INDIANA UNIVERSITY STUDIES JUNE, 1922 STUDY No. 53 STUDIES OF SOME NEW AND DESCRIBED CYNIPIDÆ (Hymenoptera). By ALFRED C. KINSEY, Assistant Professor of Zoology, Indiana University. VARIETIES OF A ROSE GALL WASP. By ALFRED C. KINSEY and KENNETH D. AYRES. Studies of Some New and Described Cynipida (Hymenoptera)' By ALFRED C. KINSEY, Assistant Professor of Zoology in Indiana University THIS paper, with the appended paper, offers descriptions of 107 American gall wasps, 70 of which have not been previously described, revises Plagiotrichus, a genus not heretofore recognized in the American fauna, recognizes one new genus, Heterocus, and offers some data on the variation, distribution, life histories, and phylogeny of the insects. Seventy of the cynipids described are from the Pacific Coast of the United States. Probably the most notable departure in this paper is the recognition of varieties. No varieties have been recognized previously in American Cynipidæ, and only a very limited use has been made of them in Europe. This is too true for most fields of entomology. Two practices have been followed: closely similar forms have been considered as haphazard variations of one species; or varieties have been considered as distinct species, as have 18 of the varieties treated in this paper, belonging to seven species. However, variations are usually orderly and abrupt, and much biologic data has been buried by ignoring minor differences. In many cases where the related forms were described as distinct it was due to ignorance of previously described forms, and they have been maintained as distinct by later workers thru continued ignorance of the meanings of the descriptions. Most of these descriptions are truly unusable because they make no comparisons with other forms, and usually fail to describe the very characters in regard to which there is any variation. Great confusion has been introduced by the reduction to synonomy of these related things; in the process much biologic data has been scrapped, not to be recovered without difficulty. I acknowledge having copied all of these practices in my own previous publications. 1Contribution from the Zoological Laboratory of Indiana University No. 186 (Entomological No. 2). It cannot be hoped that I have now entirely untangled the confusions regarding even the species treated in this paper, but perhaps my method will ultimately prove profitable. By the use of trinomials the specific unity of a group is recognized, and means are provided for the introduction of comparisons to discover the character of the variations and possibly some of the factors; to distinguish differences in physiologic characters such as host preference, gall form, date of emergence, and occurrence of heterogeny, in regard to all of which closely related varieties may vary; and to give a basis for the understanding of questions of distribution. The only possible objection to the recognition of varieties will be the less convenient nomenclature necessary, but this is not a great consideration in view of the advantages of the practice. In recognizing the limits of varieties these are the general rules I follow: (1) The morphology of the adult insect, rather than the gall characters or other such data, is the prime consideration. (2) Any character, no matter how trivial or intangible, is of importance if it is constant in any large proportion of individuals. (3) No variety is based on trivial morphologic characters alone; physiologic characters as expressed in the structure of the gall, in the choice of host, geographic distribution, or other general biologic characteristics always contribute evidence for a similar interpretation. (4) Conversely, no single sort of biologic data, nor set of such data, is the basis for recognizing a variety unless it is paralleled by morphologic evidence. (5) No variety has been designated unless at least one of the varieties of the species is represented by material from more than one locality. If there is any exception to the above rules, it is because the data of certain sorts are overwhelmingly good for the attitude taken. Statistical methods applied to lesser differences may disclose the existence of still further order in variation. I have not employed this method simply because other, more important problems with Cynipidæ demand our present attention, and are likely to do so for some time. The question of host relationships of cynipids is considerably cleared up by this treatment of varieties. It appears that some species show no constant variation (unless possibly discernible by statistical methods) when occurring upon different oaks in the same region, while other species have de veloped distinct varieties on each host. In this case the amount of host variation is usually less than that of geographic varieties, but sometimes it is more. In every case the varieties of a single species are confined to either white or to black oaks, altho closely related species may occur on oaks of both groups. Many undescribed varieties have been previously overlooked because of a charming lack of knowledge of faunal areas and possible factors of distribution. It would be the rankest sort of farce to delimit faunal areas on the basis of the published records of distribution of Cynipidæ, based on determinations which neglect varietal differences! We have yet to learn that some of the distribution work has no better foundation than such careless taxonomy. It now appears that each variety is restricted to a limited, more or less continuous geographic area; in no case does a single variety extend over more than one faunal zone, and in only two or three of the Cynipidæ I have studied does more than a single variety of one species occur in a single faunal area. These areas I have of necessity in part defined by studying Cynipidæ themselves, when the several species of a region prove to agree most remarkably in the extent of their range. A consideration of the ranges of other organisms has been of some help in these interpretations, but there is not much trustworthy literature available. For the Pacific Coast good work on oaks has been done by Jepson (1910, Mem. Univ. Calif., II, pp. 202-241), and there is a remarkable study of the distribution of beetles by Van Dyke (1919, Ann. Ent. Soc. Amer., XII, pp. 1-12). My studies of Cynipidæ very largely bear out Van Dyke's conclusions as far as we have covered the same fields. Undoubtedly many factors have contributed in limiting the distribution of cynipid species. Host distributions do not appear to have had much if any positive influence, altho acting negatively to some extent, as when oaks are entirely absent from a region. I must admit some prejudice for believing that the past geologic history of an area is the most potent factor in present distributions. The newer country, geologically, appears to possess the newer varieties. All of these questions I shall consider in detail after a further study of Cynipidæ. The genera of Cynipidæ have always needed revision, and the introduction of two terms new to American literature is |