€hap. XI. 
BUTTERFLIES AND MOTHS. 
415 
that the females alone in this latter as in the previous 
cases originally varied in certain characters ; these cha- 
racters having been preserved and augmented through 
ordinary selection for the sake of protection and from 
the first transmitted to the female offspring alone. 
Bright Colours of Caterpillars . — Whilst reflecting on 
the beauty of many butterflies, it occurred to me that 
some caterpillars were splendidly coloured, and as 
sexual selection could not possibly have here acted, 
it appeared rash to attribute the beauty of the mature 
insect to this agency, unless the bright colours of their 
larvae could be in some manner explained. In the first 
place it may be observed that the colours of caterpillars 
do not stand in any close correlation with those of the 
mature insect. Secondly, their bright colours do not 
the aid of selection to check the variations being inherited by the 
other sex. No doubt if it could be shewn that the females of very 
many species had been rendered beautiful through protective mimickry, 
but that this has never occurred with the males, it would be a serious 
difficulty. But the number of cases as yet known hardly suffices for a 
fair judgment. We can see that the males, from having the power of 
flying more swiftly, and thus escaping danger, would not be so likely 
as the females to have had their colours modified for the sake of protec- 
tion ; but this would not in the least have interfered with their receiving 
protective colours through inheritance from the females. In the second 
place, it is probable that sexual selection would actually tend to prevent 
a beautiful male from becoming obscure, for the less brilliant individuals 
would be less attractive to the females. Supposing that the beauty of 
the male of any species had been mainly acquired through sexual 
selection, yet if this beauty likewise served as a protection, the acquisi- 
tion would have been aided by natural selection. But it would be 
quite beyond our power to distinguish between the two processes of 
sexual and ordinary selection. Hence it is not likely that we should 
be able to adduce cases of the males having been rendered brilliant 
exclusively through protective mimickry, though this is comparatively 
easy with the females, which have rarely or never been rendered beau- 
tiful, as far as we can judge, for the sake of sexual attraction, although 
they have often received beauty through inheritance from their male 
parents. 
