AMERICAN DIPTERA. 227 



seutelluni with two well-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. 

 Coxai 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 apical thirds, four anterior tibise on outer side, and tarsi gradually 

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

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

 middle legs provided with small black setulaj ; middle tibise 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. Magdalena 

 Mts., N. Mexico, August. 



Tacliy«lroniia portseeola 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 

 a lines; of wing 3 lines. 



"Hudson's Bay (Barnston)," 



Tachydromia Wiiithemi Zetterstedt. 

 Dipt. Scand.. i, p. 321. 

 Ins. Lap., 548. 



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

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

 opaque, humeri einerascent, pleurse shining, black. Coxfe sometimes yellow 

 apically. 



New Hampshire (Osten Sacken). 



Tachydromia postica Walker (Fig. 53). 

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



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

 femora and hind tibise piceous; wings cinereous, veins black, halteres whitish. 

 Length of body li 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, pleurse 



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



