PLECOPTERA OF NORTH AMERICA 203 



Nemoura divergens Claassen. 



(Plate 34, figs. 8-10.) 

 1923. Nemoura divergens Claassen, Can. Ent., 55:282. 



Male. Length to tip of wings, 8.5 mm ; expanse, 15 mm. 



General color brown. Head not wider than prothorax, 

 brown, occiput quite rugulose; hind ocelli a little closer 

 to eyes than to each other. Prothorax brown, wider than 

 long, widened behind, angles broadly rounded. Legs light 

 brown. Wings subhyaline with a darker band across the 

 cord and somewhat darker at the tip; anal field of hind 

 wings large. 



Subanal lobes unmodified ; subgenital plate quite short ; 

 cerci largely membranous ; ventral lobe about twice as 

 long as wide; supra-anal process recurved, smooth, en- 

 tirely chitinized; each side of the supra-anal process a 

 long, slender, chitinized divergent process. 



Female, unknown. 



Holotype, male, Mar. 15, Clinton, N. Y. (P. B. Powell, in 

 Cornell University Collection) ; one male, Apr. 17, Ithaca. 

 N. Y. ; one male, Mar. 30, Forest Hills, Mass. 



Nemoura columbiana Claassen. 



(Plate 34, figs. 11, 12, 13.) 

 1923. Nemoura columbiana Claassen, Can. Ent., 55:286. 



Male. Length to tip of wings, 6.5 mm. ; expanse, 11 mm. 



General color dark brown, with banded wings and legs. 



Head wider than prothorax, blackish brown ; hind ocelli 

 closer to eyes than to each other. Prothorax blackish 

 brown, slightly rugose, wider than long, narrowed be- 

 hind; front angles broadly rounded; hind angles almost 

 sharp; sides straight. Legs brown with a light spot or 

 band just beyond the middle on femora. Wings subhy- 

 aline, with two dark transverse bands, one at the cord 

 and the other before the tip; anal field of hind wings 

 large. Four single gills present in the cervical region. 



Subanal lobes large, curved upward and bearing on the 

 inner margin (ventral view) a curved spine-like process ; 

 below (side view) a short triangular process; cerci small, 

 membranous; supra-anal process recurved, short, en- 

 larged, partly membranous ; subgenital plate quite short ; 

 ventral lobe truncate, a little more than twice as long as 

 wide. 



Female, unknown. 



Holotype, male, June 25, 1908, between Laggan and the 

 valley of the Ten Peaks, Alberta, Canada (J. C. Bradley, 

 Cornell University Collection). 



