

 British Columbia to California. . .cornuta Claassen 1923 



— Mesobasal lobe directed inward and backward; outer 

 part of the subanal lobes broad and not constricted but 

 with a notch on the mesal margin (fig. 6:226); Alberta 

 and British Columbia to California and New Mexico 

 (synonym: N . lobata Frison 1936) 



californica Claassen 1923 



19. Tip of the subanal lobes simple 20 



— Tip of the subanal lobes divided into 2 divergent and 

 and acute prongs (fig. 6:22d)'> southwestern California 



biloba Claassen 1923 



20. Mesobasal lobe of the cercus about twice as broad as 

 the cercus proper and moderately sclerotized (fig. 

 6:22(7); Oregon and California depressa Banks 1898 



— Mesobasal lobe of the cercus no broader than the cercus 

 itself and unsclerotized (fig. 6:22/); Colorado and Utah 

 to New Mexico coloradensis Banks 1897 



21. Sides of the 10th tergite produced into erect spiny 

 incurved processes; wings with alternate clear and 

 pigmented bands; Alaska to Ontario and Maryland 



(sub- 

 genus Shipsa Ricker 1952) rotunda Claassen 1923 



— Sides of the 10th tergite not as above; wings banded or 

 uniformly colored 22 



22. Supra-anal process slender, completely recurved along 

 the 10th and 9th tergites (fig. 6:21c); southern British 



Columbia to California and Colorado 



(subgenus Prostoia Ricker 1952) besametsa Ricker 1952 



— Supra-anal process rather short, thick, complex in 

 structure, and only slightly bent forward 



(subgenus Podmosta Ricker 1952) 23 



23. Supra-anal process with sharp, curved, laterally directed 

 horns near the tip; 10th abdominal tergite only slightly 

 excavated behind (fig. 6:223); British Columbia to 

 Wyoming decepta Frison 1942 



— Supra-anal process without such horns; 10th abdominal 

 tergite deeply depressed and excavated behind (fig. 

 6:22c); central British Columbia to California and 

 Colorado delicatula Claassen 1923 



Key to the Females of North American Subgenera and 

 California Species of Nemoura 



t. Gills present under the neck or head 2 



— Gills absent 13 



2. One branched gill present on each side of the mentum; 

 wings not banded; 7th sternite moderately produced 

 (fig. 6:23a); Alberta and British Columbia to California 



(subgenus Visoka Ricker 1952) cataractae Neave 1933 



— Two gills present on each side of the neck, branched 

 or simple; wings usually banded, spotted, or completely 

 infuscated 3 



3. Gills simple filaments (except in cinctipes); 7th ster- 

 nite produced completely over the 8th which is very 

 weak (subgenus Zapada Ricker 1952) 4 



— Gills branched; 7th sternite moderately or little pro- 

 duced, not covering all of the 8th; 8th sternite bearing 

 a distinct terminal or subterminal notch 8 



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

 broad; southern Alaska to California, Colorado, and 

 Wyoming frigida Claassen 1923 



— Wings conspicuously banded or mostly clear; gills 

 less than 10 times as long as wide 5 



5. Gills branched 1 to several times (very rarely un- 

 branched); tip of the wing clear; Alaska to California 

 and Alberta to Colorado and Nevada; east to Manitoba 

 and South Dakota cinctipes Banks 1897 



— Gills simple 6 



6. Gills constricted at the base and one or more times 

 (usually twice) beyond the base; southern Alaska to 

 California and Utah Columbiana Claassen 1923 



'Adapted from Ricker (1952). 



