I shall not refer them to Dr.
Weismann's original treatise, as well translated and still further
enlarged by Mr. Raphael Meldola, but will present them instead with a
brief _resume_, boiled down and condensed into a patent royal elixir of
learning. Your caterpillar, then, runs many serious risks in early life
from the annoying persistence of sundry evil-disposed birds, who insist
at inconvenient times in picking him off the leaves of gooseberry bushes
and other his chosen places of residence. His infant mortality, indeed,
is something simply appalling, and it is only by laying the eggs that
produce him in enormous quantities that his fond mother the butterfly
ever succeeds in rearing on an average two of her brood to replace the
imago generation just departed. Accordingly, the caterpillar has been
forced by adverse circumstances to assume the most ridiculous and
impossible disguises, appearing now in the shape of a leaf or stem, now
as a bundle of dark-green pine needles, and now again as a bud or
flower, all for the innocent purpose of concealing his whereabouts from
the inquisitive gaze of the birds his enemies.

When the caterpillar lives on a plant like a grass, the ribs or veins of
which run up and down longitudinally, he is usually striped or streaked
with darker lines in the same direction as those on his native foliage.
When, on the contrary, he lives upon broader leaves, provided with a
midrib and branching veins, his stripes and streaks (not to be out of
the fashion) run transversely and obliquely, at exactly the same angle
as those of his wonted food-plant. Very often, if you take a green
caterpillar of this sort away from his natural surroundings, you will be
surprised at the conspicuousness of his pale lilac or mauve markings;
surely, you will think to yourself, such very distinct variegation as
that must betray him instantly to his watchful enemies. But no; if you
replace him gently where you first found him, you will see that the
lines exactly harmonise with the joints and shading of his native leaf:
they are delicate representations of the soft shadow cast by a rib or
vein, and the local colour is precisely what a painter would have had to
use in order to produce the corresponding effect. The shadow of
yellowish green is, of course, always purplish or lilac. It may at first
sight seem surprising that a caterpillar should possess so much artistic
sense and dexterity; but then the penalty for bungling or in