In some species the more beautiful males appear to have been selected
by the females; and in others the more beautiful females by the males.
Consequently in certain genera (Muller, p. 42), the males of the
several species differ much in appearance, whilst the females are
almost indistinguishable; in other genera the reverse occurs. H. Muller
believes (p. 82) that the colours gained by one sex through sexual
selection have often been transferred in a variable degree to the other
sex, just as the pollen-collecting apparatus of the female has often
been transferred to the male, to whom it is absolutely useless. (61. M.
Perrier in his article la Selection sexuelle d apres Darwin ( Revue
Scientifique, Feb. 1873, p. 868), without apparently having reflected
much on the subject, objects that as the males of social bees are known
to be produced from unfertilised ova, they could not transmit new
characters to their male offspring. This is an extraordinary objection.
A female bee fertilised by a male, which presented some character
facilitating the union of the sexes, or rendering him more attractive
to the female, would lay eggs which would produce only females; but
these young females would next year produce males; and will it be
pretended that such males would not inherit the characters of their
male grandfathers? To take a case with ordinary animals as nearly
parallel as possible: if a female of any white quadruped or bird were
crossed by a male of a black breed, and the male and female offspring
were paired together, will it be pretended that the grandchildren would
not inherit a tendency to blackness from their male grandfather? The
acquirement of new characters by the sterile worker-bees is a much more
difficult case, but I have endeavoured to shew in my Origin of
Species, how these sterile beings are subjected to the power of
natural selection.)
Mutilla Europaea makes a stridulating noise; and according to Goureau
(62. Quoted by Westwood, Modern Classification of Insects, vol. ii.
p. 214.) both sexes have this power. He attributes the sound to the
friction of the third and preceding abdominal segments, and I find that
these surfaces are marked with very fine concentric ridges; but so is
the projecting thoracic collar into which the head articulates, and
this collar, when scratched with the point of a needle, emits the
proper sound. It is rather surprising that both sexes should have the
power of stridulating, as the male is winged and the female wingless.
It is notorious that Bees express certain emotions, as of anger, by the
tone of their humming; and according to H. Muller (p. 80), the males of
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