166 BULLETIN 116, UNITED STATES NATIONAL MUSEUM. 



Thorax dark shining green, sometimes with coppery reflections; 

 these may form two narrow vittae along the center of the dorsum 

 with a slender shining green line between them; the dorsimi is dis- 

 tinctly dusted with white pollen. Abdomen shining green, sometimes 

 with slight bronze reflections, and with spots of white pollen on the 

 sides of the segments. Hypopygium black; its lamellae large, some- 

 what oval in outline, white with a rather narroAV black border on the 

 ajncal margin, which is jagged and bristly, upper edge fringed with 

 black hairs, lower edge with a few pale ones. 



Fore coxae pale yellow; their anterior surface covered with abund- 

 ant silveiy white pollen and appears bare, still they have numerous, 

 very minute, white hairs, and the usual black bristles at tip. Middle 

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

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

 nearly bare below, their lower half having only very minute yellow 

 hairs. Posterior tibia a little infuscated at tip, especially on inner 

 side, where it is sometimes infuscated for one-third its length and in 

 other specimens only a little, still always distinctly blackened on 

 inner side. Fore tarsi (fig. 115a) nearly one and a half times as long 

 as their tibiae; first joint about two-thirds as long as the tibiae; 

 third and fom'th each a little more than half as long as the joint pre- 

 ceding it; first three joints slender, yellow^, last two black, compressed; 

 fourth small, somewhat triangular, about as wide at apex as long; 

 fifth wider than the fourth, somewhat oval in outline, about equal 

 to the third in length, fringed with minute recumbent hairs on upper 

 edge. Calypters, their cilia, and the halteres yellow. 



Wings (fig. 115) grayish, more or less tinged with brown in front of 

 third vein; costa scarcely at all enlarged at tip of first vein; last 

 section of fourth vem a little bent before its middle; third vein bent 

 backward a little so as to converge with fourth toward their tips; 

 hind margin of wmg a little indented at tip of fifth vein; anal angle 

 nearly obsolete, the wing being narrowed at base. 



Female. — Face wide, silvery white; third anteimal joint nearly 

 round with a notch above at tip, the arista inserted at upper corner 

 of this notch; fore tarsi infuscated almost to their base, third and 

 fifth joints of nearly equal length, fourth a little shorter, fifth a very 

 little widened; middle tibiae with three bristles below, one pair at 

 apical third and one bristle at basal third, their basitarsi with a large 

 bristle above; in the male the middle tibiae have three bristles, as in 

 the female, except that the one at basal third is small; in some 

 females the basitarsi do not have the bristle above, but it may have 

 been broken off; fore coxae less silvery than in the male and with 

 conspicuous little black hairs on their anterior surface, except on the 

 outer edge, where there are some veiy minute white ones; wings 

 about as in the male, except that the anal angle is a little more promi- 



