Fossorial ITymcnoptcra of North America. G5 



covered with silvery, short, stiff pubescence. The clypeal region in* 

 eluding the ch/peus and the two lateral lobes, which can sometimes be 

 distinguished, is closely covered with a silvery pubescence which in 

 certain lights is of a deep golden hue. The clypeus itself is always 

 shorter than broad, ridged in the middle. The front edge is often naked 

 and thickened or produced, cariuate and subacute, and the lateral lobes 

 are very short, being transversely almost linear, of course being much 

 wider in 9 than in £ . Antennae, placed much below the middle of 

 the front, short, generally thickened towards the tip, second joint uni- 

 formly long, and appressed towards front in the groove, cylindrical, 

 rarely flattened in ■% . Mandibles rather large, of even width through- 

 out, which is another good character. Mouth-parts well developed, 

 varying much in the length and size of lingua and maxillae. 



Thorax sub-globular, being convex, rounded above and on the sides, 

 much more globular than in Nyssonidse and Philanthinee. The scu- 

 tellum of the prothorax is distinct from the scutum, and is large, 

 broad, often angulated in front on the sides. Meso-scutum square, 

 about as long as broad, convex, behind narrowing slightly and slightly 

 concave opposite the patagia, and angulated just beyond them, before 

 reaching the hind edge. Scutellum is transversely oblong, being 

 about one-third as long as broad, that is, the notal portion which is 

 raised and distinct from the sides, sometimes it is ( Thyreopus) half as 

 long as broad, and not half as wide as thorax itself. Meta-scutellum 

 one-half to one-fourth as long as the meso-scutellum, being trans- 

 versely linear. 



The propodeum is large, triangular or sub-trapezoidal, since it nar- 

 rows more or less behind. It is bent rather abruptly downwards from 

 withiu the middle, being nearly vertical, and this character aids in 

 giving the globular form to the whole thorax. It is unarmed. 



Fore wings long and rather narrow, the apex somewhat produced, 

 and the outer margin long and rather oblique. The absence of the 

 2 — 3 outer subcostal and median spaces is the best distinction in this 

 group and the Pemphedoninse, since they are present in Nyssonidse and 

 Philanthinx. The costal space is angulated-oval, being truncated at 

 the outer side, and the medio-subcostal recurrent, anastomoses in or 

 near the middle of the costal space ; first subcostal is long oblong, the 

 outer ones obsolete. First median cell elongated, rhomboidal or lo- 

 zenge-shaped, the outer side is generally parallel with the outer-lower 

 side of the costal space, the outer side of first subcostal which is between, 

 being more transverse, being almost perpendicular to the costa of the 



PROCEEDINGS EST. SOC. PHILAD. MAY, 1866. 



