But of late years these cases have been greatly increased both in number
and variety, especially in regard to those which closely imitate special
objects among which they live; and there are other kinds of coloration
which long appeared to have no use. Large numbers of animals, more
especially insects, are gaudily coloured, either with vivid hues or with
striking patterns, so as to be very easily seen. Now it has been found,
that in almost all these cases the creatures possess some special
quality which prevents their being attacked by the enemies of their kind
whenever the peculiarity is known; and the brilliant or conspicuous
colours or markings serve as a warning or signal flag against attack.
Large numbers of insects thus coloured are nauseous and inedible;
others, like wasps and bees, have stings; others are too hard to be
eaten by small birds; while snakes with poisonous fangs often have some
characteristic either of rattle, hood, or unusual colour, which
indicates that they had better be left alone.
But there is yet another form of coloration, which consists in special
markings--bands, spots, or patches of white, or of bright colour, which
vary in every species, and are often concealed when the creature is at
rest but displayed when in motion,--as in the case of the bands and
spots so frequent on the wings and tails of birds.
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