20 PEOCEEDINGS OF THE NATIONAL MUSEUM vol.73 



Goniomyia unifasciata Sherman, Journ. Econ. Ent., vol. 8, 1915, p. 299. — 



Brixton, Check-List Dipt, of v onn., 1920. 

 Triachora unifasciata Townsend, Muscoid Flies, 1908, p. 105. 



Male. — Front at vertex 0.36 to 0.39 of the head width, the eyes 

 not diver^mg very much to the lower part of the face. Parafrontals 

 with a little pale pollen below, most of the surface dark and subshin- 

 ing. Frontal bristles in three irregular rows, with the addition of two 

 or three proclinate orbitals. Below the lowest frontals are some 

 rather conspicuous dark hairs which in some specimens and at some 

 angles may appear pale in color, at least partly. Face and paraf acials 

 white, almost silvery, the former rather broad on the lower part and 

 the latter considerably narrower below than in most species. Cheek 

 about one-fourth the eye height with yellow pollen and mostly black- 

 ish hairs. Antennae red at base, third joint black, nearly four times 

 the second. Arista flattened in a uniform width almost to the apex. 

 Vibrissae not very far above the mouth, the distance a little less than 

 second antennal joint; facial ridges bristly almost to the arista. Palpi 

 yellow; beard white. 



Thorax black, rather densely gray pollinose, the stripes slender. 

 Scutellum entirely black. 



Abdomen black, gray pollinose on the first and second segments, 

 the latter more shining at tip; third segment with pollen slightly 

 more yellowish; fourth segment with deep golden pollen to apex. 

 First and second segments each with a single pair of median mar- 

 ginals; third and fourth with a marginal row. 



Legs black, front pulvilli minute; hind tibia with coarse sloping 

 bristles mixed with hairs on the outer side. 



Wings light brown. Calypters white, the margin a little darkened. 



Female. — Front at vertex 0.36 of the head width, the same in three 

 specimens. Facial ridges more flattened than in the male. Third 

 antennal joint hardly twice the second. 



Length, 9.5-11 mm. 



About 100 specimens of this species have been examined. Those 

 belonging to the National Museum collection include the following: 

 Two types of Exorista flavicauda Riley from Missouri; 1 specimen 

 from Georgia; 2 from New York (Southwick); 38 from the District 

 of Columbia and adjacent Virginia and Maryland, collected by Town- 

 send, McAtee, Shannon, Greene, Quinter, and Aldrich; 14 from 

 Mount Holyoke Gap, Mass. (Townsend); 1, Clarke County, Va. 

 (Aldrich); 2, Chesapeake Beach, Md. (Aldrich). In the Aldrich col- 

 lection, recently donated to the National Museum, are 18 specimens 

 from Lafayette, Ind., and 4 from Ghent, N. Y., 2 from Castle Rock 

 and Fern Rock, Pa. (Harbeck); 1, Habana, Cuba (C. F. Baker). 

 From Dr. A. L. Melander three specimens were received, one from 

 Dixie Landing, Va. (Townsend); one from Pennsylvania and one 



