1893.] NATURAL SCIENCES OF PHILADELPHIA. 487 



scarcely silvery; head and thorax beneath with long, fuscous pu- 

 bescence; the abdomen when viewed from behind, shows a sparse 

 silvery pile, which is most obvious at apex of second dorsal segment; 

 the ventral segments of abdomen possess a few long, black hairs or 

 bristles; wings dark fuliginous, iridescent. Length 17 mm. 



$ . — Antenna? somewhat shorter and stouter than in the 9 > the 

 first joint of flagellum in length about equal to the second; space 

 between the eyes at the top slightly less than the length of the pedi- 

 cellum and first joint of the flagellum united; anterior margin of 

 clypeus produced medially; hind femora with scarcely any swelling 

 at base beneath, the remaining femora beneath not at all incurved, 

 strongly convex; apical margins of segments 1-3 when viewed 

 from behind with silvery pile; wings colored like the female. Length 

 12 mm. 



New York and Georgia. 



ANCISTROMMA gen. nov. 

 Body tolerably stout, never densely pubescent; mandibles widely 

 emarginate on outer margin, armed with two teeth within; antenna? 

 tolerably stout, in length variable, usually longer than in either 



Tachytes or Tachysphex, the scape not elongate as in those two genera, 

 but short and stout ; eyes always converging towards the vertex, the 

 convergence different in the various species; posterior ocelli linear 

 at the top broadened and furrowed, which gives them the appearance 

 of being formed into a hook ; anterior ocellus round, well-developed; 

 the head in front is distinctly, though not strongly as in Larva and 

 Xotogonia raised or swollen along the inner eye margin ; face behind 

 the base of antenna' not bitubereulate, at the most presenting a slight 

 swelling; prothorax better developed than in either Taehytes or Ta- 

 chysphex, in some species reaching the level of the dorsulum; sculp- 

 ture of thorax rather coarse; tibia? and tarsi of all the legs strongly 

 spinose, middle tibia' with a single spur; pulvilli large; claws long as 

 in Notogonia, entire; fore femora, of $ near the base emarginate and 

 still nearer the base drawn out iido a tooth, fore tarsi of 9 with a 

 comb, composed of short stout thorns, in the $ this comb is also pres- 

 ent but is much weaker, anterior tibia? on outer side without spines or 

 bristles; last dorsal segment of 9 with a large, coarsely sculptured 

 Sind clotlied uitli pubescence on apical portion, pygidial area; in the 



$ the eighth ventral segment is not emarginate. 4 Marginal cell of 



4 One species A. vegeta, however, has this segment emarginate. 



