14 PROCEEDINGS OF THE NATIONAL MUSEUM vol. GO 



This species is remarkable for the conspicuous hair on the disk of 

 the scutelhim, the long, bristle-like hair on the coxae and femora, 

 and the large, lamellu-like inner appendages of the hj'popygium of 

 the male. 



Type and allotype.— M.^\q and female. Cat. No. 27038, U.S.N.M. 



8. ARGYRA NIGRIVENTRIS, new species 



Ty2)e and allotype.— Male and female, Cat. No. 27038, U.S.N.M. 

 former moderately wide. Palpi and proboscis black, with black 

 hairs. Antennae black; first joint with about four hairs above; third 

 joint a little longer than the two first taken together, pointed at tip ; 

 arista inserted a little before the tip, about as long as the antenna. 

 Lower orbital cilia white; the minute black upper cilia descend to 

 the middle of the eye. 



Dorsum of thorax dark shining green, or blue green, covered with 

 quite abundant silvery white pollen, especially on the anterior half; 

 pleurae more black with white pollen; scutellum with two pair of 

 large marginal bristles. Abdomen black; all but the first segment 

 covered Avith thick silvery white pollen; first segment and sides 

 of the others with green reflections; hairs and bristles on the ab- 

 domen black, those on the last two segments appear reddish in certain 

 lights. Hypopygium (fig. 11) black, small; its outer lamellae black, 

 somewhat triangular, fringed with reddish hairs; the inner appenda- 

 ges are a central yellow organ, a pair of lamella-like organs with 

 several hairs, and a pair of rather slender organs tipped with a 

 minute bristle. 



All coxae black, with black hairs and bristles; anterior pair with 

 a row of long slender bristles besides those at tip; these are longer 

 than the thickness of the coxa. Fore femora black with yellowish 

 tips; they have moderately abundant, long, black hair on posterior 

 surface. Middle femora with long hairs on the lower surface, not as 

 long as the width of the femora. Fore and middle tibiae and basi- 

 ta'rsi yellow ; joints of fore tarsi as 38-10-8-5-6. Posterior femora, 

 tibiae, and tarsi wholly black; lower surface of hind tibiae clothed 

 with long, delicate hairs, which are *about as long as the small 

 bristles on upper surface ; these hairs are black but appear reddish in 

 certain lights; joints of hind tarsi as 59-18-15-7-8. Hind basitarsus 

 a little thickened at base, fringed on each side of lower surface with 

 long bristly hairs, the longest of which near the base are longer than 

 the second joint and appear reddish in certain lights. Calypters 

 dark yellow with black tips, their cilia black or reddish. Knobs of 

 halteres yellow, stems brown. 



Wings gi-ayish, slightly tinged with brown in front of third vein ; 

 third vein bent backward a litle at tip; last section of fourth vein 



