156 Journal New York Entomological Society. |Vo1. iv. 



front edge, with a long oblique testaceous line, a little angulated oppo- 

 site the base of the clypeus. Antennal tubercle situated on the outer 

 edge of a round area opposite the base of the clypeus ; supra-clypeal 

 piece obtuse, the suture separating it from the epicranium indistinct. 

 Clypeus transverse, half as long as broad ; the sides very oblique, 

 marked by testaceous oblique lines; front edge straight. Labrum 

 broad, being one-third as long as broad ; thin, flat, bilobate, overlapping 

 the mandibles, but so thin and expanded that they can be seen through. 

 Mandibles unusually short, stout, thick and broad, not much longer 

 than broad, unidentate, the outer edge produced into a short obtuse 

 point ; within curved towards the retreating inner edge. Maxillae 

 smaller and slenderer than usual, ending in the maxillary palpi, which 

 are short papillae. Labium as usual, with two papilliform palpi, be- 

 tween which is the rudiment of the lingua, forming a transverse chit- 

 inous line. In my two alcoholic specimens the head is bent upon the 

 breast, nearly reaching the middle of the body. The body is very 

 short and broad, dilating in the middle. The end is unusually acute, 

 the lateral region is more prominent, convex and tuberculated than any 

 of the genera of other allied families ; much more so than in Odynerus. 

 The segments are unusually short, dorsally thickened posteriorly, giv- 

 ing a serrate appearance to the outline of the body, the tip sternally is 

 much exserted and of the same size with the tergite ; the two forming a 

 terminal rounded knob. 



In its round flattened head bent forward and under the body, the 

 broad transverse clypeus and broad short bilobate thin transparent 

 labrum, and especially the one-toothed, short, broad mandibie which 

 differs entirely in form from the other genera previously noticed, we 

 probably have mostly family characters separating the Pompilidae from 

 the Sphegidae and Larridte and other families. It widely difi'ers from 

 the larval Pelopceus in its short flattened body and prominent pleurites, 

 and thickened rings generally, but it approaches it in the head-char- 

 acters, which are the most reliable, in its transverse clypeus and thin 

 bilobate labrum, and in the short mandibles; but they are still much 

 stouter, and the clypeus and labrum are less exserted, while the head is 

 shorter, broader and rounder. 



Chalybion cc&ruleum (Lin/i.). 



Larva. — The specimens occurred at Kelly's Island, Ohio. 



Head longer than broad ; full convex, with a slight mesial impres- 

 sion ; the anterior and inner edge of the eyes marked by a curvilinear 



