ART. 3 GENERIC REVISION OF THE FOSSORIAL WASPS PARKER 7 



combination of characters : Lateral expansion of the pronotum form- 

 ing on each side a well differentiated, rounded lobe (tubercle) which 

 does not touch the tegula; posterior metatarsus not dilated; no 

 plumose hairs present; maxillae normal, or if elongate, then the 

 ocelli are more or less reduced or distorted; hind wing always with 

 an anal lobe that is short and lacks an auxiliary vein; abdomen 

 sessile, with the male having seven and the female six exposed seg- 

 ments and the last sternite of the female not turned dorsally around 

 the sting ; three closed cubital cells, of which the second receives both 

 recurrent veins; basal vein removed from the stigma by two or more 

 times the distance from the apex of the radial cell to the apex of the 

 "^ing; stigma small, not wider than the costal cell; neither epicnemia 

 nor episternal suture present ; labrum exserted and often rostrif orm ; 

 mandibles without an external notch. Although the members of this 

 subfamily are thus definitely distinguished from other hymenopterous 

 forms by possessing in common the characters given above, never- 

 theless the two tribes may be distinguished from one another by 

 characters that are equally definite. These are set forth below. 



KEY TO THE TRIBES OF BHMBICINAE 



1. Ocelli normal ; dorso-ventral length of the labrum always less than its greatest 

 width ; tibia of second leg provided with two apical spurs ; submediellan cell 



extending beyond the junction of the mediella and cubitella veins Stizini. 



Ocelli distorted or completely reduced to cicatrices ; dorso-ventral length of the 

 labrum equal to or greater than its greatest width ; tibia of second leg pro- 

 vided with only one spur ; submediellan cell not extending beyond the junc- 

 tion of the mediella and cubitella veins Bemblcini. 



Tribe STIZINI 



Handlirsch in his Monographie der mit Nysson und Bembex ver- 

 wandten Grabwespen, part 6, published in 1892, considered Bei7hbici- 

 nus Costa and Stizoides Guerin as synonyms of Stiztis Latreille, and 

 Fox in his Proposed Classification of the Fossorial Hymenoptera of 

 North America took the same position as Handlirsch. Kohl also 

 considered these two genera synonyms of Stizus Latreille. After a 

 careful study, however, of all available material, which included rep- 

 resentatives of all these genera, I am convinced that the characters 

 on which Bemhicin'u-s and Stizoides were based are of generic impor- 

 tance and I have accordingly given both names generic rank. 



Of the two tribes, the Stizini appear to be the more primitive and 

 therefore the less specialized group. In this tribe the ocelli are 

 normal and the labrum has what may be regarded as the normal 

 form; that is, its greatest width exceeds its dorso-ventral length. 

 The tibia of the mesothoracic leg is provided with two spurs and the 

 submediellan cell extends beyond the junction of the mediella and 

 cubitella veins. 



