AMERICAN DIPTERA. 229 



Tachyclroniia clavipes Loew. 

 Cent., V, 73. 



Black, shining; legs including coxje largely black, apex of anterior tibiae 

 strongly incrassate, wings beyond the whitish base dark, provided with a poste- 

 rior basal cross-vein. Antennse dark fuscous, proboscis black, palpi white. 

 Hypopygium with short black hairs above. 2.6 nnn. 



Illinois (Le Baron). 



Tachyclrouiia pusilla Loew (Fig. 51). 

 Cent., V, 74. 



Shining, black, proboscis and palpi concolorous, no white spot on the pleurae; 

 coxfe yellow ; anterior legs yellow, except the upper side of the femora and tibiae 

 and the whole of the tarsi ; middle legs like front ones, except that the whole of 

 the tibiae is piceous, femora beneath with black setulae ; hind legs, except lute- 

 ous base of the femora, piceous. Wings cinereous, outer half of costal margin 

 infuscated, no posterior cross-vein. 2 mm. 



Illinois (Le Baron), Snow, Wheeler; Massachusetts (Hough). 



Tachydromia rostrata Loew. 

 Cent., V, 72. 



Black, antennai yellowish, palpi white, proboscis yellow, except tip. Thoracic 

 dorsum subopaque, pleurae shining. Coxae yellow ; legs yellow, posterior femora 

 and all the tibiae partly fuscous ; middle tibiae before apex slightly emarginate. 

 This emargination is not readily seen. Wings subfuscous, whitish basally, with 

 a posterior cross-vein. 3 mm. 



Hew Hampshire. 



Tachydromia rapax Loew (Fig. 55). 

 Cent., V, 71. 



Black ; wings subfuscous, at base whitish, with a posterior cross-vein. Coxae 

 yellow, with a black spot, trochanters black beneath, anterior femora with an 

 apical dot on posterior side, united on under side to a basal dot on the anterior 

 side; front tibiae fuscous, apical third of posterior tibiae dark; middle tibiaj 

 excised before apex. 3 mm. 

 Illinois (Le Baron). 



Specimens of this species are in the collection from Massachu- 

 setts, Indiana, Illinois, Wisconsin and Wyoming. 



COIiOBOIVEURA gen. nov. 

 Thick set. Head globose, longer than wide, wider than deep; 

 eyes small, two-thirds the head height, inserted forwards and there 

 fore the occiput large; three ocelli present, the posterior two ap- 

 proxinjated ; occiput with stiff black bristles, longer on the upper 

 vertex and between the ocelli ; front narrowed mid-way between the 

 ocelli and the antennse ; eyes notched at the antennse ; distance from 

 the antennae to the bottom of the labrum equal to that from the 



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



