harmonious
work is so very severe as necessarily to stimulate his imitative genius.
Birds are for ever hunting him down among the green leaves, and only
those caterpillars which effectually deceive them by their admirable
imitations can ever hope to survive and become the butterflies who hand
on their larval peculiarities to after ages. Need I add that the
variations are, of course, unconscious, and that accident in the first
place is ultimately answerable for each fresh step in the direction of
still closer simulation?

The geometric moths have brown caterpillars, which generally stand erect
when at rest on the branches of trees and so resemble small twigs; and,
in order that the resemblance may be the more striking, they are often
covered with tiny warts which look like buds or knots upon the surface.
The larva of that familiar and much-dreaded insect, the death's-head
hawk-moth, feeds as a rule on the foliage of the potato, and its very
varied colouring, as Sir John Lubbock has pointed out, so beautifully
harmonises with the brown of the earth, the yellow and green of the
leaves, and the faint purplish blue of the lurid flowers, that it can
only be distinguished when the eye happens accidentally to focus itself
exactly upon the spot occupied by the unobtrusive caterpillar. Other
larvae which frequent pine trees have their bodies covered with tufts of
green hairs that serve to imitate the peculiar pine foliage. One queer
little caterpillar, which lives upon the hoary foliage of the
sea-buckthorn, has a grey-green body, just like the buckthorn leaves,
relieved by a very conspicuous red spot which really represents in size
and colour one of the berries that grow around it. Finally the larva of
the elephant hawk-moth, which grows to a very large size, has a pair of
huge spots that seem like great eyes; and direct experiment establishes
the fact that small birds mistake it for a young snake, and stand in
terrible awe of it accordingly, though it is in reality a perfectly
harmless insect, and also, as I am credibly informed (for I cannot speak
upon the point from personal experience), a very tasty and
well-flavoured insect, and 'quite good to eat' too, says an eminent
authority. One of these big snake-like caterpillars once frightened Mr.
Bates himself on the banks of the Amazon.

Now, I know that cantankerous person, the universal objector, has all
along been bursting to interrupt me and declare that he himself
frequent