snow: DIPTERA of COLORADO AND NEW MEXICO. 23 1 



merits; fifth segment and hypopygium shining black or bronze black. 

 Legs (the hind pair are missing) yellow; the immediate base of the 

 femora and the tarsal joints infuscated. Halteres of the same color 

 as the legs. Wings hyaline, stigma yellowish. — Length 7 mm. 



One specimen, Windy Gulch, Front Range, near Estes Park, Colo., 

 (Prof. V. L. Kellogg, June 25, 11,000 ft.). 



Distinct in its pinched face, narrow prominent tubercle, and large 

 and prominent frontal triangle. 



Platychirus peltatus Meig:. 



A single specimen, from Green Mountain Falls, Colo. (July). A 

 northern species, hitherto recorded from northern Europe, Alaska 

 and the mountains of New England. 



Platychirus chaetopodus AVill. 



One male specimen, Colorado (Gillette, No. 1709), agrees well with 

 the description. The very insignificant facial tubercle scarcely shines 

 through the covering of yellowish pollen; the outer angle of the distal 

 end of the flattened front tibiee is sublappet-like, though by no means 

 as strongly produced as in P. qtiadrattts. The species was described 

 from Washington (state). 



Platychirus hyperboreus St;pg. 



One male specimen, Colorado (Gillette, No. 1709), is best placed 

 here. The face is thinly pollinose, and the outer corner of the distal 

 end of the front tibise is more produced than in Williston's figure 

 (Synopsis, pi. Ill, fig. 12). The abdominal spots are smaller than in 

 quadratus and the fifth segment is wholly black. A northern and 

 mountain species. 



Platychirus palmulosus, n. sp. 



Male. Shining metallic greenish black. Face shining black with 

 a very thin covering of grayish pollen and sparse light pile; tubercle 

 rather prominent, much more so than in the two preceding species; 

 frontal triangle more metallic greenish with yellowish pile and pollen. 

 Antennae dark brown, first joint darker. First segment of abdomen 

 and hypopygium brassy greenish black; fifth segment wholly obscure, 

 reddish; the reddish s|:)ots of second and third segments leave uuly very 

 narrow or subobsolete hind borders and median stripes; black hind 

 border of second segment also very narrow and the median stripe 

 widened anteriorly where it reaches the lateral margins. Legs reddish 

 yellow, hind femora and tibi-se with brown spots near the middle; 

 hind metatarsi except the tip, black; last two hind tarsal joints brown; 

 front tibise whitish digtally, the outer angle of their distal end strongly 



