AMERICAN DIPTERA. 227 



scutellum with two weil-separated erect bristles; tegular cilia golden ; halteres 

 light yellow. Abdomen depressed, cylindrical at tip in male, segments shining, 

 interspaces gray dusted ; hypopygium shining, terminal, but little larger than 

 abdomen, its ventral fringe small, above with a projection bent to the right. 

 Cosie yellow ; legs yellow, except following fuscous to black places: four anterior 

 femora on outer side, except central yellowish portion, hind femora on tip on 

 basal and a})ical thirds, four anterior tibiae on outer side, and tarsi gradually 

 towards tip; front femora much thickened, middle femora moderately, hind ones 

 not; inner side of tibiae and metatarsi of front legs, and femora and tibiae of 

 middle legs provided with small black setulae ; middle tibiae of male with a slight 

 depression before tip on underside. Wings not broad, grayish hyaline, veins 

 strong, piceous, lightly clouded on cross-veins; first posterior cell narrowed 

 towards tip, fourth vein ending just behind wing tip, anal cross-vein strong, a 

 portion of sixth vein beyond anal cross-vein present. 



Seventeen males, nineteen females. The sexes taken in copula- 

 tion. Juliaetta, Moscow and Craig's Mt., Idaho, May. Magdaleua 

 Mts., N. Mexico, August. 



Tachydroinia portsecola Walker. 

 List Diptera, iii, p. 506. 



" Body black, dull ; eyes piceous ; feelers and mouth black, the latter tawny 

 towards the base; abdomen hairy at tip; legs tawny; thighs slightly piceous; 

 wings gray; wing-ribs and veins piceous; poisers dark tawny. Length of body 

 li lines; of wing 3 lines. 



" Hudson's Bay (Barnston)." 



Tachydroinia Wiiilheini Zetterstedt. 

 Dipt. Scand., i, p. 321. 

 Ins. Lap., 548. 



Black. Antennae, palpi, halteres and legs concolorous, metatarsi flavescent ; 

 wings infuscated, third and fourth veins subparallel. Thorax above black, 

 opaque, humeri cinerascent, pleurae shining, black. Coxae sometimes yellow 

 apically. 



New Hampshire (Osten Sacken). 



TachyilroniJa postica Walker (Fig. 53). 

 Trans. Ent. Soc. Lond., N. S., iv, p. 149. 



"Black; antennae, abdomen at the base beneath, and legs testaceous; hind 

 femora and hind tibiae piceous; wings cinereous, veins black, halteres wliitish. 

 Length of body IJ lines; of wings 3 lines. 



"U.S." 



Four specimens from Lawrence, Kansas, agree with this descrip- 

 tion, and may probably belong to Walker's species. They are thus 

 further characterized : 



Dorsum of thorax and occiput lightly cinereous-dusted, pleurae 



TRANS. AM. ENT. SOC, XXVIII. JULY, 1902 



