196 
SEXUAL selection: bieds. 
Part II. 
auritum and Phasianus Wallichii) the two 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, this 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 nidification, 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 inex- 
perienced, 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, but 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 
w^ould 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 phea- 
sants, would not have been dangerous, and if they ap- 
peared during early youth, would generally have been 
transmitted to both sexes. 
In addition to the effects of the partial transference 
of characters 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.^^ With the males any such 
See, on this subject, chap, xxiii. in the ‘Variation of Animals and 
Plants under Domestication.’ 
