Kinsey : Gall Wasp Genus Cynips 
23 
coast we were dealing with pezomachoides, which is another 
species. At first the population was a mixture of insects of 
erinacei and pezomachoides and hybrids between, and it was 
only near the ocean that we found pure colonies of this new 
species, altho the typically smooth gall of pezomachoides was 
dominant to the western limits of the influence of the insect. 
But pezomachoides, altho very similar to erinacei, varies 
within limits that are different from those of erinacei. We 
shall find pezomachoides wherever we collect, until some day 
we turn in from the coast toward the heart of Georgia and 
meet a larger form of naked gall which will be derivatus; 
and then when we cross the southern front of the Blue Ridge 
and go into the Cumberlands we shall find the insect called 
advena, and in Kentucky it will be ozark, and in southern 
Indiana it will be erinacei again. In each area we shall find 
a population obviously related to every other, but each will 
constitute a population whose limits of variation are different 
from those of any other. Sometimes these limits overlap, 
sometimes they are wholly within, sometimes they are wholly 
without the limits for each other species. Sometimes the 
populations are wholly segregated by mountain crests and 
divides, sometimes the populations hybridize and intergrade 
over broad zones of transition ; but always each population is 
distinct in a great area which is the heart of the range of 
each species. This is the picture which has gradually de- 
veloped over the 32,000 miles, thru the 12 years during which 
we have pursued species. 
And now, one confusion needs explanation before we are 
finished with this part of our discussion. It must be pointed 
out that there is a biologic concept called species and a tax- 
onomic category called species, and that the two are not 
always synonymous. The concept we have developed is the 
biologic concept to which all except the taxonomists must refer 
whenever they consider the problem of species. This is the 
sense in which even taxonomists, including ourselves, intend 
the word when it is used in most biologic connections. But 
this biologic species is, unfortunately, the first of the tax- 
onomic categories, the fundamental unit with taxonomic sig- 
nificance. As a category taxonomists may label this a geo- 
graphic variant, a variety, a subspecies, or a species. There 
