A REVISION OF HYMENOPTEROUS INSECTS OF THE TRIBE 

 CREMASTINI OF AMERICA NORTH OF MEXICO. 



By R. A. CusHMAN, 



Of the Bureau of Entomology, United States Department of Agriculture. 



As defined by Ashmead, the tribe Cremastini is distinguished 

 from the Porizonini by the obsolescence in the latter tribe of the 

 base of the middle vein in the hind wing and by the thickening of the 

 anterior end of the basal vein in the front wing. Aside from the 

 question as to whether these characters, as interpreted by Foerster, 

 who proposed them, are good or not, the fact remains that the 

 genotype of Cremastus has the middle vein obliterated at the base, 

 and by no means all of the genera at present referred to the Pori- 

 zonini exhibit the thickening of the basal vein. Foerster * made use, 

 also, of the angulation of the radial abscissae, ascribing to the Pori- 

 zonini a right angle and to the Cremastini an obtuse angle. The 

 strict interpretation of this character separates species much more 

 closely aUied to each other and to Cremastus as represented by the 

 genotype, than either is to Porizon as represented by the genotype. 



The relation between the length and breadth of the stigma as used 

 by Foerster to separate his Cremastoidae from the families which 

 follow it in his arrangement can not be used, since several species of 

 Cremastus have the stigma distinctly less than half as wide as long. 

 Also the occipital carina varies in Cremastini from widely inter- 

 rupted above to complete. 



The genera of these two tribes, however, form two rather well- 

 defined groups, separated by propodeal, abdominal, and venational 

 characters, as indicated in the following tabulation: 



Propodeum not extending beyond base of hind coxae; abdomen usually short 

 and stout, not or but weakly compressed, the second tergite not very much 

 longer than vride, most frequently transverse, and with the sides ^\^dely 

 divergent; angle of radius right or acute, touching or very close to cubitus, 

 the intercubitus being very short and not or but very little longer than that 

 portion of cubitus between it and recurrent, most frequently shorter, all 

 veins at this point being nearly interstitial; ovipositor most frequently short 

 and upcurved Porizonini. 



> Vcrh. Nat. Ver. Preuss. Rhcinl., vol. 25, 1S68, p. 141. 



Proceedings U. S. National Museum. Vol. 53- No. 2219. 



503 



