NATHAN BANKS. 245 



brown ; wings pale, veins brown, above and beyond tbe oblique vein, which 

 forms the X, is a brown spot, a similar spot in the hind wings, the apex of wing 

 in the vicinity of radius is clouded with brown. Prothorax once and one-half 

 broader than long, broadest behind, a median furrow and a ridge each side, 

 scarcely rugulose on sides, margin straight; a small spine at apex of tibia; wings 

 elongate, the radial sector arises quite close to the base, not forked beyond anas- 

 tomosis, the subcosta running into the oblique cross-vein, the oblique vein above 

 radius, which forms the X, is situate some distance beyond the basal cross-vein. 

 Male with a spine below before tip, genitalia extremely complex and very 

 prominent. 



Length 15 mm. 



Winnipeg, British America, June (Received from Dr. J. B. Smith). 



€AI»NITRA n. gen. 



With setae; anal space to hind wings present; veins not very 

 heavy; space beyond discal cell long; discal cell giving off two 

 sectors; second tarsal joint short; anterior coxae well separated. 

 The space between the radius and radial sector beyond the anasto- 

 mosis is traversed by two or three irregular cross-veins; no such 

 arrangement exists in any of the allied genera. 



< apnura venosa n. sp. 



Black; wings infuscate, veins black; tibia slightly paler than the rest of leg; 

 vertex with a small median depression above the ocelli ; antenna? about one-half 

 the length of the body, basal joint rather large but short; wings slender, fully 

 twice as long as the abdomen, median space with but one transverse veinlet: 

 setas with about fifteen joints. 



Length 9-10 mm. 



Pullman, Washington, April (R. W. Doaue). 



EPHEMERIDJE. 



The classification of the may-flies has long been extremely diffi- 

 cult, and there is no prospect that it will ever be very easy. The 

 groups of Cwnis and Bcetis are undoubtedly very distinct ; the 

 former is probably related to Polymitarcys. This latter genus, by 

 the number of veins between veins 8 and 9,* differs greatly from all 

 others; it appears to be one of the most primitive genera, The 

 genus Baitisca is peculiar among all may-flies by the course of veins 

 9 and 9 l , therefore, I think, merits to stand alone. Blasturus falls 

 as a synonym of Leptophlebia, as the slight difference between the 



* I use 8 for the anal, and 9 for the 1st axillary, 9" for second axillary, and 6 

 for the prsebranchial, exactly as given by Eaton. 



TRANS. AM. ENT. SOC. XXVI. MAY, 1900 



