54 
Action of Light upon Colouration. [January, 
real protection to them.” This rule, however, is by no 
means universal. The fire-wasp ( Chryseis ) and not a few 
other Hymenoptera have brilliantly-coloured bodies, but 
colourless and transparent wings, which when expanded and 
in aCtion are scarcely visible. In numbers of Lepidoptera 
the more intense colours, especially reds, are found entirely 
or mainly on the posterior wings, which extend to a less 
distance from the body than do the anterior pair. In many 
cases again Lepidoptera, Coleoptera, and Hymenoptera 
display conspicuous colours at the extremity of the abdomen, 
where a blow from the beak of a bird would doubtless per- 
manently disable. 
A question may here arise concerning the use of the 
colouration of the posterior or true wings in certain beetles, 
a circumstance not sufficiently examined. Whilst these 
wings in the vast majority of Coleopterous species are 
colourless, or at most of a very faint yellowish hue, in the 
Colorado beetle they are pink, and purple in several Chryso- 
chroas , Pachnodas , and Lomapteras. Why should these species 
thus differ from other closely-allied forms, with whom 
they appear to agree most closely in their habits ? 
We have no doubt that Mr. Wallace’s formal declaration 
against the dodtrine of Sexual Selection will attract the 
attention of disbelievers in Evolution, and we venture to 
hope that all the comments which will be elicited may not 
be beside the question. 
