J. R. MALLOCH 243 



30. Entire insect including legs, antennae, and palpi black 31 



— At least some part of legs, antennae, or palpi j-ellowish or reddish. . . .40 



31. Hind femur of male very much curved, very conspicuously swollen on 



ventral surface about one-third from apex, the apex of swollen part 

 furnished with a tuft of long downwardly directed bristles, that part of 

 surface from tuft to apex with short stiff hairs; ej-es separated by less 

 than width across posterior ocelli frenata (Holmgren) 



— Hind femur straight or but slightly curved and not as above 32 



32. Prealar bristle at least half as long as the one behind it 33 



— Prealar bristle not over one-third as long as the one behind it 38 



33. Thorax with three pairs of dorsocentral bristles 33a 



— Thorax with four pairs of dorsocentral bristles 34 



33a. Arista almost bare; fore tibia with one or two median posterior bristles 



in female; fore tarsus without fine erect hairs basall}'. 



alticola new species 



— Arista plumose; fore tibia in female without posterior median bristle; 



fore tarsus as above azygos new species 



34. Bases of wings and the caljT^trae bright orange yellow 35 



— Bases of wings and calyptrae not bright orange j'ellow, the latter some- 



times pale j'ellowish 3G 



35. Halteres orange yellow; mid and hind femora without conspicuous 



bristles on ventral surfaces except on anteroventral surface of the latter. 



citreibasis Malloch 



— Halteres with black knobs; anteroventral and posteroventral surfaces of 



mid and hind femora with strong bristles, those on posteroventral 

 surface of hind pair not extending to apices . . atrocitrea new species 



36. Frons of male at narrowest part not wider than third antennal segment; 



calyptrae white, the lower one with the margin fuscous and much darker 

 than the disc; longest hairs on arista distinctly longer than its basal 

 diameter dissitnilis new species 



— Frons of male at narrowest part much wider than third antennal segment ; 



calyptrae white or j'ellowish, the margin of lower one not conspicuously 

 darker than the disc; longest hairs on arista not as long as its basal 

 diameter 37 



37. Calyptrae yellowish; basal al)dominal sternite bare; glossy black species; 



the thorax and abdomen without di.'<tinct pruinescence or markings. 



imitatrix Malloch 



— Calyptrae white; basal abdominal sternite hairy; thorax and abdomen 



with distinct pruinescence, the former with four black vittae, the latter 

 with a black dorsocentral vitta albocalyptrata Malloch 



38. Hind femur straight, with long fine bristles on entire length of antero- 



ventral and basal half of posteroventral surfaces; cah'ptrae fuscous; 

 basal abdominal sternite bare fuscisquama (Van der Wulp) 



— Hind femur slightly curved, dilated on apical tliird and with closely 



placed bristles from one-third or more of the femoral length to apex 

 on anteroventral and posteroventral surfaces, the bristles becoming 

 longer apically; calyptrae yellowish or whitish; basal abdominal sternite 

 with one or two fine hairs 39 



TRANS. .\M. KXT. SOC, XLVIII. 



