45 
1878.] Colouration of the Organic World . 
garb of whites, blacks, and greys. It can, further, scarcely 
be contended that the land-shells of any country are more 
vividly and intense coloured than the marine shells of its 
coasts, many of which are as highly decorated within as 
without ; yet a land-shell will doubtless receive a larger 
share of the solar radiations than a sea-shell. 
Again, whilst there is thus abundant proof that an aquatic 
or even a deep-sea existence is not necessarily incompatible 
with a rich colouration, we find certain groups — the aquatic 
insedts — ordinarily plain in their hues. The water-beetles, 
chiefly frequenting shallow pools and rivers, present ordi- 
narily a dark olive, black, or brown colouration, relieved at 
most with rusty yellow, and those of tropical climates show 
little, if any, pre-eminence in this respedt over their allies 
from colder regions. But these beetles, be it noted, if devoid 
of splendour, are not etiolated. The water-scorpion, water- 
boatman, and other aquatic Hemiptera, though living rather 
on than in the water, and fully exposed to light, are also 
remarkably plain in their colouration. 
We have repeatedly referred to nodturnal animals ; but it 
will be observed that in the higher forms of life the common 
views concerning their dominant colours scarcely hold good. 
Thus the owls, though not decked out with any metallic 
hues, differ little in the general charadter of their colouration 
from their diurnal kindred, the hawks, presenting bold, well- 
defined patterns, and a variety of black, fawn, brown, buff, 
and white shades. Few mammals display more vivid hues 
than the Felidae, most of which are unquestionably noc- 
turnal. Many nightly or subterranean insedts, also, such 
as Sphodms lencopthalmus and Pristonychus terricola, show no 
signs of etiolation. Even the common cockroach makes no 
approach to that pallid, ghastly hue which is commonly 
supposed charadteristic of animals inhabiting sunless local- 
ities. Amongst nodturnal species we believe few, if any, 
instances can be found where the male surpasses the female 
in brightness or depth of colouring. 
Mr. Wallace, however, whilst going perhaps even farther 
than we should be prepared to accompany him in the re- 
jedtion of the theory which regards animal colouration as 
diredtly proportionate to the intensity of solar radiation, 
gives some curious instances of phenomena proving that in 
certain cases light has a diredt adtion upon the colours of 
organic beings. Thus Mr. T. W. Wood, some time ago, 
pointed out that the chrysalids of the small “ cabbage 
white ” ( Pontia raped) varied in colour when the larvae had 
been fed up in boxes lined with different coloured materials. 
