AMERICAN DIPTERA. 271 



fore not parted in the middle; in callipedilus and cymbalista the silvery 

 hairs are found both on the outer and inner side of the upper part of 

 the tarsi, and are parted in the middle; some silvery pile on the outside 

 of the first segment; the last two segments of the tarsi with a disk- 

 shaped, flat brush of black bristles, as in callipedilus and cymbalista; 

 pul villi blackish-brown; all the femora and the four posterior tibiae 

 beset with long pale yellowish pile. Wings grayish hyaline. 



9 . — Like the male, except in the sexual ornamentation of the front 

 and middle tarsi, etc. Abdomen black, polished, the sides densely 

 beset with pale yellowish-white pile, through which, on segments 2-5, 

 the white pruinose spots in the hind corners of the segments are 

 visible. Will be easily distinguished from C. callipedilus female by its 

 pruinose scutellum, less densely pruinose thoracic dorsum, more yel- 

 lowish pile of the face and thorax, etc." 



Type. — M. C. Z. Four male and two female specimens. 



Habitat. — Morino Valley, N. M. (July 1); Spanish Peakes, 

 Col. (June); Sioux Co., Nebr. ; Cache Valley, Utah; divide be- 

 tween Idaho and Montana. 



I have referred a male specimen from Gallatin Valley, Mont. 

 (July 6, R. A. Cooley), to this species. 



Cyrtopogon prsepes. 



Cyrtopogon p rapes Williston, Tr. Am. Ent. Soc, XI, 12, 1884. 



" % 2. — Length 11-12 mm. — Scutellum convex above, pilose; legs 

 densely pilose, wholly black; front tarsi of the male with a single row 

 of silvery pile from the very base, and the terminal segments of the 

 middle tarsi with a disk of black pile, longer than broad; sides of the 

 abdomen at base white pilose, shorter and black on distal portion. 



Black, polished. Face thickly yellowish pruinose, but concealed 

 beneath the dense light yellow mystax, black on the oral margin. 

 Beard, anterior and middle coxae, first two segments of the abdomen 

 on the sides, and all the femora below, and on the posterior part, 

 thickly, nearly white pilose; front, upper part of the occiput, basal 

 segments of the antennas, dorsum and scutellum, tergum and sides 

 from the second segment, upper surface of femora and all the tibiae 

 black pilose. Dorsum with two large spots on each side of the middle 

 in front, brownish pruinose; pleurae thickly light pruinose. Legs wholly 

 deep black, the posterior tibiae at tip and their metatarsi with golden- 

 red pubescence. Legs not very stout nor the bristles very strong; 

 front tarsi slender, on their upper side for their whole length with a 

 row of short, dense, silvery pile, not parted, except at the tip, the 

 surface below is smooth, but along the sides there is a fringe of very 

 short black bristles; last two segments of middle tarsi with the disk 

 of black pile narrower than in the other species, longer than broad. 

 Wings nearly hyaline. 



TRANS. AM. ENT. SOC., XXXV. JULY, 1909 



