280 ERNEST A. BACK. 



of the posterior tarsi comparatively long, otherwise short, all the bris- 

 tles on the legs are black. Halteres blackish-brown. Proximal half of 

 wings hyaline; distal half blackish-gray; venation normal; veins black. 



Type.—M. C. Z. 



Habitat. — San Francisco, Cal. (H. Edwards). 



Osten Sacken states that he has three males 4-10 mm. 

 long, from San Rafael, Marin Co., Cal., May 31, which agree 

 perfectly with Loew's description except that the grayish 

 pruinose cross-bands on segments 2-4 have a distinct black 

 emargination in the middle, which Loew does not mention. 

 The third antennal segment is sometimes reddish; the anten- 

 nal style is long though, longer than half of the third segment. 

 The thorax of Osten Sacken's specimens show, on each side 

 of the median stripe, anteriorly, a short streak of whitish 

 bloom. 



Osten Sacken gives the following description of three fe- 

 males taken on the same day with the males, and a fourth 

 taken at the end of April in Sonoma County. 



" 9 . — The cross-bands of whitish bloom on segments 2-4 are nearly 

 parallel, slightly narrower in the middle, especially on the fourth seg- 

 ment, where they are more expanded on the sides; on the fifth segment, 

 the cross-band is interrupted in the middle. The pile on the sides of 

 the abdomen is white, with the exception of a tuft at the base of the 

 first segment on the sides and of a smaller one on the sides of the second 

 segment. The prevailing pubescence on the tarsi is black; the white 

 hairs on the posterior tarsi, which are conspicuous in the males, are 

 wanting here. The brownish on the distal part of the wings is much 

 less distinct than in the male, hardly perceptible. The antennae of 

 one of the specimens are somewhat reddish toward the end. Length 

 10-12 mm." 



There is one male and one female at the Massachusetts 

 Agricultural College from Vernon, B. C, captured in May 

 14r-22, which agree with the above description. 



Cyrtopouon nioiitauiis. 



Cyrtopogon montanus Loew, Berl. Ent. Zeit., 1874, 362. 

 Cyrtopogon m,ontanus Osten Sacken, West. Dipt., 298, 1877. 

 % 9- — Length 8-11 mm. — Deep black; hind tibiae, except at base 

 and tip, and the tarsi, in varying degree, reddish; pile chiefly black; 

 segments 2-5 of abdomen each with a posterior white pruinose fascia; 

 wings grayish hyaline. 



-J, . — Deep black; hind tibiae dark reddish, brownish-black at base 

 and tip; all the tarsi dark reddish, the fore pair moderately slender. 



