208 Proceedings of the Biological Society of Washington. 



Female. — Similar to the male in color. The eyes are almost bare, the 

 frons is one-third of the head width, widened anteriorly, and the postero- 

 ventral surface of hind femur has no median bristles. 



Length, 8.5-10 mm. 



Type, male, Chester, Mass., August 3, 1911. Allotype, Gt. Barrington, 

 Mass., June 15, 1915 (C. W. Johnson). 



This species is most closely allied to errans Meigen, but differs in having 

 pale palpi and the antennae partly pale. 



Phaonia flavibasis, sp. n. 



Male. — Black, slightly shining, thorax and abdomen partly yellowish 

 testaceous. Head black, orbits, face, and cheeks densely silvery prui- 

 nescent; orbits on inner margins, anterior half of parafacials, facial ridges, 

 cheeks, first, second, and base of third antennal joints, and palpi yellowish 

 testaceous. Mesonotum distinctly quadrivittate ; humeri and scutellum 

 yellowish testaceous. Basal half of abdomen yellowish testaceous. Legs 

 yellowish testaceous, tarsi subfuscous. Wings, calyptrae, and hal teres 

 yellowish. 



Eyes sparsely pubescent, separated at narrowest part of frons by a little 

 less than width across posterior ocelli, the interfrontalia obliterated at 

 middle of frons; third antennal joint twice as long as second; arista with 

 sparse hairs, the longest of which is about as long as width of third antennal 

 joint; parafacial in profile narrower than third antennal joint; cheek about 

 one seventh as high as eye. Presutural acrostichals absent, one pair in front 

 of scutellum; postsutural dorso-centrals 4; prealar bristle less than half as 

 long as the one behind it; hypopleura bare; sternopleurals 1:2. Basal 

 abdominal sternite bare; fifth sternite with a rather small rounded pos- 

 terior excavation. Fore tibia unarmed at middle, the antero-dorsal apical 

 bristle very weak ; mid tibia with three or four posterior bristles ; hind femur 

 with about eight rather short bristles on apical half of antero-ventral sur- 

 face and a few short hairlike bristles on basal half of postero- ventral surface; 

 hind tibia with from three to five antero-ventral and two antero-dorsal 

 bristles; calcar not very long. Venation normal; outer cross- vein curved. 



Length, 6.25 mm. 



Type, Chester, Mass., May 28, 1912 (C. W. Johnson). One male. 



Structurally this species very closely resembles bysia Walker (apicata 

 Johannsen), but that species differs in color and in bristling of the thorax. 



Phaonia aberrans, sp. n. 



Male. — Black, densely grayish pruinescent. Orbits and parafacials sil- 

 very, face and cheeks whitish pruinescent; second antennal joint, base of 

 third, and palpi except apices reddish. Thorax inconspicuously quadri- 

 vittate. Abdomen in type greasy, but apparently marked as in rufibasis. 

 Legs reddish testaceous, coxae, and femora except apices blackened, tarsi 

 slightly darker than tibiae. Wings slightly brownish, cross-veins narrowly 

 infuscated. Calyptrae whitish. Halteres with the knobs brown. 



