ENTOMOLOGY. 
153 
entomologist may often render important services to the farmer 
and the gardener, and thus give a direct practical value to his 
studies. Nearly every production of the field or the garden is 
subject to the attacks of insects, which, in case of their inordinate 
increase, may easily cause very great damage to the crops, or 
oven destroy them altogether. In the face of such enemies the 
cultivator is often quite helpless, and not unfrequently mistakes 
his friends for his foes, attributing the mischief produced by 
concealed enemies to more prominent forms, which are really 
doing their best for his benefit. In such cases the entomologist 
may step in to the assistance of his neighbour, indicate to him 
the real cause of the damage, and in many instances the best 
remedy, and the best time to employ it. 
The asserted influence of insect agency upon the forms and 
colours of flowers, referred to above, leads to other considerations 
which may serve to give additional importance to the study of 
ontomology. For while it is believed that plants and flowers are 
modified by the unconscious influence of insects, it is, on the 
other hand, at least equally certain that the insects will undergo 
modifications in their turn ; and there seems to be some reason to 
believe that the great and burning question as to the origin of 
species, or distinct forms of animals and plants, by evolution — 
that is to say, the modification of organisms under the influence 
of external causes, assisted by the survival of those best adapted 
to the prevailing conditions — will finally be fought out upon 
entomological grounds. In this respect the careful observation 
and comparison of the insect-faunas of scattered islands of 
common origin cannot but lead to most interesting results ; as 
may, indeed, be seen from the brilliant researches of Mr. Wallace 
upon the butterflies of certain islands in the Eastern Archipelago, 
and from the elaborate investigations of the late Mr. Vernon 
Wollaston upon the beetles of the Atlantic islands. In the case 
of the Cape Verde islands the last-mentioned distinguished ento- 
mologist, although a staunch anti-evolutionist, was compelled to 
admit that he did not believe all the closely related permanent 
forms which he felt himself compelled to describe as species 
really owed their existence to distinct acts of creation. 
One of the most curious phenomena the full recognition of 
which we owe to the promulgation of the doctrine of evolution 
is the mimicry or imitation by one organism of the general 
characters of another, or of some inanimate object, instances 
of which are tolerably numerous. Here again insects hold the 
first place. The subject was first approached in a philosophical 
manner by Mr. Bates, who found in the Valley of the Amazon 
whole groups of butterflies which imitated most closely the form 
and coloration of other species belonging to quite a distinct sub- 
family. Mr. Bates discovered that the imitated forms were 
