April, 1911.] New Species of Diptera of the Genus Erax. 309 



die and directed outward, hypopygium much narrower than in 

 stramineus, clothed with black and white hair, and distinctly 

 notched at the apex. 



Female abdomen uniformly yellowish pollenose and clothed 

 with pale hairs, ovipositor about four millimeters in length, 

 equivalent to the last three abdominal segments. 



Specimens of both sexes taken in Clark County, Kansas, by 

 Dr. F. H. Snow. 



As has been stated the species has much the appearance of 

 rapax, but the somewhat stouter form, the white mystax and 

 beard and much slenderer hypopygium designate it as wholly 

 distinct from that species. 



Erax truncatus n. sp. Thorax yellowish-brown, above, abdo- 

 men gray, first four segments with long white hair, legs black 

 with the exception of the basal part of each tibia which is light 

 reddish. Total length 22 to 30 millimeters. 



Alystax and beard white, occllar, occipito-orbital and a trans- 

 verse row of bristles on the dorsum of the prothorax black, palpi 

 black with black and white hairs intermixed, dorsum of the 

 thorax, and the scutellum with many black hairs and bristles but 

 there are some white ones intermixed, wings hyaline. 



First segment of the male abdomen with long white hairs on 

 each side, second, third and fourth segments with long silvery 

 hair parted at the middle and directed outward, fifth, sixth and 

 seventh segments silvery white pollenose but without long hair; 

 hypopygium rather large, from dorsal view about as wide as the 

 last segment of the abdomen, from side view most prominent 

 near middle above and cut off at tip so as to give a truncate 

 appearance. 



First seven segments of the female abdomen silvery white, 

 ovipositor slender, shining black, about seven millimeters in 

 length. 



Several specimens from the Huachuca Motmtains, Arizona, 

 July 28, 1907. 



The large compact hypopygium of the male and the long ovi- 

 positor of the female give this species a distinct appearance which 

 makes its separation from others easy. 



Erax pallidulus n. sp. A pale colored species with black legs 

 and hyaline wings. The male has the hypopygium small and, 

 from dorsal view, very narrow. Total length, 18 to 28 millimeters. 



Alystax very pale yellowish, beard white, palpi black with 

 white hair, occipito-orbital and ocellar bristles mostly black; 

 thorax dorsally pale yellowish gray with short black hair anteri- 

 orly and black and white bristles and hairs posteriorly, scutellum 

 with pale hairs and bristles, legs black, except bases of tibiae 

 which are pale, wings hyaline. 



