The Descent of Man

lue butterflies of the genus Lycaena, illustrate
the various differences in colour between the
sexes, almost as well, though not in so striking
a manner, as the above exotic genera. In Lycaena
agestis both sexes have wings of a brown
colour, bordered with small ocellated orange
spots, and are thus alike. In L. oegon the wings
of the males are of a fine blue, bordered with
black, whilst those of the female are brown,
with a similar border, closely resembling the
wings of L. agestis. Lastly, in L. arion both
sexes are of a blue colour and are very like,
though in the female the edges of the wings are
rather duskier, with the black spots plainer;
and in a bright blue Indian species both sexes
are still more alike.
I have given the foregoing details in order to
shew, in the first place, that when the sexes of
butterflies differ, the male as a general rule is
the more beautiful, and departs more from the
usual type of colouring of the group to which