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
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