Fossorial Ihjmcnoptcra of North America. 401 



narrower, clypeal region coarsely pubescent, silvery, clypeus and labruni 

 ;;s iii P. leucopw ; mandibles black, palpi piceous, dark ; antennae black 

 at base, (remainder wanting in the single specimen at hand). Scutum 

 and scutcllum smooth and polished, with scattered shallow minute 

 punctures. Propodeum with a short broad flattened triangular enclo- 

 sure, not so distinct as in the other species, with four rugae on each 

 side of the mesial furrow, which is broad, well marked, with high 

 sides, and more regularly diamond-shaped than in the two preceding- 

 species, with two or three transverse rugae at bottom; posteriorly the 

 sides of this segment are suddenly tumid, owing to the much depressed 

 sunken mesial furrow, which is deeply excavated, and bounded by 

 ridges; surface coarsely rugose, with broad, shallow fossae. Wings pale, 

 nervures dark-brown ; tegulre brown, uniformly fuscous at base. Abdo- 

 men very elongate, long and narrow, with parallel sides, oblong, oval, 

 much flattened, sutures very distinct, pedicel longer than the abdomen 

 is wide, grooved laterally, smooth and polished, entirely black, tip sub- 

 mueronate, acute, upper surface plane, not grooved. 



Length of body, .26; head and thorax, .10; abdomen, .16 inch. 



Illinois. (Coll. Ent. Soc. Phil.). 



At once easily recognized by the long-pedicelled abdomen which is 

 oblong ovate, greatly flattened, mucronate, sutures deeply impressed; 

 its long pedicel, and black body, also by the head retreating posteriorly 

 more than usual, with a more convex, elevated vertex, and by the 

 singular mode of sculpturing of the posterior part of the propodeum. 



Psen chalcifrons, n. sp. 



9 . Head black, much narrower transversely than in Psen nrger; 

 vertex more convex; ocelli more contiguous and more prominent, 

 scarcely pubescent above the insertion of the antennae; a slight cleft, 

 v-shaped carina between the origin of the antennae; below covered 

 with a peculiar brassy, silvery pubescence, purely bronzen when seen 

 in some lights; mandibles entirely black; scape of antennae black; 

 flagcllum very clavate, pale reddish beneath, extending onto the sides. 

 Surface of the thorax scarcely polished, rather densely, but finely 

 puncto-striated; scutellum polished, with a few slight shallow, scattered 

 punctures; meta-scutellum with fine parallel rugaa, more regular and 

 better marked than in P. niger. Enclosure on the propodeum broad, 

 subequilateral, extending lineally to the insertion of the abdomen, with 

 four regular thin distinct parallel rugae, slightly oblique and directed 

 outwards, parallel with the walls of the mesial furrow, which poste- 

 riorly, rapidly expands into a lozenge-shaped area; sides of the propo- 



PROCEEIHSGS ENT. SOC. rillLAD. FEBRUARY, 1867. 



