enormous extent in the egg, larva, and pupa states;
and perhaps not more than one in a hundred of the eggs laid produces a
perfect insect which lives to breed. Here, then, the impotence of female
selection, if it exist, must be complete; for, unless the most
brilliantly coloured males are those which produce the best protected
eggs, larvae, and pupae, and unless the particular eggs, larvae, and
pupae, which are able to survive, are those which produce the most
brilliantly coloured butterflies, any choice the female might make must
be completely swamped. If, on the other hand, there _is_ this
correlation between colour development and perfect adaptation to
conditions in all stages, then this development will necessarily proceed
by the agency of natural selection and the general laws which determine
the production of colour and of ornamental appendages.[135]

_General Laws of Animal Coloration._

The condensed account which has now been given of the phenomena of
colour in the animal world will sufficiently show the wonderful
complexity and extreme interest of the subject; while it affords an
admirable illustration of the importance of the great principle of
utility, and of the effect of the theories of natural selection and
development in giving a new interest to the most familiar facts of
nature. Much yet remains to be done, both in the observation of new
facts as to the relations between the colours of animals and their
habits or economy, and, more especially, in the elucidation of the laws
of growth which determine changes of colour in the various groups; but
so much is already known that we are able, with some confidence, to
formulate the general principles which have brought about all the beauty
and variety of colour which everywhere delight us in our contemplation
of animated nature. A brief statement of these principles will fitly
conclude our exposition of the subject.

1. Colour may be looked upon as a necessary result of the highly complex
chemical constitution of animal tissues and fluids. The blood, the bile,
the bones, the fat, and other tissues have characteristic, and often
brilliant colours, which we cannot suppose to have been determined for
any special purpose, as colours, since they are usually concealed. The
external organs, with their various appendages and integuments, would,
by the same general laws, naturally give rise to a greater variety of
colour.

2. We find it to be the fact that colour