The Descent of Man

In the same manner as bright colours have often
been partially transferred from the males to
the females, so it has been with the extraordinary
horns of many Lamellicorn and some other
beetles. So again, the sound-producing organs
proper to the males of the Homoptera and Orthoptera
have generally been transferred in a
rudimentary, or even in a nearly perfect condition,
to the females; yet not sufficiently perfect
to be of any use. It is also an interesting fact, as
bearing on sexual selection, that the stridulating
organs of certain male Orthoptera are not
fully developed until the last moult; and that
the colours of certain male dragon-flies are not
fully developed until some little time after their
emergence from the pupal state, and when they
are ready to breed.
Sexual selection implies that the more attractive
individuals are preferred by the opposite sex;
and as with insects, when the sexes differ, it is
the male which, with some rare exceptions, is