154 
POPULAR SCIENCE REVIEW, 
endowed with certain properties which rendered them disagree- 
able to insectivorous birds, and hence concluded that these 
mimetic resemblances in general were acquired by a process of 
selection for protective purposes. Many other instances of the 
same kind have since been detected in various parts of the world, 
and they are by no means deficient even in this country. 
In the preceding rapid and very imperfect sketch I have en- 
deavoured to indicate the more important of the manifold 
pleasures and advantages which the study of entomology offers to 
its votaries, even supposing them to pursue it as a mere amuse- 
ment. But even in connection with this method of study it has 
been pointed out that certain philosophical notions will crop up, 
such as the homology of the parts of the mouth in biting and 
sucking insects, the phenomena of the metamorphoses and of 
parasitism, the close inter-relation of diverse organisms, and the 
question of the origin of species. The influence of such studies 
in training the mind to habits of observation such as involve the 
clear appreciation of evidence has also been mentioned as a great 
and important educational advantage. 
There is yet another side to the question. In these days of 
competitive and other examinations, and of wide-spread science- 
teaching, great numbers of students learn more or less of what 
is called zoology from lectures and text-books, their object being 
in most cases, perhaps, only to pass what they call an “ exam.” 
By this means a certain amount of morphological knowledge gets 
crammed into their heads, but of the practical application of 
this they are as innocent as the babe unborn. For the due com- 
prehension even of the principles of zoology it is essential that 
the student should possess something more than a mere book- 
knowledge, often merely of structural details ; and an acquaint- 
ance with those principles is becoming day by day more neces- 
sary, as natural-history considerations are assuming a more and 
more prominent position in our general philosophy. How is 
this to be attained ? It is manifestly impossible for anyone 
who does not devote himself entirely to zoological pursuits to 
make himself practically acquainted with the whole animal 
kingdom ; he must perforce confine his attention more or less to 
some special group, and extend the knowledge of the principles 
and method of zoology thus acquired to the formation of a 
general conception of the whole. I have already indicated that, 
from the ease with which it is followed, and the total absence of 
restriction as to locality, the study of entomology presents special 
advantages ; and in other respects, if pursued in no contracted 
spirit, its influence on the mind of the student will be at least 
equally beneficial with that of any other branch of natural 
history. 
