160 
SEXUAL selection: birds. 
Part II. 
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 diflScult. The 
more probable result of the long-continued destruction 
of the more brightly-coloured females, supposing the 
equal form of transmission to prevail, would be the les- 
sening or annihilation of the bright colours of the males, 
owing to their continually crossing with the duller 
females. It would be tedious to follow out all the 
other possible results ; but I may remind the reader, as 
shewn in the eighth chapter, that if sexually-limited 
variations in brightness occurred in the females, even if 
they were not in the least injurious to them and con- 
sequently were not eliminated, yet they wwld not be 
favoured or selected, for the male usually accepts any 
female, and does not select the more attractive indi- 
viduals ; consequently these variations would be liable 
to be lost, and would have little influence on the 
character of the race ; and this will aid in account- 
ing for the females being commonly less brightly- 
coloured than the males. 
In the chapter just referred to, instances were given, 
and any number might have been added, of variations 
occurring at different ages, and inherited at the same 
age. It was also shewn that variations which occur late 
in life are commonly transmitted to the same sex in 
which they first appeared ; whilst variations occurring 
early in life are apt to be transmitted to both sexes ; 
not that all the cases of sexually-limited transmission 
can thus be accounted for. It was further shewn that 
if a male bird varied by becoming brighter whilst 
