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Wallace, Alfred Russel, 1823-1913

"Darwinism (1889)"

" Even such a huge animal as the giraffe is
said to be perfectly concealed by its colour and form when standing
among the dead and broken trees that so often occur on the outskirts of
the thickets where it feeds. The large blotch-like spots on the skin and
the strange shape of the head and horns, like broken branches, so tend
to its concealment that even the keen-eyed natives have been known to
mistake trees for giraffes or giraffes for trees.
Innumerable examples of this kind of protective colouring occur among
insects; beetles mottled like the bark of trees or resembling the sand
or rock or moss on which they live, with green caterpillars of the exact
general tints of the foliage they feed on; but there are also many cases
of detailed imitation of particular objects by insects that must be
briefly described.[69]

_Protective Imitation of Particular Objects._
The insects which present this kind of imitation most perfectly are the
Phasmidae, or stick and leaf insects. The well-known leaf-insects of
Ceylon and of Java, species of Phyllium, are so wonderfully coloured and
veined, with leafy expansions on the legs and thorax, that not one
person in ten can see them when resting on the food-plant close beneath
their eyes.


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