The Descent of Man

It should also be remembered that many species
of Lepidoptera are liable to considerable
and abrupt variations in colour. A few instances
have been given in this chapter; and many
more may be found in the papers of Mr. Bates
and Mr. Wallace.
With several species the sexes are alike, and
imitate the two sexes of another species. But
Mr. Trimen gives, in the paper already referred
to, three cases in which the sexes of the imitated
form differ from each other in colour, and
the sexes of the imitating form differ in a like
manner. Several cases have also been recorded
where the females alone imitate brilliantlycoloured
and protected species, the males retaining
"the normal aspect of their immediate
congeners." It is here obvious that the successive
variations by which the female has been
modified have been transmitted to her alone. It
is, however, probable that some of the many
successive variations would have been trans-