VIII THE COLOURS OF INSECTS IN GENERAL 165 
apparent reason why insects should not themselves 
produce lipochromes, and why such lipochromes 
should not occur in the cuticle as in the Crustacea. 
We have seen that lipochromes occur in the elytra 
of Lina populi ; according to Krukenberg they perhaps 
also colour the red lady-birds (Coccionellae) and some 
other red beetles, but whether these are intrinsic or 
derived pigments remains undecided. 
Colours of the Different Orders of 
Insects 
It is interesting to observe the types of colouring 
prevalent in the more important orders of insects. 
Thus in the Orthoptera optical colours seem to be 
practically absent, and deep black is also rare; shades 
of brown, green, and red are perhaps the commonest 
colours, as notice the brown “ stick ” insects, the 
brown and green (or sometimes red) grasshoppers 
and locusts, and so on. Associated with these 
peculiarities of colouring we notice the fact that the 
cuticle is in most cases but slightly developed. The 
relatively sober tints do not, however, prevent the 
Orthoptera often displaying great beauty of colour¬ 
ing. Thus Dr. D. Sharp describes the female of 
Pneumora scutellaris as being “ one of the most 
remarkably coloured of insects.” “ She is of a gay 
green, with pearly - white marks, each of which is 
surrounded by an edging of magenta; . . . the face 
has magenta patches and a large number of tiny 
pearly-white tubercles, each of which when placed 
on a green part is surrounded by a little ring of 
mauve colour.” The male is much plainer, being 
