The Descent of Man

the Coleoptera, however, as before remarked, it
is in the great Lamellicorn group, placed by
some authors at the head of the Order, and in
which we sometimes see a mutual attachment
between the sexes, that we find the males of
some species possessing weapons for sexual
strife, others furnished with wonderful horns,
many with stridulating organs, and others ornamented
with splendid metallic tints. Hence it
seems probable that all these characters have
been gained through the same means, namely
sexual selection. With butterflies we have the
best evidence, as the males sometimes take
pains to display their beautiful colours; and we
cannot believe that they would act thus, unless
the display was of use to them in their courtship.
When we treat of Birds, we shall see that they
present in their secondary sexual characters the
closest analogy with insects. Thus, many male
birds are highly pugnacious, and some are fur-