184 CRABRONID2. 
b. Mandibles strong, dentate ; two recurrent nervures. 
Genus XXI1V.—Diopontus. Curt. 
Heap large, subquadrate, of the width of the thorax ; eyes oval, 
very distant, placed at the sides of the head; antenne geni- 
culated, a little longer than the head, and inserted at the base 
of the clypeus, not approximated; the scape obconic, the 
second joint subglobose, the rest cylindrical, very slightly in- 
creasing, sometimes subserrate in the males within ; the clypeus 
transverse, tridentate ; labrum emarginate ; the mandibles bi- 
dentate. Tuorax oval; the collar transverse, linear; the 
scutellum transverse, lunulate ; the metathorax short, obtuse ; 
the superior mings mith one marginal cell narroning beyond the 
second submarginal, and two submarginal cells, the first oblong, 
recewing towards its end the first recurrent nervure, the second 
forming an isosceles triangle, truncated at its apex, and re- 
ceiwing the second recurrent nervure ; the legs moderate, slight, 
frequently spinose. The Aspomen subsessile, ovato-conical ; 
the terminal segment in the ¢ constricted at its apex into an 
acute upcurved spine. 
Type, D. tristis. V.d. Lind. 
+4+ The etymology of this genus is Ai, two, and o8ovréw, 
to furnish with teeth, from the emargination of the labrum. 
Mr. Curtis has taken the details from the Pemphredon 
tristis, which he incorrectly makes synonymous with the 
Psen pallipes of Panzer ; this therefore is his type, although, 
in illustration of the genus, he figures a different and new 
species, which, according to my view, belongs to a distinet 
genus, and I consequently separate it as such, and form 
of it, with two others, one of which is the Pemphredon 
ensignis of Vander Linden, the genus Passalecus. Latreille, 
in his ‘ Précis,’ evidently makes a species of the present 
genus the type of his genus Pemphredon, but in his ‘ Genera’ 
he places it in the genus Stigmus, and by his generic de- 
