262 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.46. 



extend well beyond apex of triangle; triangle shiny black, obscured 

 by grayish pollen; face and cheeks yellow, the latter blackened on 

 posterior margin, occupit black; antennae black; palpi yellow; 

 proboscis brown-black; upper mouth margin black. Abdomen 

 yellowish ventrally, and on apices of abdominal segments. Legs 

 yellow, blackened on upper surface of fore femora, apices of mid 

 and hind femora, and whole of tibiae and tarsi, except bases. Wmgs 

 slightly browned, veins dark brown. Halteres yellow, all hairs 

 and bristles on body and legs black. 



Slender. Frons occupying one-half the width of head, the sides 

 slightly divergent posteriorly; triangle equilateral, extending well 

 toward eye margin at vertex and two-thirds of the length to anterior 

 margin of frons; no hairs on margins of triangle, those on lateral 

 margins of frons strong, the two on lower half bristlelike and point- 

 ing out over eye, the surface haks absent on the pale center, except 

 in front; antennae above average size, third joint rounded, pubes- 

 cent; arista swollen, and tapering, at base, as long as width of frons, 

 pubescent; cheek slightly produced anteriorly, in height equal to 

 about one-half the width of third antennal joint, marginal hairs 

 distinct, the anterior one setulose; proboscis thick, apical portion 

 bent back for a short distance; palpi normal. Mesonotum without 

 punctures, the hairs short, in the lateral two rows single, in the center 

 row double; pleurae concolorous with disk of mesonotum; scutellum 

 with posterior margin rounded, apical pan- of bristles long, not 

 closely approximated nor cruciate, besides these two long bristles 

 there are two shorter marginal bristles and a few discal hahs. Legs 

 rather slender, and elongated; hind tibial spur situated at apex 

 and about equal in length to tibial diameter. Wings narrow, third 

 costal division equal to two-thirds the length of second; third and 

 fourth veins gradually, but slightly divergent; outer cross vein 

 upright, last portion of fourth vem twice as long as penultimate 

 portion; last portion of fifth vein three-fifths as long as penultimate 

 portion of fourth. 



Length, 2-3 mm. -. 



Redescribed from type-specimen. Locality, Algonquin, Illinois. 



Other specimens m collection as follows: One from Bascayne Bay, 

 Florida; one with No. 265, no other data; and one from Frontera, 

 Tabasco, Mexico, March 26, "light" (C. H. T. Townsend). The 

 Mexican specimen is the smallest of the lot and rather immature, 

 but I have not the least doubt as to its identity. 



PSEUDOHIPPELATES GRACILIS, new species. 



Figs. 26-28. 



Female. — Black, shining. Frons black, opaque; anterior margin 

 broadly yellow, the pale color carried back in center much as in 



