26 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 66 



20. ARGYRA NIGRICOXA, new species 



Male. — Length 5 mm. Face not very narrow, silvery white. Palpi 

 volrety black with black hairs. Front black with white pollen, 

 which is very thick next to the antennae. Antennae black; first 

 joint hairy above; third twice as long as wide, slightly hollowed 

 below in outline, obtusely pointed; arista as long as the antenna, 

 inserted above the point of third joint. Lateral and inferior orbital 

 cilia white, the small upper cilia black. 



Dorsum of thorax green, considerably dullc-d with white pollen; 

 scutellum with four large marginal bristles and a few small black 

 hairs on its disk; pleurae more black with abundant white pollen. 

 Abdomen Avith considerable white pollen; first segment green, a 

 little yellowish at extreme base; second and third mostly yellow 

 with the median line and narrow hind margins green; remaining 

 segments green with a narrow line of white pollen at posterior edge ; 

 all hairs and and bristles of the abdomen, even on the yellow venter, 

 black. Hypopygimn (fig. 13) and its appendages testaceous; outer 

 lamellae rather narrow, bent, blackish; inner appendages large, 

 yellowish, tipped Avith a minute bristle. 



All coxae almost wholly black; fore coxae with black hair on 

 anterior surface and black bristles at tip and on outer edge of apical 

 half. All femora yellow, posterior brown at tip and with a few 

 longer hairs on lower outer edge near the tip ; middle pair with a row 

 of long black bristles on lower posterior edge, which are a little 

 longer than the width of the femora; fore femora with abundant 

 long, black hair on the posterior surface. All tibiae yellow, pos- 

 terior pair indefinitely blackened at tip. Fore tarsi yellow, darker 

 at tip, their joints as 50-15-11-8-10 ; first joint with a row of little 

 bristles below, which are about as long as the thickness of the joint. 

 Middle tarsi infuscated from the tip of the first joint. Hind tarsi 

 wholly black, the joints as 39-33-25-12-10. Oalypters white with 

 a brown border and white cilia. Halteres pale yellow. 



Wings grayish ; third vein bent backward at tip ; fourth vein bent 

 back slightly to meet the crossvein, last section distinctly bent before 

 its middle, parallel with third beyond this bend, ending in the apex 

 of the wing; last section of fifth vein nearly straight, longer than the 

 crossvein. 



Described from one male taken at Sugar Grove, Ohio, May 19. 

 Type.— Male, Cat. No. 27045, U.S.N.M. 



21. ARGYRA CALIFORNICA, new species 



Male. — ^Length, 4 mm. Face and front silvery white, the former 

 rather narrow. Palpi and proboscis black, with black hairs. An- 

 tennae black; first joint with conspicuous hairs above; third joint 



