( Piii ) 
able. But there can be no dispute as to the high import¬ 
ance and interest of the facts that he has brought together, 
and I trust that the examples I have given may induce 
entomologists who are interested in the study of evolution, 
and by whom these researches may hitherto have been over¬ 
looked, to make themselves acquainted with this mine of 
valuable information. They may not find themselves able to 
agree with the author at all points, but they will be intro¬ 
duced to a great mass of material with an important beax'ing 
on the nature and causes of variation, the working of 
heredity, the efficacy of selection, the significance of warning 
colours, and many other matters essential to a proper 
comprehension of the problem of evolution. 
There is one other phase of this great problem about which 
I should like to say a few words, because here again our 
special entomological studies have an important part to play. 
They have already contributed much towards the comprehen¬ 
sion of this side of the question, and I am convinced that they 
are capable of leading to a still further advancement of know¬ 
ledge in the same direction. I refer to the psychic aspect of 
evolution. 
It was fully recognised by Darwin himself that mental no 
less than physical characters are subject to evolution. The 
same principle was adopted by Wallace, not, it is true, with¬ 
out reservation, and received at his hands,-some interesting 
developments. But to Professor Mark Baldwin belongs the 
principal credit of insisting on and driving home the fact that 
evolution is psychophysical; that, as he puts it, “there are not 
two evolutions, one ‘ organic ’ and the other ‘ mental,’ but that 
mind and body have evolved by one process and in one series 
of graduated stages.” Now in order to illustrate in a forcible 
manner the interdependence of physical and psychic pheno¬ 
mena in evolution, he has recourse to the theory of warning 
colours in insects. This he expands in the following manner: 
“ As preliminary to the theory there is the fact o coloration, 
which is distinctly physical. The question is as to its origin. 
The theory holds it to be due to the warning given to other 
individuals that a particular colouring is distasteful or 
poisonous. Now in order that this warning be given, the 
