The Descent of Man

to the development of the caterpillars of Bombyx
cynthia and yamamai, and especially to
that of some dwarfed caterpillars reared from a
second brood on unnatural food, "that in proportion
as the individual moth is finer, so is the
time required for its metamorphosis longer;
and for this reason the female, which is the larger
and heavier insect, from having to carry her
numerous eggs, will be preceded by the male,
which is smaller and has less to mature." (14.
'Transact. Ent. Soc.' 3rd series, vol. v. p. 486.)
Now as most insects are short-lived, and as
they are exposed to many dangers, it would
manifestly be advantageous to the female to be
impregnated as soon as possible. This end
would be gained by the males being first matured
in large numbers ready for the advent of
the females; and this again would naturally
follow, as Mr. A.R. Wallace has remarked (15.
'Journal of Proc. Ent. Soc.' Feb. 4, 1867, p. lxxi.),
through natural selection; for the smaller males
would be first matured, and thus would pro-