XAXVIi, XXXviii] Gre 8) 
The late Professor A. T. Packard read a paper before the 
American Philosophical Society on December 2nd, 1904, in 
which he criticised at some length the Bates-Miiller hypothesis 
of mimicry. The paper is the more welcome owing to the 
comparative scarcity of literature dealing with the subject 
from an antagonistic point of view. Since the promulgation 
of the presently accepted theories of mimicry and protective 
resemblance the subject has made very considerable progress. 
Whilst, however, the strongest supporters of the Bates- 
Miiller theories have lost no opportunity of publishing facts 
corroborative of the general principles which they uphold, 
the opponents of these views have for the most part contented 
themselves with a kind of passive disagreement, usually 
treating the whole subject with a species of airy contempt, 
sometimes putting forward somewhat vaguely formulated ob- 
jections, but in no case, so far as I have been able to ascertain, 
bringing forward any really satisfactory hypothesis on which 
to base an explanation of those phenomena for which the 
Bates-Miiller theories seek to account. Nor does the paper in 
question remove this latter defect. The main conclusion is 
that the instances of resemblance which have been noted 
amongst organisms are due, not to any tendency of an un- 
protected species to resemble for its own benefit, a protected 
form, but to the biological environment of the species con- 
cerned. ‘‘Sunlight or excessive contrasts of light and shade 
combined, moisture and dryness, differences in environment or 
other climatic causes as affecting the amount and distribution 
of pigment.” It is as a student of the so-called mimicry in 
butterflies endeavouring to be as impartial as a deep interest 
in the subject will allow, that I wish to deal with Professor 
Packard’s paper, and the object of the following remarks is to 
show that the difficulties in the way of accepting that author’s 
arguments against the Bates-Miiller theories are at least as 
great as those which beset their would-be upholders, and 
that whilst the paper is deserving of the greatest attention 
as being one of the few lengthy and carefully compiled 
criticisms of what Dr. Sharp describes as the “fashionable 
theories,” it at the same time falls short of the one essential 
of providing a really satisfactory alternative. 
