453 
1878.] Doctrine of Development. 
extent, in the egg and larva state. Unless the eggs and larvae 
which escaped to produce the next generation were those 
which would produce the more highly-coloured butterflies, 
it is difficult to perceive how the slight preponderance of 
colour sometimes selected by, the females should not be 
wholly neutralised by the extremely rigid selection for 
other qualities to which the offspring in every stage are 
exposed.” 
The above considerations, we submit, fully warrant natu- 
ralists, if not in the utter rejection of conscious Sexual 
Selection, at any rate in placing it in a kind of suspended 
position, to be condemned except some unexpected piece of 
evidence should be brought to light in its favour. 
But we may venture farther, calling especial attention to 
the words we have italicised. No one who has made ob- 
servations with even moderate care, upon any department 
of the animal kingdom, can doubt the sharpness of the 
struggle for existence, or can deny that of the eggs depo- 
sited by a female butterfly but a very small fraction ever 
come to maturity. Many no doubt, as Mr. Wallace states, 
perish as such without ever seeing the light at all. But 
how is this effected ? Every egg of the whole brood is 
equally and similarly helpless in case of the approach of a 
devourer or a parasite. None of them can escape by dint 
of any strength, swiftness, or cunning which it may possess 
in excess of the rest. Without absolutely saying that no 
variation can ever be traced among the eggs laid by one 
mother, we are warranted in declaring that any difference, 
either in colour, shape, odour, or other properties, which 
may cause egg a to be less easily perceived, or when per- 
ceived by an enemy to be more readily rejected, than eggs 
b, c, and d must be exceedingly trifling, and that the immu- 
nity thus gained must be regarded as a mere vanishing 
quantity. For one that escapes in virtue of such properties 
ten will owe their survival to what — humanly speaking — - 
must be pronounced mere chance. One egg, without pos- 
sessing any attribute of superiority or greater fitness, may 
have been deposited by its mother in a less conspicuous 
place than the rest. One egg may have perished, not from 
any comparative imperfection or want of fitness on its part, 
but because some ovivorous or parasitical insect chanced to 
pass over the particular leaf to which it was attached. 
Numbers of other causes might be mentioned — as far as we 
can judge perfectly accidental— upon which the quickening 
or the death of an egg may depend. Here, therefore, is no 
selection, no weeding out, but a destruction of one portion 
