228 BULLETIN 116, UNITED STATES NATIONAL MUSEUM. 



reflections; its lamellae moderately large, somewhat subquadrate, 

 but rounded at tip, nearly one and a half times as long as wide, yel- 

 lowish white, with an apical black border, which is jagged and bristly, 

 fringed above with hairs which are black on outer portion, white at 

 base. 



Fore coxae yellow with a green stripe on outer posterior edge, 

 anterior surface clothed with delicate little white hairs; there are only 

 a few little black hairs at extreme base of inner edge. Middle and 

 hind coxae black with yellow tips. Femora and tibiae yellow. 

 Middle and hind femora each with one preapical bristle, the latter 

 nearly glabrous below. Posterior tibiae slightly thickened, usually 

 blackish at tip for nearly one-fifth their length; the glabrous stripe on 

 upper surface distinct and another glabrous line just inside of the 

 inner row of large bristles. Middle tibiae with a row of three large 

 bristles below, their basitarsi without a bristle above. Fore tarsi 

 scarcely longer than their tibiae, black from' the tip of the first joint, 

 which is about as long as the three following joints together; fourth 

 and fifth joints of about equal length. Middle tarsi a little shorter 

 than their tibiae, black from the tip of the joint. Hind tarsi about 

 one and a fourth times as long as their tibiae, deep black from the 

 tip of the first joint, first joint yellow at base for about half its length, 

 the black not sharply limited. Calypters and hal teres yellow, the 

 former with very long, dense, deep black cilia. 



Wings (fig. 165) grayish, usually darker in front of third vein; costa 

 scarcely enlarged at tip of fifth vein, still when viewed from in front 

 there is a cylindrical thickening which begins before the tip of fifth 

 vein and ends abruptly a short distance beyond the tip; it is not con- 

 spicuous; last section of fourth vein bent before the middle; third 

 vein bent backward at tip; hind margin of wing indented at tip of 

 fifth vein; anal angle prominent but rounded; costa and veins yel- 

 lowish brown, the thickening of the costa blackish. 



Female.— Face a little wider, shorter and more gray than in the 

 male; antennae a little smaller; pollen of the dorsum of the thorax 

 more gray; costa not at all enlarged at tip of first vein; cilia of the 

 calypteres about as in the male. 



Redescribed from about 25 specimens. J. M. Aldrich took it at 

 Wells, Nevada, July 12, 1911; and in South Dakota. E. P. Van 

 Duzee took it at San Diego, California, October 18, 1913. A. L. Melan- 

 der took it at Yellowstone Park, Upper Geyser Basin, August 7, 

 1918; Moscow Mountain, Idaho, September 16, 1917; and at Gar- 

 diner, Montana, August 17, 1918. 



Type. — In collection of J. M. Aldrich, from Custer, South Dakota. 



