The Descent of Man

the wing-covers of the female Achetidae, and
on the femora of the female Acridiidae. In the
Homoptera, also, the females have the proper
musical apparatus in a functionless state; and
we shall hereafter meet in other divisions of the
animal kingdom with many instances of structures
proper to the male being present in a rudimentary
condition of the female.
Landois has observed another important fact,
namely, that in the females of the Acridiidae,
the stridulating teeth on the femora remain
throughout life in the same condition in which
they first appear during the larval state in both
sexes. In the males, on the other hand, they
become further developed, and acquire their
perfect structure at the last moult, when the
insect is mature and ready to breed.
From the facts now given, we see that the
means by which the males of the Orthoptera
produce their sounds are extremely diversified,
and are altogether different from those emplo-