184 BULLETIN 116, UNITED STATES NATIONAL MUSEUM. 



base, nearly twice as long as wide, ovate but a little pointed at tip. 

 Palpi yellow. Lateral and inferior orbital cilia yellow, a few of the 

 upper cilia black. 



Thorax green, sometimes with coppery or bronze reflections; 

 pleurae dulled with white pollen. Abdomen green with white 

 pollen on its sides. Hypopygium black with green reflections; its 

 lamellae rather small, somewhat oval in outline, whitish, sometimes 

 almost brown, with a narrow black margin, which is broadest at 

 the apex and extends along both edges in some specimens, in others 

 only along the upper edge, jagged and bristly on apical margin, 

 especially at the lower corner, fringed above with little brown haii-s. 

 Fore coxae yellow with little black hairs on the anterior surface. 

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

 yellow. Middle and hind femora each with one preapical bristle, 

 the latter without cilia below. Middle tibiae a little longer than 

 their femora, compressed, very slender except at base and tip, where 

 they are nearly normal in size; usually with a blackish line on upper 

 edge and when viewed from the side there often appears to be a 

 median brown line extending nearly their whole length; their anterior 

 side is covered with silvery pollen, and near the tip is a whitish ring, 

 which sometimes only shows as a whitish spot on the front surface; 

 extreme tips black. Posterior tibiae a little thickened, black at 

 tip for a short distance; inside of the inner row of large bristles is a 

 slender glabrous line extending nearly their whole length. Fore 

 tarsi about one and a fourth times as long as their tibiae, infuscated 

 from the tip of the first joint, which is about as long as the three 

 following joints taken together. Middle tarsi (fig. 12Sa) black, 

 about three fourths as long as their tibiae, the fu-st joint about as 

 long as the two following joints taken together, a little thickened, 

 fringed on both sides with black hairs which give it a broad, some- 

 what elongate-oval form. Hind tarsi whoUy black, a little longer 

 than their tibiae. Calypters and halteres yellow, the former with 

 black cilia. 



Wings (fig. 128) grayish, sometimes tinged with brown; costa 

 with a small knotlike enlargment at tip of first vein; last section 

 of fourth vein bent before its middle; hind margin of wing scarcely 

 indented at tip of fifth vein, beyond which is a slight sinus that 

 leaves a broad lobe at tip of sixth vein, the anal angle being very 

 prominent. 



Female.— Face wider, shorter and more gray than in the male; 

 middle tibiae normal, their tips slightly enlarged, sometimes more 

 conspicuously black than in the male, at others nearly yeUow; middle 

 tarsi normal, wholly black, about as long as their tibiae, first joint 

 without a bristle above, their tibiae with one large bristle below: 



