4 PROCEEDIlSrGS OF THE NATIOTTAL MUSEUM vol.74 



viewed from above, its suture below the middle ; palpi and proboscis 

 yellow. First two antennal joints yellow, third dark brown, about 

 as long as wide; longest bristles on second joint about half as long 

 as the antenna ; arista dorsal, scarcely as long as widtl; of head. 



Thorax and abdomen green ; dorsum of thorax with blue reflections, 

 its bristles black and rather short ; scutellum with one pair of bris- 

 tles; pleurEe covered with silvery white pollen, the posterior edge 

 mostly yellow; venter yellow, except on apical segments. Hypopy- 

 gium brown, not very large, with a pair of long slender appendages, 

 which are about as long as third joint of middle tarsi and fringed 

 with long hairs. 



All coxae yellow, middle ones largely brown on outer surface ; fore 

 coxae with small white hairs and with yellow bristles at tip ; posterior 

 coxae with one yellow bristle; all femora and tibiae wholly yellow, 

 the former almost bare below, the latter almost without bristles, 

 except a small one on middle pair; fore and middle tarsi long and 

 slender, especially the first joint, yellowish at base, but mostly 

 broAvn; hind tarsi black; middle basitarsus somewhat ciliated but 

 the hairs very short, fifth joint slightly flattened; joints of fore tarsi 

 as 145-3^20-17-7; of middle ones as 127^8-41-26-10; first four 

 joins of posterior pair as 109-42-26-12. Calypters yellow with a 

 narrow black edge and yellow cilia. Halteres yellow. Wings (fig. 

 4) grayish, long; costa ciliated with very delicate pale hairs; first 

 vein reaches about one third the length of the wing; last section of 

 fifth vein 18, cross vein forty-seven fiftieths of a millimeter long. 



FeTnale. — Very much like the male; suture of the face near the 

 middle. Tarsi nearly as slender as in the male, but shorter. 



Described from one pair taken by Nathan Banks, at Bella Vista, 

 Panama. 



Tyjje. — Male, August 8; allotype, female, July 6, 1924. Both in 

 the Museum of Comparative Zoology. 



PSILOPUS SEMICOMATUS, new species 



Male. — Length 4 mm. ; of wing the same. Face narrowed below, 

 green, the suture near apical third, lower part with coarse gray 

 pollen on the sides and along the front edge. Front blue with 

 violet reflections and long pale hair; palpi and proboscis black. 

 Antennae black, bristles on second joint one and a half times as long 

 as the antenna; third joint a little pointed at tip; arista nearly 

 apical, about as long as the abdomen. 



Thorax green with blue and violet reflections ; scutellum blue with 

 two pairs of large bristles ; bristles of thorax and abdomen large. Ab- 

 domen green with blue reflections, last two segments more coppery. 

 Hypopygium (fig. 5) brown with a long, nearly cylindrical peduncle, 

 the lamellae large, somewhat leaf -like, yellow ; there are two bristles, 



