AMERICAN DIPTERA. 269 



male, but the sexual ornaments on the front and middle tarsi are 

 wanting. Wings with the grayish tinge a little more saturate than 

 in the male." 



Type. — M. C. Z. One male specimen in Loew's collection. 

 There are, however, three males, three females, and a pair in 

 coitu in Osten Sacken's collection Osten Sacken states that 

 his above description was made from eight males and seven 

 females, but they are not all at the M. C. Z. Neither is the 

 female type from which Loew made his detailed but unrecog- 

 nizable description. There is one male homotype at the 

 Massachusetts Agricultural College. 



Habitat. — Yosemite Valley (June 5-12), Summit Station, 

 Sierra Nevada (July 17), and Webber Lake, Sierra Co. (July 

 22-26), Cal.— Osten Sacken: Southern Wyo. (alt. 8,000 ft.); 

 Hudsonian Zone, N. M.; Sisco, Cal. (alt. 6,000, from G. 

 Franck) . 



A very pretty species. Easily and quickly recognized by 

 the sharp contrast between the long fine white pile of the 

 first and second abdominal segments and the black pile of the 

 following segments, and by the parted silvery pile of the front 

 tarsi and the broader than high brush of the middle tarsi. In 

 the female too much stress cannot he laid upon the density 

 of the thoracic bloom and the definitiveness of the two nar- 

 row dark stripes on the dorsum. 



Cyrtopogou cyiubalista. 



Cyrtopogon cymbalista Osten Sacken, West. Dipt., 297, 1877. 

 % ^. — Length 11-13 mm. — -" %. — Length 11-12 mm. — Like calliped- 

 ilus in the ornamentation of the four anterior tarsi and in the general 

 coloring of the body, but with the following differences: — The abdo- 

 men is uniformly clothed with black pile. The white pile on the lower 

 part of the occiput and on the thorax and front coxas is less long and 

 conspicuous. The black pile on the upper part of the occiput reaches 

 TTiuch lower here. Only the four anterior femora have some white 

 pile on their posterior side. The brownish bloom on the thorax is 

 hardly perceptible here. The front tibiae and the tips of the four 

 hind tibiae are black. Besides the silvery hair on segments 2-5 of the 

 front tarsi, some silvery pile is also perceptible on the first segment. 

 The under side of the same tarsal segment is not beset with dense 

 brushes of short black bristles as it is in callipedilus, so that the white 

 silvery hairs are visible from below, which they are not in the other 



TRAXS. .^M. ENT. SOC., XXXV. ' JULY, 1909 



