Seit. 1894] CoQriLi.KTT. REVISION OF Famii.v Thkrkvid.k. <.)9 



Museum, five uiulescribed species were touiul, whicli, wiili Dr. 

 Riley's permission, are described herewith : 



Psilocephala limata, sp. nov. 



v — Black, tlie libicU, base of tarsi, and knob of halteres yellowish, narrow 

 hind margins of the second and third abdominal segments, while. rroiU opaque, 

 the upper half dark grayish-brown poilinose and black pilose, remainder of head 

 white poilinose, lower half of front bare; pile of cheeks, occiput and abdomen 

 (largely), white, that of the tiiora.x and scutellum mi.xed black and while, 

 scutellum bearing ^four bristles. Kirst joint of antenn;v scarcely wider than the 

 second, the third nearly twice as wide as and slightly longer than the first; style 

 one-lifth as long as the third joint. Thora.x opaque grayish-black poilinose, two 

 vitt;i: and the broad lateral margins light gray. Abdomen shining except the first 

 segment, hind margins of the second, third and fourth, nearly crossing the seg- 

 ments on the lateral margins, and nearly the whole of the fifth and si.xth segments. 

 Wings hyaline, the stigma brown; fourth posterior cell broadly open. Length, 

 12 mm. 



Colorado and Washington. Two females, from Di". Riley's 

 collection. Types in National Museum. 



In my table of species referred to above this species would 

 fall in with morata in couplet 4, e.xcepl for the much shorter 

 antennal style ; it further differs by being nearly twice as large, 

 by having the thora.x vittate, etc. 



Psilocephala placida, sp. nov. 



4.' — Dlack, the antenmv, proboscis, palpi, halteres, femora, tibia?, base of tarsi, 

 venter and abdomen excepting the tirst segment and narrow bases of the three 

 following ones, yellowish. First joint of antenna; nearly twice as wide as the 

 second, the third joint slightly wider and a trifle shorter than the first; style one- 

 third as long as the third joint. I*"ront opacjue, grayish-yellow poilinose and wholly 

 black pilose. Short depressed pile of thorax, scutellum and first four abdominal 

 segments, yellow, the longer, erect pile and bristles black; scutellum bearing four 

 bristles. Wings pale smoky-brown, center of the cells usually nearly hyaline, 

 stigma dark-brown, fourth posterior cell wide open. Length, 12 mm. 



Florida. A single female from Dr. Riley's collection, now in 

 the National Museum. 



In my table this species would fall in with slossoni .\\\(S. moniiva^^a, 

 from both of which it differs in having no black spots on the front, 

 the antenmx; yellow, etc. 



Thereva egressus, sp. nov. 



rj^— HIack, the tibia;, base of tarsi, narrow hind margins of the second, third 

 and fourth abdominal segments, and hypopygium (partly), yellowish. Head opaque, 

 gray poilinose, pile of front and sides of face black, that in middle of face, on the 

 cheeks, occiput, pleura, venter and the shorter pile of thora.x, scutellum and abdo- 

 men largely yellowish or whitish, the longer pile of abdomen, thora.v and scutellum 



