ngs 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 Muller. 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: "I am often in despair in making the generality of NATURALISTS
even comprehend me. Intelligent men who are not naturalists and have not
a bigoted idea of the term species, show more clearness of mind." ("More
Letters", I. page 175.)

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." ("Life and
Letters" II. page 245.)

Mimicry was not only one of the first great departments of zoological
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.

MIMICRY AND SEX.

Ever since Wallace's classical memoir on mimicry in the Malayan
Swallowtail butterflies, those naturalists who have written on the
subject have followed his interpretation of the marked prevalence of
mimetic resembla