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Indiana University Studies 
States that they are in part responsible for the widespread 
opinion that there are no species but highly variable com- 
plexes ranging over this part of this country. This opinion 
is not justified by our study of Cynipidae. In series of re- 
lated 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 popula- 
tion, another transition population, and so on across the coun- 
try. 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 popu- 
lations 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 phylo- 
genetic 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 orig- 
inating 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 pezo- 
machoides pezomachoides vs. the range of Cynips mellea Caro- 
lina). 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 phylo- 
genetic 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. 
