PART II. 

 Systematic Larridae. 



The following keys will serve to separate the family Larridae 

 from other aculeate wasps : 



Fore wings longitudinally folded in repose Series Diploptera 



Fore wings not longitudinally folded in repose Series Fossores 



FOSSORES. 

 Pronotum and tegute in contact; a transverse chink between ventral 



abdominal segments 1 and 2 Scoliid^ and Mutillid^ 



Pronotum and tegulae in contact; no transverse chink between ventral 



abdominal segments 1 and 2 PompiliDjE 



Pronotum and tegulse not in contact Sphegoidea (Spegid^ sens, lat.) 



Sphegoidea. 



1. Middle tibia with two apical spurs. . Sphegid^, Nyssonid^, Stizid^, 



Mellinid^e 

 Middle tibje with but one apical spur or with none 2 



2. Abdomen with a strong constriction between first and second seg- 



ments, the first segment much narrower, therefore, at apex than 



the second Philanthid^ 



Not having the above characters 3 



3. Abdomen elongate and clavate, the first segment petioliform; eyes 



deeply and narrowly emarginate within; fore wings with usually 



but one well-defined submarginal cell Trypoxylonid.*: 



Abdomen not as above ; eyes never deeply emarginate within 4 



4. Only one complete submarginal cell in the primaries; head very ro- 



bust, subquadrate; metathorax sometimes spinose. .Crabronid^e 

 At least two complete submarginal cells in the primaries, the second 

 of these cells sometimes petiolate; head normal, rarely vei-y 

 stout; metathorax never spinose 5 



5. Abdomen petiolate or subpetiolate, the petiole or subpetiole (which 



is often quite short) distinctly marked off from the remainder 

 of the abdomen, not cylindrical ; first discoidal cell of fore rarely 

 if ever longer, usually distinctly shorter, than the marginal cell; 

 marginal cell lanceolate, its apex pointed on the costal margin of 

 the wing; two submarginal cells, the second not petiolate; stigma 



strong, often very marked; ocelli perfect Pemphredonid^ 



Abdomen tapering to a point at its junction with the thorax; sub- 

 petiole, if present, not clearly differentiated from the rest of the 

 abdomen; first discoidal cell of primaries usually distinctly longer 

 than the marginal, which is more often truncate or rounded at 

 apex; two or three submarginal cells, the second sometimes 



petiolate ; ocelli variable 6 



(137) 



