270 
DARWINISM 
CHAl*. 
is smaller and much less protectively formed and coloured. 
In the bees and wasps (Hymenoptera) it is also the rule that 
the sexes are alike in colour, though there are several cases 
among solitary bees where they differ; the female being 
black, and the male brown in Anthophora retusa, while in 
Anclrsena 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 con¬ 
spicuous difference between them. 1 They exhibit, however, 
numerous sexual characters, in the length of the antennre, and 
in horns, legs, or jaws remarkably enlarged or curiously modi¬ 
fied 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 Agrionidse 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 Hetserina 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 differ¬ 
ence is usually but slight, being manifested in a greater inten¬ 
sity 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 unneces¬ 
sary. 2 
Butterflies present us with a wonderful amount of sexual 
1 Darwin’s Descent of Man , p. 294, and footnote. 
- Nature, 1871, p. 489. 
