2 Proceedings of the Biological Society of Washington. 



that of its height posteriorly; frons in front of anterior ocellus occupying 

 about two-fifths the width of head, each orbit at this point over half as 

 wide as interfrontalia; viewed from above frons projects beyond eye half 

 as far as length of latter, third antennal joint rounded at apex, about 

 1.5 as long as second; arista but little longer than antenna; proboscis 

 slender, the apical portion as long as height of head. Presutural acrosti- 

 chals consisting of one long pair of bristles, and a series of weak, paired 

 hairs caudad of them; prealar bristle half as long as the one behind it; 

 scutellum with 4 long bristles. Fore femur with long bristles on postero- 

 dorsal, posterior, and postero- ventral surfaces; fore tibia with 1 posterior, 

 1 antero-dorsal, and 2 preapical bristles; mid femur with 1 or 2 bristles 

 on antero- and postero-ventral surfaces near base, and the usual series 

 on basal two-thirds and the preapical one on anterior surface; mid tibia 

 with 1 anterior, 2 postero-dorsal, and 2 posterior bristles; hind femur 

 with a series of long widely spaced bristles on the antero-ventral surface, 

 and 2 or 3 weak ones on the postero-ventral; hind tibia with 2 antero- 

 ventral, 3 or 4 antero-dorsal, and 3 or 4 postero-dorsal bristles; apex of 

 posterior surface with several long setulose hairs; the apical curved thorns 

 shorter than diameter of tibia. Costa with short setulae and no well- 

 differentiated costal thorn ; veins bare ; last section of fourth vein about one 

 and one-fourth as long as preceding section; outer cross- vein nearly straight. 



Length, 5.5 mm. 



Type locality, Suitland, Md., October 30, 1917, in flower of Gentiana 

 clausa (W. L. McAfee). One specimen. 



Fig. 1. Macateeia protuberans sp. n., female, head ; apex of 

 hind tibia, anterior view ; and apex of abdomen, side view. 



