214 THOMAS SAY FOUNDATION 



long, narrowed behind ; angles widely rounded. Wings 

 uniformly subhyaline ; anal field of hind wings large. Gills 

 apparently absent. 



Male. Subanal lobes wide, entire, with hind margin 

 broadly bilobed ; cerci greatly modified into accessory cop- 

 ulatory organs, the outer half heavily chitinized and 

 terminating in three spines, the inner portion mem- 

 branous ; supra-anal process recurved, much enlarged, 

 largely membranous, and below, armed with small spines; 

 subgenital plate short; ventral lobe broad, truncate, 

 about one-half times as long as wide. 



Female. Seventh sternite produced into a broadly 

 rounded subgenital plate which covers most of segment 

 eight ; eighth sternite unmodified. 



Holotype, male, allotype, female, June 17-20, 1904, Mud 

 Creek, Tompkins Co., N. Y., Cornell University Collection. 



One male, Murray Bay, Province of Quebec, July or 

 August, 1878 (E. Corning, Jr.) ; June 2, 1923, McLean, 

 Tompkins Co., N. Y. 



Nemoura similis Hagen. 



(Plate 37, fig. 16.) 

 1861. Taeniopteryx similis Hagen, Syn. Neur. N. A., p. 34. 

 3 907. Nemoura similis Banks, Cat. Neur., p. 14. 



Length to tip of wings, female, 8.5 mm. Expanse, fe- 

 male, 16 mm. 



General color black. 



Head shiny black, wider than prothorax; hind ocelli 

 about twice as close to eyes as to each other. 



Prothorax black, very rugose; considerably widened 

 posteriorly, wider than long; front angles very broadly 

 rounded, hind angles narrowly rounded. Wings with 

 three transverse dark bands, one at the apex, one across 

 the cord and a wide band at the base. 



Abdomen dark brown. Gills apparently absent. 



Female. Seventh sternite unmodified ; eighth sternite 

 somewhat produced, with a shallow median notch. 



Male unknown. 



Type, female, No. 252, May, Washington, D. C. (Osten 

 Sacken, in Hagen Collection, Mus. Comp. Zool., Cam- 

 bridge, Mass.). 



We have not been able to find any males which can be 

 definitely placed with this female. 



