18 
Indiana University Studies 
in nature; and such students as Bateson and Morgan have 
suggested that that application must be made by the taxon- 
omists if (it is implied) the taxonomists ever become con- 
vinced that there are realities in nature that deserve to be 
called species. 
Now, with these imputations of the unreality of species, I 
find myself no longer in accord. In the data that follow, 
evidence is presented that species are realities in nature more 
nearly satisfying the geneticist’s concepts than the conven- 
tions of current taxonomy, and that the origins of such species 
are more satisfactorily explained on hereditary bases than 
by philosophic theories that may be invoked in extenuation 
of the fact and the factors of organic evolution. 
We may begin our analysis of species by an examination of 
a few individuals taken in the field. We then become im- 
pressed with the truth of the assertion that no two individuals 
are exactly alike. And if we extend our investigations to 
several dozen individuals, we shall be confused by the varying 
characters that enter into any population which ordinarily 
passes as a species. 
But if, on the other hand, we extend our examination to 
several hundred such individuals, we shall become impressed 
with another opinion, namely that there are many more points 
of uniformity than of variation among individuals taken from 
a given locality and habitat. Perhaps a half-dozen characters 
will show appreciable variation, while the hundreds of other 
characters that go to make up an organism are remarkably 
constant. One may believe that if larger series were more 
often utilized in taxonomic work the current bewilderment 
over variation would give way to a renewed respect for a 
certain uniformity that exists thruout such groups of indi- 
viduals. 
Again, the variation that may be observed in characters 
that do vary occurs within narrow limits. Thus, the antennal 
count in species of Cynips often varies by one, but among 
many thousands of individuals none has shown two segments 
more or less than any other individual in that species. The 
length of the wings in relation to the length of the body of 
any cynipid is not altogether an invariable item, but among 
the many measurements I have made this wing-body ratio is 
always within three or four per cent of the mean for the 
