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 Article V.—NEW SPECIES AND SYNONYMY OF AMERICAN CYNIPIDÆ

Our present knowledge of the Cynipidæ (Hymenoptera), of the number of species, of species limits, and of species and group relationships, is decidedly incomplete. Students of the gall-wasps have been few, and from large areas of the world practically no collections of this family have been made, e. g., in the Western Hemisphere we have seen very little material from the southern and western parts of the United States, from Mexico, or from Central or South America. In consequence, we are hindered considerably in obtaining an understanding of the peculiar biological phenomena characteristic of these insects. The origin and development of gall production, of agamic reproduction, and of heterogeny especially, may be adequately comprehended only through a careful study not only of the species already described but also of many of these species yet to be described. I count it good fortune to be able to offer descriptions of sixteen new species, several of which are important items in the exposition of the very phenomena above mentioned. These species are distributed among most of the genera of the family, in a number of instances representing groups which have been hitherto the least well known, e. g., Aulacidea, Diastrophus, and Disholcaspis. I have also included some new and corrected synonymy.

Certain genera of the Cynipidæ are founded upon definite morphological characters which are clearly paralleled by biological considerations. But many of the species of oak gall producing Cynipidæ have long been held in groups which are based on the most meager of indefinite morphological characters, and the "genera" thus made are not confirmed by a more careful examination of the morphology and a study of the biology of the species concerned. And, moreover, until both of the alternate generations of dimorphic species can be included by a generic definition, the group remains an artificial creation. In another paper, on the phylogeny of the Cynipidæ, I am discussing this question in more detail and offering data which may be used to draw lines for natural genera. I hope to be able in the near future to revise the genera for the family.

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