The Descent of Man

in equally well-concealed spots, but in the one
species the sexes differ greatly, and in the other
very little.
Notwithstanding the foregoing objections, I
cannot doubt, after reading Mr. Wallace's excellent
essay, that looking to the birds of the
world, a large majority of the species in which
the females are conspicuously coloured (and in
this case the males with rare exceptions are
equally conspicuous), build concealed nests for
the sake of protection. Mr. Wallace enumerates
(19. 'Journal of Travel,' edited by A. Murray,
vol. i. p. 78.) a long series of groups in which
this rule holds good; but it will suffice here to
give, as instances, the more familiar groups of
kingfishers, toucans, trogons, puff-birds (Capitonidae),
plantain-eaters (Musophagae, woodpeckers,
and parrots. Mr. Wallace believes that
in these groups, as the males gradually acquired
through sexual selection their brilliant colours,
these were transferred to the females and