Contributions to the theory of natural selection. A series of essays ... By Alfred Russel Wallace ...

64 MIMICRY, AND OTHER PROTECTIVE
tropical Muantid(e and Locustidle are of the exact tint of
the leaves on which they habitually repose, and many
of them in addition have the veinings of their wings
modified so as exactly to imitate that of a leaf. This
is carried to the furthest possible extent in the wonderful genus, Phyllium, the " walking leaf," in which not
only are the wings perfect imitations of leaves in every
detail, but the thorax and legs are flat, dilated, and
leaf-like; so that when the living insect is resting
among the foliage on which it feeds, the closest observation is often unable to distinguish between the
animal and the vegetable.
The whole family of the Phasmidoe, or spectres, to
which this insect belongs, is more or less imitative, and
a great number of the species are called " walking-stick
insects," from their singular resemblance to twigs and
branches. Some of these are a foot long and as thick
as one's finger, and their whole colonring, form, rugosity, and the arrangement of the head, legs, and antenme, are such as to render them absolutely identical in
appearance with dead sticks. They hang loosely about
shrubs in the forest, and have the extraordinary habit
of stretching out their legs unsymmetrically, so as to
render the deception more complete. One of these
creatures obtained by myself in Borneo (Ceroxylus
laceratus) was covered over with foliaceous excrescences
of a clear olive green colour, so as exactly to resemble a
stick grown over by a creeping moss or jungermannia.
The Dyak who brought it me assured me it was grown
over with moss although alive, and it was only after a