xxvl_ Proceedings of the South African Philosophical Society. 
ANNUAL ADDRESS TO THE MEMBERS 
OF THE 
SOUTH AFRICAN PHILOSOPHICAL SOCIETY, 
On OctToBER 3, 1900. 
By THE PREsIDENT, L. Périncugy, F.E.S. 
SoME PuHaseEs oF Insect Lire In SoutH AFRICA. 
I.—Protective Colouration. 
The colouration of invertebrate animals is in many instances due: 
to the presence of certain organic pigments which absorb particular 
light vibrations, and transmit or reflect others in greater or lesser 
degree. 
The utility of colouration and markings in animals and especially 
in insects is very great, and in the present address I shall deal with 
protective colouration, which is of two main sorts, viz. :— 
I. Assimilation to the tint of the inanimate surroundings securing— 
(a) Resemblance as an aid to aggression in addition to simple: 
protective resemblance, 
(b) Protective resemblance pure and simple. 
II. Display of brilliant colours : 
| (a) Indicating that the species is unpalatable, or 
(b) Imitation by a perfectly palatable species of one that had 
better not be touched. 
But no one of these protective resemblances is absolutely restricted 
to a single use, nor is it attained by a single means. For instance, in 
the case of the Mantidous insect Phyllocrania insignis, the colouration 
is brown with lighter or darker tints imitating those of a withering 
or withered leaf, while at the same time this protective resemblance 
is increased by the development of foliated appendages reproducing 
the very shape of the leaf. In all cases of aggressive and protective 
resemblance occurring in South Africa it will be found that colour 
and modification of shape go together, and that in cases of simple 
protective resemblance a modification of shape, or gait, or flight 
completes the deception. 
I shall deal first with protective colouration as an aid to aggression 
as well as a protection from enemies, and this for shortness I shall 
