Page:The Gall Wasp Genus Cynips.pdf/60

 States that they are in part responsible for the widespread opinion that there are no species but highly variable complexes ranging over this part of this country. This opinion is not justified by our study of Cynipidae. In series of related species, east of the Rockies (figs. 37, 50, 59, 63, and 70), we do not find continuous gradations from one to the other end of the group, but first an area with a pure population, then an area of hybrid individuals, then another pure population, another transition population, and so on across the country. The ornithologists have ruled that the term species should be restricted to populations between which there are no intergradent individuals, and the term subspecies to populations between which such intergrades do exist. They imply that the presence or absence of hybrid individuals in the transition zones is a matter of phylogenetic significance. With this I cannot agree. To follow this rule, the ultimate phylogenetic unit (the species concept of biologists in general, the result of the most recent mutation which has been sufficiently isolated to give rise to pure populations) would usually rank as a species in the Far West. In the East populations originating in precisely the same way and representing the very same stage in phylogeny would be called subspecies.

5. The range of each species of Cynips coincides to a large degree with the range of every other species of Cynips of that part of the country. The maps thruout this paper will show the location of such concommitant ranges. These areas bear some resemblance to the life zones of current repute, but the ranges of no two species are precisely the same, and there are outstanding discrepancies (e.g. the range of Cynips pezomachoides pezomachoides vs. the range of Cynips mellea Carolina). These generalized areas certainly bear no relation to the life zones hypothesized by C. Hart Merriam (1898) and since then propagated by the U.S. Biological Survey.

6. The data given in a later section of this paper on the phylogenetic history of Cynips, and summarized in our phylogenetic maps (figures 8-13) suggest that the location and shape of these generalized areas of distribution are in part a result of the place of origin and path of migration of each subgenus. If this is so, the picture may be different for each group of organisms, and it becomes doubtful how far these approximations to life zones in Cynips may be extended to other groups of organisms.