1 878.] 
Colouration of the Organic World. 
43 
This circumstance, like the etiolation of plants reared up in 
darkness, is certainly in favour of the view that light is not 
without influence upon organic colouration ; but, on the 
other hand, let us consider the after-life of some of these 
dull-looking beetle-grubs. The most gorgeous, perhaps, of 
all Coleoptera are the Buprestidae. These creatures spend 
the whole of their larval and pupal life within the trunks of 
trees, and consequently in total darkness. When mature, 
indeed, they sport for a time in the chequered sunlight of 
the woodlands. But why, if light be the main cause of 
animal colouration, should they be so far superior in bril- 
liance to the Longicornes, or wood-beetles, which from birth 
to death are exposed to precisely the same circumstances ? 
Taking the opposite extreme, the Staphylinidae — of which 
the common ‘‘devil’s coach-horse” is a familiar example, 
rank in appearance among the dullest and least decorated 
of all the insedt tribes, whether they inhabit cold or warm 
climates ; yet these creatures, instead of leading the earlier 
part of their life in complete and constant darkness, are 
adtive when larvae, and may be seen running about in the 
daylight, seeking for prey. Surely, therefore, being so much 
more exposed to light than the Buprestidae or the Cetoniadae, 
they ought, on the theory we are examining, to be at least 
correspondingly beautiful. Let us turn to the Melolonthidae, 
of which the common and destructive insedt known as the 
cockchafer may serve as the type. Their early life is spent 
in darkness, since when larvae they live underground, de- 
vouring the roots of plants. When mature their colours 
must be pronounced far less brilliant than those of their 
near allies, the rose-beetles (Cetoniadae), which are equally 
nursed in darkness. It will be of course objected that the 
adult cockchafer is a nocturnal — or at least a twilight- 
loving — insect, while the rose-beetle feeds and flies by day. 
We will therefore take another instance — that of the 
Elateridae, or click-beetles. As larvae they, like the imma- 
ture cockchafer, live underground, but when mature they 
are diurnal in their habits ; yet the general colouration of 
the family is what some people call “ sober,” scarcely more 
gay than that of the Melolonthidae, and forming a most 
striking contrast to that of the Buprestidae, whom they so 
closely approach at once in their structure and in the degree 
of light which they encounter, both in their earlier stages 
and in mature life. Again, we may consider the weevils 
(Curculionidse), all of them when larvae burrowing from 
daylight in the interior of fruits and in the buds and stems 
of plants; yet when mature some of them — c.g. } the 
