216 NORTH AMERICAN SCELIPHRON (hYMENOPTERA) 



in addition to depressed regions along the inner basal portion of 

 each filamentous segment, they have somewhat oval to oblong, 

 bare, brown to blackish areas on the distal end of these segments. 

 These areas when cleared are seen to be covered with small pits 

 and hairs closely packed, and are a distinct contrast to the larger 

 and more scattered pits on the inner basal portions of the seg- 

 ments. These brownish areas occur, as far as could be deter- 

 mined, only on the seventh, and eighth segments in cyarieum and 

 on the seventh, eighth and ninth, and occasionally sixth, seg- 

 ments in zimmermanni , and vary in size and shape. In both 

 species there are also minute slightly raised areas near the basal 

 end of all the segments of the filament, but the nature of these is 

 undetermined. They are seen on the upper part of the inside of 

 the segments when the antennae project forward. 



Analytical Keys 



A very good working table of the families of the Sphecoidea is 

 given by Ashmead^ and should be consulted by those interested. 

 The following table of the subfamilies of the Sphecidae has 

 been taken from those given by Ashmead^ and by Fernald,^ with 

 slight variations, in connection with the subfamily Sceliphroninae. 



Analytical Key to Subfamilies 



1. Second cubital cell receiving only the first recurrent vein; the second recur- 



rent vein received by the third cubital cell, or at least beyond the second 

 tranverse cubital. (Both recurrent veins are received V)y the first cubital 



cell in a few extra-limital forms) 2 



Second cubital cell receiving both recurrent veins, or the second recurrent 

 vein is interstitial with the second transverse cubitus, although sometimes 

 the first recurrent is interstitial with the first transverse cubitus, or then 

 received by the first cubital cells 3 



2. Antennae inserted on the middle of the face; claws with one to six teeth 



beneath; tibiaj strongly spinous, or at least never with weak or feeble 

 spines; tarsal comb in female present (except in Isodontia). 



Chlorioninae (Sphccinae of Authors) 

 Antennae inserted far anterior to the niiildlt' of the face; claws simple, with- 

 out teeth, or at most with a single small tooth near the middle; tiliia' 

 smooth, not spinous ; tarsal comb in female never present Podiinae 



1 Canadian Entomologist, xxxi, 152. 



2 Idem, 348. 



^ Digger Wasps of North America, Proc. U. S. Nat. Mus., xxxi, 308. 



