here they differ;
the female being black, and the male brown in Anthophora retusa, while
in Andraena fulva the female is more brightly coloured than the male. Of
the great order of beetles (Coleoptera) the same thing may be said.
Though often so rich and varied in their colours the sexes are usually
alike, and Mr. Darwin was only able to find about a dozen cases in which
there was any conspicuous difference between them.[119] They exhibit,
however, numerous sexual characters, in the length of the antennae, and
in horns, legs, or jaws remarkably enlarged or curiously modified in the
male sex.

It is in the family of dragonflies (order Neuroptera) that we first meet
with numerous cases of distinctive sexual coloration. In some of the
Agrionidae the males have the bodies rich blue and the wings black,
while the females have the bodies green and the wings transparent. In
the North American genus Hetaerina the males alone have a carmine spot
at the base of each wing; but in some other genera the sexes hardly
differ at all.

The great order of Lepidoptera, including the butterflies and moths,
affords us the most numerous and striking examples of diversity of
sexual colouring. Among the moths the difference is usually but slight,
being manifested in a greater intensity of the colour of the smaller
winged male; but in a few cases there is a decided difference, as in the
ghost-moth (Hepialus humuli), in which the male is pure white, while the
female is yellow with darker markings. This may be a recognition colour,
enabling the female more readily to discover her mate; and this view
receives some support from the fact that in the Shetland Islands the
male is almost as yellow as the female, since it has been suggested that
at midsummer, when this moth appears, there is in that high latitude
sufficient twilight all night to render any special coloration
unnecessary.[120]

Butterflies present us with a wonderful amount of sexual difference of
colour, in many cases so remarkable that the two sexes of the same
species remained for many years under different names and were thought
to be quite distinct species. We find, however, every gradation from
perfect identity to complete diversity, and in some cases we are able to
see a reason for this difference. Beginning with the most extraordinary
cases of diversity--as in Diadema misippus, where the male is black,
ornamented with a large white spot on each wing margined with rich
changea