286 ERNEST A. BACK. 



seventh segment, in the female, is black, polished; the hypopygium 

 of the male is also free of bloom, but beset with yellowish-white pile. 

 Tips black, beset with long, white pile; bristles on the tibiae also white, 

 except the terminal ones and those on the front side of the front pair. 

 Halteres with a lemon-yellow knob. Wings hyaline, veins black, 

 normal. 



Type. — M. C. Z. Five male and one female specimens in 

 excellent condition. 



Habitat. — Webber Lake, Sierra Co., Cal. (July 22, Osten 

 Sacken) . 



The antennal style is comparatively shorter in all the pre- 

 ceding species (positivus and sudator), somewhat coalescent 

 with the third segment; the bristles at tip are very distinct. 



Cyrtopogon profusus. 



Crytopogon profusus Osten Sacken, West. Dipt., 305, 1877. 

 Cyrtopogon profusus Wiiliston, Trans. Amer. Ent. Soc, XI, 13 

 (locality reference). 

 " % 9- — Length, tf 11-12 mm.; 9 12-13 mm. — Thorax, including 

 its sides and corners and scutellum, densely clothed with gray pollen; 

 three brown stripes on the dorsum; the intermediate one geminate, 

 reaching from the anterior border to the scutellum (where it becomes 

 almost black), longitudinally bisected by a gray line; the lateral stripes 

 broad, abbreviated anteriorly and bisected transversely by a gray line 

 along the thoracic suture; the two halves thus produced are about 

 equal in size, the anterior one being nearly round; both are dark 

 brown on their inner side; the hair on the dorsum is black; a fringe 

 of black hairs along the edge of the scutellum. Abdomen black, pol- 

 ished; posterior margins of segments 1-5 with a moderately broad 

 cross-band of white bloom, in the male the segments preceding the 

 hypopygium are also whitish pruinose; the sides of the abdomen on 

 the basal half have tufts of long, soft, white hair; the fan-like fringe 

 of hairs on the pleurae in front of the halteres is white. Hypopygium 

 beset with some black pile. Face and front brownish-gray, beset with 

 black pile; in the female I perceive some white hairs mixed with the 

 black ones in the mystax. Antennae black. Legs brownish-red; fe- 

 mora with black stripes along the upper side; they are beset with long, 

 soft, white hairs; tibiae with short, white pile and black bristles, a few 

 of the bristles on the middle and hind tibiae are pale yellow; tarsi 

 reddish-brown, almost black on the upper side; claws whitish, with 

 black tips; pulvilli whitish. Wings grayish hyaline; venation normal. 



Type. — M. C. Z. One male and three female specimens. 

 Habitat. — Morino Valley, N. M.; Sangre de Cristo Mts., Col.; 

 Kans. (F. H. Snow). 



