856 



quite invisible from above on account of the rather large wings of the 

 male, which were folded closely over the abdomen. It is quite possible 

 that it is by this means that the females find their way from one nest 

 to another, as they are themselves not well adapted to do so. 



Coquillett's species is recorded as occurring in a situation where no 

 ants' nests were within easy reach. 



ANTHOMYID^ 



POGONOMYIA FLAVINERVIS, n. sp. 



Male. — Glossy black. Frontal and facial orbits slightly brownish, 

 covered with dense silvery pilosity. Thorax with slight, but distinct, 

 grayish pruinescence. which when viewed from in front gives the disc 

 the appearance of being trivittate anteriorly. Abdomen when viewed 

 from behind distinctly gray pruinescent on sides, leaving only a rather 

 narrow dorso-central black line which is more or less interrupted at 

 apex of each segment. Legs black. Wings slightly tinged with yellow, 

 all veins yellow, costa with black setulose hairs. Calyptrae whitish, 

 margins yellowish. Halteres brown, knobs dark brown. 



Eyes distinctly separated, orbits each about as wide as central stripe 

 at narrowest part of frons; frons at narrowest part as wide as distance 

 between outer margins of the posterior ocelli ; the strong pair of ver- 

 tical macrochastse much more conspicuous than the postocular bristles ; 

 arista short-haired ; head otherwise similar to that of alpicola. Thorax 

 with the macrochsetse and hairs as in alpicola but much weaker. Abdo- 

 men rather narrow and distinctly tapering apically, the macroch^eta? 

 and hairs much less conspicuous than in alpicola. Legs with the arma- 

 ture much as in alpicola; mid femora with the antero-ventral surface 

 armed with a series of 8-9 bristles, which begins before middle and ex- 

 tends to apex, the longest bristle being slightly beyond the middle of 

 the series; postero-ventral surface with a series of 8-9 longer and 

 more hairlike bristles extending from base to a point about one third 

 from apex, the bristles increasing in length from base to apex of series ; 

 hind femora with the series of bristles on antero-ventral surfaces much 

 less numerous than in alpicola; postero-ventral surface with a single 

 long slender bristle about one third from apex (two smaller and weak- 

 er ones in alpicola^ ; hind tibiae with armature like that of alpicola ex- 

 cept that the bristles are distinctly weaker. Wing venation similar to 

 that of alpicola. 



Female. — Agrees in color with the male except that the abdomen is 

 almost entirely glossy black. 



