190 ERNEST A. BACK. 



rather higher than broad; face very small, narrow above, 

 broader and swollen below, in large part covered with long 

 thick hair or bristles; front small, of about equal width 

 throughout, vertex little depressed, ocellar tubercle not prom- 

 inent; eyes very high in proportion to width. Antennas ap- 

 proximate, segment 1 cylindrical, twice or nearly twice as 

 long as the second, third as long or longer than the first two 

 together, if elongate and of equal width or elongate oval, with 

 a bristle-like style; or if, as in most typical species, elongate 

 with an excision on the distal half, thus in certain positions 

 causing the segment to appear distinctly narrowed toward 

 the tip from about the middle, with a short thick distinct 

 style. Thorax moderately arched, variously clothed above 

 with hair or bristles, always with bristles on the prothorax, 

 on the lateral margins and posterior portions and scutellum; 

 hypopleura with or without pile or bristles. Abdomen 

 elongate, cylindrical, moderately bare, the male genitalia 

 proportionately small. Legs long and moderately slender, 

 hind tibiae not thickened at tip, the femora more or less 

 thickened, the underside more or less bristly, especially the 

 fore pair. Five posterior cells present, the first and fourth 

 open or closed, often varying in this respect in specimens of 

 the same species; anal cell narrowly open or closed. 



Type. — Stenopogon sahaudus Loew and Scleropogon picti- 

 cornis Loew. 



The genus Stenopogon was established in 1847. In 1866, 

 Loew established Scleropogon for the California species, picti- 

 cornis of which he had but a single specimen if I may judge 

 from the type material at the Museum of Comparative Zoology. 

 In establishing Scleropogon, he states that Scleropogons, es- 

 pecially in their markings, are like Stenopogons, but they 

 differ from them in having the face and front much narrower, 

 the third segment of the antennae shorter, the style longer, 

 the first posterior cell closed before the margin of the wing, 

 and the third extraordinarily dilated. As Mr. D. W. Coquil- 

 lett states (loc. cit.) all of these are "relative characters which 

 are seldom alike in any two species, and many of the char- 



