78 BULLETIN 116, UNITED STATES NATIONAL MUSEUM. 



38a) wholly black: third joint one and a half times as long as wide, 

 somewhat pointed at tip. 



Thorax green, sliining, sometimes with blue and coppery reflec- 

 tions, which form narrow stripes on the dorsum; pleurae dulled with 

 gray pollen. Abdomen green with blue and coppery reflections and 

 black incisures; second segment with a patch of rather long yellowish 

 white hair on each side near the lower edge, usually this hair is quite 

 conspicuous. Ilypopygium black; its lamellae (fig. 38) rather small, 

 somewhat circular in outline but nearly straight above, blackish, not 

 jagged, fringed with delicate black hairs. 



Coxae black with yellow tips; anterior pair with white pollen and 

 black hairs on the front surface, fore and middle femora black with 

 yellow tips; middle pair black with apical third or more yellow, the 

 black shading into the yellow. Hind femora nearly bare below with 

 rather long hair on upper edge and two preapical bristles, one nearly 

 below the other; middle femora with two, often with three preapical 

 bristles. Tibiae yellow; posterior tibiae black at tip, the black shad- 

 ing into the yellow and extending to or beyond the middle on inner 

 side, a little stouter than the others, slightly swollen at basal third 

 and at tip; the glabrous stripe on upper surface wide, extending 

 upon the inner side of the inner row of large bristles for about one- 

 third their length. Fore tarsi nearly equal to their tibiae in length; 

 first joint scarcely as long as the remaining four taken together, 

 brown from the tip of the first joint. Middle tarsi one and a fourth 

 times as long as their tibiae, black from the tip of the first joint. 

 Hind tarsi deep black, one and a third times as long as their tibiae. 

 Calypters and halteres yellow, the former with black cilia. 



Wings grayish, a little darker along the front; costa scarcely en- 

 larged at tip of first vein; last section of fourth vein a little bent 

 near its basal third; hind margin of wing scarcely indented at tip of 

 fifth vein, not much rounded, the wing being of nearly equal width; 

 anal angle rounded, not very prominent. 



Female. — A number of females were taken with these which differ 

 from the males in having all the femora black with the tips yellow; 

 middle tibiae yellowish at base becoming black at tip, sometimes 

 largely black; the tarsi all black, except the fore basitarsi, which are 

 mostly yellow. The wings are more broadly rounded on the hind 

 margin than in the male. The middle and hind femora each with 

 two preapical bristles which are placed one nearly below the other; 

 middle tibiae with two bristles below, their basitarsi with a large 

 bristle above. 



Described from 8 males and 12 females which were taken on 

 Craig's Mountain, Idaho, and 1 male taken at Lawyer's Canyon, 

 Idaho, June 16, 1909 (all by J. M. Aldrich). 



