Mimicry 291 
mimicry did not also record that the characteristics which distinguish 
the northern from the southern individuals of the African species 
correspond with the presence, in the north but not in the south, 
of certain entirely different butterflies. That this additional informa- 
tion should so greatly weaken, in certain minds, the appeal of a 
favourite study, is a psychological problem of no little interest. 
This curious antagonism is I believe confined to a few students of 
insects. Those naturalists who, standing rather farther off, are able 
to see the bearings of the subject more clearly, will usually admit the 
general support yielded by an ever-growing mass of observations 
to the theories of Mimicry propounded by H. W. Bates and Fritz 
Miiller. In like manner natural selection itself was in the early days 
often best understood and most readily accepted by those who were 
not naturalists. Thus Darwin wrote to D. T. Ansted, Oct. 27, 1860: 
“T am often in despair in making the generality of natwralists even 
comprehend me. Intelligent men who are not naturalists and have 
not a bigoted idea of the term species, show more clearness of 
mind'.” 
Even before the Origin appeared Darwin anticipated the first 
results upon the mind of naturalists. He wrote to Asa Gray, Dec. 21, 
1859: “I have made up my mind to be well abused; but I think it of 
importance that my notions should be read by intelligent men, 
accustomed to scientific argument, though not naturalists. It may 
seem absurd, but I think such men will drag after them those 
naturalists who have too firmly fixed in their heads that a species 
is an entity?” 
Mimicry was not only one of the first great departments of zoo- 
logical knowledge to be studied under the inspiration of Natural 
Selection, it is still and will always remain one of the most interesting 
and important of subjects in relation to this theory as well as to 
evolution. In mimicry we investigate the effect of environment in its 
simplest form: we trace the effects of the pattern of a single species 
upon that of another far removed from it in the scale of classification. 
When there is reason to believe that the model is an invader from 
another region and has only recently become an element in the 
environment of the species native to its second home, the problem 
gains a special interest and fascination. Although we are chiefly 
dealing with the fleeting and changeable element of colour we expect 
to find and we do find evidence of a comparatively rapid evolution. 
The invasion of a fresh model is for certain species an unusually 
sudden change in the forces of the environment and in some instances 
we have grounds for the belief that the mimetic response has not 
been long delayed. 
1 More Letters, 1, p. 175. 2 Life and Letters, 11. p. 245. 
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