64 AMERICAN BLACK FLIES OR BUFFALO GNATS. 



curved outward at anterior extremity, and convex on the posterior 

 half; pleura^ gray pollinose, scuteUnm and postscntellum gray polli- 

 nose. Basal abdominal scale gray and next three segments broadly 

 black-brown, opaque, on dorsum, lateral margins gray pollinose, next 

 segment more narrowly blackened on dorsum, the lateral margins and 

 remaining segments gray j)ollinose. Legs black; generally only the 

 bases of tibise yellow^ but occasionally, in immature specimens, the 

 black color is confined to the apices of femora, bases and apices of 

 tibiae, and apices of tarsal joints. Wings clear. Halteres yellow. 



Frons at upper angle barely more than one-fifth tlie head width, 

 slightly converging toward antennae, the surface with short, white, 

 decumbent pilositj^ ; face distinctly wider than widest part of frons, 

 and longer than wide, the surface with pilosity similar to that on 

 frons; antennal pile short and inconspicuous, whitish; palpi Avith 

 short whitish pile. Scutum with closely placed pilosity which is hair- 

 like, yellowish white in color, and adheres closely to surface, becom- 

 ing slightly longer, but not upright, posteriorly ; scutellum with much 

 longer pilosity, which is concolorous with that on scutum and upright 

 on margin; pleural tuft whitish, postspiracular area bare. Basal 

 abdominal scale with pale fringe ; the hairs on segments of abdomen 

 short and pale. Legs normal in shape; fore tarsi very slightly thick- 

 ened, the apical, paired hairs not distinguishable; hind tarsi with 

 distinct scale and dorsal excision on second joint; claws bifid; surface 

 of all legs with pale hairs, which are most conspicuous on the tibiae, 

 giving them a whitish appearance. 



Male. — Deep black, opaque. Face silvery pollinose; antennae and 

 palpi black. Scutum with rarely a slight silvery pollinosity poste- 

 riorly and on the lateral margins, and otherwise velvety black; 

 pleurae slightly covered with white pollinosity; scutellum velvety 

 black ; postscutum slightly pollinose, glossy. Abdomen velvety black, 

 only the venter yellowish, no silvering noticeable on any of the speci- 

 mens before me ; hairs on surface short, yellowish. Legs colored as 

 in the female, surface hairs yellow, with an admixture of longer 

 brown upright hairs on the dorsal surfaces. Wings clear, veins pale 

 3^ellowish, the thin veins very indistinct. Halteres brown. 



The head is formed as in other species of this genus, the upper eye 

 facets being conspicuously enlarged while the lower half of the eye 

 has small facets. The scutum is thickly covered with pile, which is 

 golden yellow in color and rather more scalelike than that of the 

 male; there are no upright hairs on disk, and posteriorly the pilosity 

 is decumbent as in the female; scutellum with yellowish pile and 

 upright brownish hairs on margin. Basal fringe of abdomen brown- 

 ish, the surface hairs also brown. Fore tarsus slender; hind tarsus 

 only slightly dilated ; apical paired hairs absent from fore tarsus, or 



