114 MIMICRY, AND OTHER PROTECTIVE 
Heliconide and Danaide, protected by a disagree- 
able flavour, have the females as bright and conspi- 
cuous as the males, and very rarely differing at all 
from them. The stinging Hymenoptera have the two 
sexes equally well coloured. The Carabide, the Coc- 
cinellidee, Chrysomelide, and the Telephori have both 
sexes equally conspicuous, and seldom differing in 
colours. The brilliant Curculios, which are protected 
by their hardness, are brilliant in both sexes. Lastly, 
the glittering Cetoniade and Buprestide, which seem 
to be protected by their hard and polished coats, their 
rapid motions, and peculiar habits, present few sexual 
differences of colour, while sexual selection has often 
manifested itself by structural differences, such as 
horns, spines, or other processes. 
Cause of the dull Colours of Female Birds. 
The same law manifests itself in Birds. The female 
while sitting on her eggs requires protection by con- 
cealment to a much greater extent than the male; and 
we accordingly find that in a large majority of the 
eases in which the male birds are distinguished by 
unusual brilliancy of plumage, the females are much 
more obscure, and often remarkably plain-coloured. 
The exceptions are such as eminently to prove the 
rule, for in most cases we can see a very good reason 
for them. In particular, there are a few instances 
among wading and gallinaceous birds in which the 
female has decidedly more. brilliant colours than the 
male; but it is a most curious and interesting fact 
