The Descent of Man

would be indistinguishable from the males; and
this likewise occurs with many birds. If, however,
dull colours were of high importance for
the safety of the female during incubation, as
with many ground birds, the females which
varied in brightness, or which received through
inheritance from the males any marked accession
of brightness, would sooner or later be
destroyed. But the tendency in the males to
continue for an indefinite period transmitting
to their female offspring their own brightness,
would have to be eliminated by a change in the
form of inheritance; and this, as shewn by our
previous illustration, would be extremely difficult.
The more probable result of the longcontinued
destruction of the more brightlycoloured
females, supposing the equal form of
transmission to prevail, would be the lessening
or annihilation of the bright colours of the males,
owing to their continual crossing with the
duller females. It would be tedious to follow
out all the other possible results; but I may re-