e unhesitatingly
assumed that all its characters had been slowly acquired through
natural selection; namely, by individuals having been born with slight
profitable modifications, which were inherited by the offspring, and
that these again varied and again were selected, and so onwards. But
with the working ant we have an insect differing greatly from its
parents, yet absolutely sterile; so that it could never have transmitted
successively acquired modifications of structure or instinct to its
progeny. It may well be asked how it is possible to reconcile this case
with the theory of natural selection?

First, let it be remembered that we have innumerable instances, both in
our domestic productions and in those in a state of nature, of all sorts
of differences of inherited structure which are correlated with certain
ages and with either sex. We have differences correlated not only with
one sex, but with that short period when the reproductive system is
active, as in the nuptial plumage of many birds, and in the hooked jaws
of the male salmon. We have even slight differences in the horns of
different breeds of cattle in relation to an artificially imperfect
state of the male sex; for oxen of certain breeds have longer horns than
the oxen of other breeds, relatively to the length of the horns in
both the bulls and cows of these same breeds. Hence, I can see no
great difficulty in any character becoming correlated with the sterile
condition of certain members of insect communities; the difficulty lies
in understanding how such correlated modifications of structure could
have been slowly accumulated by natural selection.

This difficulty, though appearing insuperable, is lessened, or, as I
believe, disappears, when it is remembered that selection may be applied
to the family, as well as to the individual, and may thus gain the
desired end. Breeders of cattle wish the flesh and fat to be well
marbled together. An animal thus characterized has been slaughtered,
but the breeder has gone with confidence to the same stock and has
succeeded. Such faith may be placed in the power of selection that a
breed of cattle, always yielding oxen with extraordinarily long horns,
could, it is probable, be formed by carefully watching which individual
bulls and cows, when matched, produced oxen with the longest horns; and
yet no one ox would ever have propagated its kind. Here is a better and
real illustration: According to M. Verlot, some var