xxxvl Proceedings of the South African Philosophical Soctety. 
for that purpose, and he needs no other guide. As a proof, the 
young of Cystocelia, which becomes adult only after several moults, 
and in which sexual attraction could not be of any use or value at 
its early stage, is as much splashed and banded with silver in both 
sexes as the adult female, which latter is in several species much 
more brightly decorated than the male. 
The true explanation is that the silvery bands and patches break 
the general outline of the insect at rest, or hidden in the foliage. 
This is also the case for 12 of the 22 South African butter- 
flies alluded to before, in which the under side of the wings 
is brighter than the upper. In 7 of them (Charaxes jahlussa, 
pollux, druceanus pelras, saturnus, castor, brutus) this brightness 1s 
mostly due to a longitudinal central band of silver; when the 
insect is at rest or asleep, this band, by its brilliance, naturally 
throws the lateral parts of the wing in the shade, and the real 
outline of the closed wing disappears. The same result is obtained 
by 5 others, in which, however, the silvery band is replaced by 
silvery patches. J have made experiments in this direction, and if the 
power of sight of birds or insectivorous animals resembles ours, the 
arrangement of the colours will certainly prove baffling. 
We have also in South Africa one case of Dimorphism connected 
with protective colouration in two species of the genus Precis, 
z.c., P. sesamus and P. natalensis. In the colouration of the former, 
which delights in shady places, blue predominates, red being re- 
duced to a mere supra-marginal narrow band, and the under side 
is mottled and protective: in the latter red predominates, blue being 
reduced to a mere marginal dotted band, and the predominant red 
of the under side is certainly not protective. This species, instead 
of shady places, frequents the ‘‘ open, highest point of any neigh- 
bourhood.’’. Now, our colleague, Mr. G. A. K. Marshall, of 
Salisbury, from eggs laid by Precis natalensis has bred Precis 
sesamus: from the red species he has reared the blue one, and 
the red also. Bearing in mind the different habits of what was 
until then considered as two different species, we are compelled 
to conclude that, if one of the progeny develops one colour, that 
colour immediately influences its habitat, as if by intuition of the 
value of its colouring as a protection. 
Not only are the adults in the LepripoprEra protected in number- 
less instances, but the caterpillars are also similarly helped by a 
protective colouration brought about by a resemblance to their 
supports and surroundings. Geometrid larvee everywhere appear 
to resemble twigs in a lesser or greater degree, but I doubt if the 
larva of Boarmia acaciaria, which has now taken here to the oak 
