OSTEN SACKEN ON WESTERN DIPTERA. 315 



ing a stump-, or thumb-like appendage ; middle tarsi blackish, except at 

 the base 5 hind femora with a few black bristles on the latter half of 

 the under side, forming an incipient fringe • hind tibia* broadly black at 

 the tip, glabrous on the inside; hind tarsi altogether black. Wings 

 with a slight swelling of the costa at the eud of the first vein ; fourth 

 vein bent bnt not broken. Length 5-6 mm . 



Hah —Webber Lake, Sierra Nevada, California, July 24. Three males. 



3. Doltchopus canaliculate (syn. JDolichopus canaliculatus Thom- 

 son, Eugenies Resa, 512.)— Male.— Bright metallic-green, with a slight 

 yellowish pollen on the thorax. Face silvery, somewhat yellowish above ; 

 antennae red ; third joint brown, except the under side at the base ; cilia 

 of the tegulaa black; lamellae of the hypopygium unusually long, whitish, 

 foliaceous, narrow at base, margined with brown ; the large emargination 

 at the end has a smooth edge, not jagged, and beset with a few almost 

 imperceptible hairs ; a smaller emargination alongside of the large one 

 is beset with curved bristles, which extend along the inuer edge of the 

 lamella and are much less coarse than in other species. Legs, includ- 

 ing front coxae, pale yellow ; front tarsi about once and three-fourths 

 the length of the tibia : three first joints slender, stalk like, nearly of 

 j equal length; the fourth very minute, subtriangular, white ; the fifth 

 lamelliform, black ; four posterior tarsi brownish, except at base; hind 

 femora on the inuer side with a fringe of long yellowish hairs; hind 

 tibiae on the inside before the middle with a glabrous spot of a brown- 

 ish-yellow, which sends out a glabrous line, running along the upper 

 side of the tibia to very near its tip. Wings subhyaline ; third vein 

 bent but not broken. Length about o mm . 



Rab.— San Rafael, Oal., May 14 and 27. Two males. I also have a 

 female from Brooklyn, near Sau Francisco, July 11, apparently belonging 

 here. The hairs on the. hind femora of the male being on the inner side*, 

 and not along the lower edge, are somewhat difficult to perceive. 



There can be but little doubt about the synonymy, although I do not 

 quite understand the description of the hind tarsi; at any rate, the 

 (word " postici » is inadvertently omitted in that description. * 



Tachytrechus. 



Of the two Californian species which I possess, the one is identical 

 with a species from the Atlantic States, the other closely resembles an- 

 other species from the same region. 



I 1. Tachytrechus angustipennis (syn. Tachytrechus angustipennis 

 Loew, Monogr., etc. ii, 113, 3).— The specimens, males only, de- 

 scribed by Mr. Loew, were from the District of Columbia. I have 

 (four males and one female from Los Guilucos, Sonoma County, July 

 6, and a single female from Summit Station, Central Pacific Railroad, 

 ^n the Sierra Nevada, at 7,000 feet altitude. I hardly doubt of the 

 specific identity. The only discrepancy from Mr. Loew's description 

 is that the brown lines on the thorax are not " very much shortened" 

 l 9 H B 



