The Descent of Man

sexes, though arising and perfected in one sex
alone.
On the whole, although many serious objections
may be urged, it seems probable that most
of the brilliantly-coloured species of Lepidoptera
owe their colours to sexual selection, excepting
in certain cases, presently to be mentioned,
in which conspicuous colours have been gained
through mimicry as a protection. From the ardour
of the male throughout the animal kingdom,
he is generally willing to accept any female;
and it is the female which usually exerts a
choice. Hence, if sexual selection has been efficient
with the Lepidoptera, the male, when the
sexes differ, ought to be the more brilliantly
coloured, and this undoubtedly is the case.
When both sexes are brilliantly coloured and
resemble each other, the characters acquired by
the males appear to have been transmitted to
both. We are led to this conclusion by cases,
even within the same genus, of gradation from