The Descent of Man

of a dog, it would be one of the most imposing
animals in the world.
The colouring of insects is a complex and obscure
subject. When the male differs slightly
from the female, and neither are brilliantlycoloured,
it is probable that the sexes have varied
in a slightly different manner, and that the
variations have been transmitted by each sex to
the same without any benefit or evil thus accruing.
When the male is brilliantly-coloured
and differs conspicuously from the female, as
with some dragon-flies and many butterflies, it
is probable that he owes his colours to sexual
selection; whilst the female has retained a primordial
or very ancient type of colouring,
slightly modified by the agencies before explained.
But in some cases the female has apparently
been made obscure by variations transmitted
to her alone, as a means of direct protection;
and it is almost certain that she has sometimes
been made brilliant, so as to imitate other pro-