The Descent of Man

[Fig. 62. Rhynchaea capensis (from Brehm).]
The females of the three species of Painted Snipes
(Rhynchaea, Fig. 62) "are not only larger
but much more richly coloured than the males."
(16. Jerdon, 'Birds of India,' vol. iii. p. 677.) With
all other birds in which the trachea differs in
structure in the two sexes it is more developed
and complex in the male than in the female; but
in the Rhynchaea australis it is simple in the
male, whilst in the female it makes four distinct
convolutions before entering the lungs. (17.
Gould's 'Handbook to the Birds of Australia,'
vol. ii. p. 275.) The female therefore of this species
has acquired an eminently masculine character.
Mr. Blyth ascertained, by examining
many specimens, that the trachea is not convoluted
in either sex of R. bengalensis, which species
resembles R. australis so closely, that it can
hardly be distinguished except by its shorter
toes. This fact is another striking instance of the
law that secondary sexual characters are often