lar resemblance to
twigs and branches. Some of these are a foot long and as thick as one's
finger, and their whole colouring, form, rugosity, and the arrangement
of the head, legs, and antennae, 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 most minute
examination that I could convince myself it was not so.

We need not adduce any more examples to show how important are the
details of form and of colouring in animals, and that their very
existence may often depend upon their being by these means concealed
from their enemies. This kind of protection is found apparently in every
class and order, for it has been noticed wherever we can obtain
sufficient knowledge of the details of an animal's life-history. It
varies in degree, from the mere absence of conspicuous colour or a
general harmony with the prevailing tints of nature, up to such a minute
and detailed resemblance to inorganic or vegetable structures as to
realize the talisman of the fairy tale, and to give its possessor the
power of rendering itself invisible.

_Theory of Protective Colouring._

We will now endeavour to show how these wonderful resemblances have most
probably been brought about. Returning to the higher animals, let us
consider the remarkable fact of the rarity of white colouring in the
mammalia or birds of the temperate or tropical zones in a state of
nature. There is not a single white land-bird or quadruped in Europe,
except the few arctic or alpine species, to which white is a protective
colour. Yet in many of these creatures there seems to be no inherent
tendency to avoid white, for directly they are domesticated white
varieties arise, and appear to thrive as well as others. We have white
mice and rats, white cats, horses, dogs, and cattle, white poultry,
pigeons, turkeys, and ducks, and white rabbits. Some of these animals
have been domesticated for a long period, others only for a few
centuries; but in alm