4.72 The Descent of Man. Part 11. 



former and recent times. But it deserves especial attention that 

 brilliant colours have been transferred much more rarely than 

 other tints. For instance, the maie of the red-throated blue- 

 breast (Cyanecula suecica) has a rich blue breast, including a sub- 

 triangular red mark ; now marks of nearly the same shape have 

 been transferred to the female, but the central space is fulvous 

 instead of red, and is surrounded by mottled instead of blue 

 feathers. The Gallinaceae offer many analogous cases ; for none of 

 the species, such as partridges, quails, guinea-fowls, &c, in which 

 the colours of the j^lumage have been largely transferred from 

 the male to the female, are brilliantly coloured. This is well 

 exemplified with the pheasants, in which the male is generally 

 so much more brilliant than the female ; but with the Eared 

 and Cheer pheasants (Crossoptilon auritum and Phasianus vcal- 

 licltii) the sexes closely resemble each other and their colours are 

 dull. We may go so far as to believe that if any part of the 

 plumage in the males of these two pheasants had been brilliantly 

 coloured, it would not have been transferred to the females. 

 These facts strongly support Mr. Wallace's view that with birds 

 which are exposed to much danger during incubation, the 

 transference of bright colours from the male to the female has 

 been checked through natural selection. We must not, however, 

 forget that another explanation, before given, is possible ; namely, 

 that the males which varied and became bright, whilst they were 

 young and inexperienced, would have been exposed to much 

 danger, and would generally have been destroyed ; the older and 

 more cautious males, on the other hand, if they varied in a like 

 manner, would not only have been able to survive, Dut would 

 have been favoured in their rivalry with other males. Now 

 variations occurring late in life tend to be transmitted exclusively 

 to the same sex, so that in this case extremely bright tints would 

 not have been transmitted to the females. On the other hand, 

 ornaments of a less conspicuous kind, such as those possessed by 

 the Eared and Cheer pheasants, would not have been dangerous, 

 and if they appeared during early youth, would generally have 

 been transmitted to both sexes. 



In addition to the effects of the partial transference of charac- 

 ters from the males to the females, some of the differences 

 between the females of closely allied species may be attributed to 

 the direct or definite action of the conditions of life. 11 With the 

 males, any such action would generally have been masked by the 

 brilliant colours gained through sexual selection ; but not so 

 with the females. Each of the endless diversities in plumage, 



11 See, on this subject, ch:.p xjuii. in the ' Variation of Animals and 

 Plants under Domestication.' 



