Fossorial Hymen opt era of North America. 385 



than the head and thorax together; the tip is thickened in 9 , the up- 

 per surface flat, and presenting an oblong, flat area, from which the 

 Bides fall away rapidly, there being no raised ridge as in the Philan- 



thinje. 



STIGMTJS, Jurine. 

 Stigmus, Jurine, Hym. p. 139. (1804). 



% . Head very transverse, being much shorter than usual and very 

 broad, about one-third as long as broad; eyes very prominent, reaching 

 considerably behind the ocelli ; sides of the head behind narrower, con- 

 tracting and rounded immediately behind, so as to give a trapezoidal 

 form to the head; vertex high and convex, in front of the ocelli de- 

 pressed below the level of the eyes, which arc thus rendered very pro- 

 miuent. Ocelli placed in a narrow acute triangle, below the level of 

 the eyes, with a well impressed mesial line in front. The front con- 

 verges from the lower edge of the eyes, so that opposite the insertion 

 of the antennae it is one-fourth narrower than above. Clypeus angular 

 in front, produced, transversely short, lozenge-shaped, with rounded 

 angles, surface not carinate ; mandibles long and slender, not dilated 

 towards the acutely bidentate tips; antennae long and slender, filiform, 

 not thickening at all toward tip ; scape thickened ; thorax convex, gib- 

 bous above, sub-mesial, mesial and parapsidal lines distinct; surface 

 smooth, scarcely punctured; sides puncto-lineated. Legs slender, 

 joints long and slender ; wings with the pterostigma unusually large, 

 being three times as large as in Cemonus and Pemphredon ; 3d costal 

 cell triangular, the side remarkably straight, small, as it is encroached 

 upon by the pterostigma ; 1st sub-costal hardly twice as long as broad, 

 2d exactly square, outer side or second sub-costal median recurrent 

 situated on the outer 3d of ring, while in Cemonus it is situated on the 

 outer 5th ; 2d median very regularly rhomboidal, twice as long as 

 broad, no third cell; 2d sub-median with opposing regularly curved 

 sides, sub-elliptical in form, directly transverse, where in Cemonus and 

 Pemphredon both sides or recurrents are directed obliquely outwards; 

 no nervules present on the outer half of the secondaries; end of the 

 middle cell rounded externally, as no abortive nervules are thrown off 

 beyond. Propodeum much longer than in either Pemphredon or Ce- 

 monus, but shorter than in Passakecus, with no distinct enclosure, it 

 being obsolete. The posterior portion of the propodeum covered with 

 a net-work of fossulets; abdomen with a long pedicel, as long as the 

 body is broad, ridged, much longer and slenderer than in Cemonus, 2d 

 suture somewhat constricted ; the body of the abdomen long-ovate, 

 lanceolate, posterior sutures not so impressed as in Passalseeus. 



PROCEEDINGS EST. SOC. PHILAD. FEBRUARY, 1867. 



