Proceedings of the South African Philosophical Society. xlv 
This possession by certain groups of insects does not seem to 
materially increase the number of Cantharide, Lycide, or 
Cerambycide in the CoLEoPTERA, or Pentatomide in the HEMIPTERA. 
In the Leprporrsra, the protected Acrea horta or A. rahira, even 
Danais chrysippus, are not excessively abundant. The latter is far 
from having attained the great range of distribution of the com- 
paratively non-protected Vanessa cardui.. The orthopterous species 
of Phymatideus, made so conspicuous by their warning colours, are 
never abundant like so many of their congeners. It is not that they 
are not prolific. On the contrary, the abdomen of the gravid female 
is so distended that she can hardly drag it, and I found that the 
ege-pod of Phymateus leprosus contains as many, even more eggs 
than that of the peregrine and of the migratory locusts. These two 
last-named species have certainly not warning colours in the adult 
stage, yet the young of the migratory one, Pachytilus migratorius, 
are so gaily coloured as to have earned for them the local name of 
‘“‘rooi-batjes,”’ or redcoats. Their smell is also repugnant. Yet they 
cannot be said to derive much profit on that account from depre- 
dations by enemies, and there is nothing to warrant the belief, except 
theoretically, that the adults have lost this warning colouring or that 
nauseous smell, because they have developed a power of flight and of 
sociability which has more than counterbalanced the loss of this 
protective colouration, 
Lastly, as to the third proposition of rejection by foes of the 
insects provided with offensive juices, it must be admitted that 
many of the experiments have been made with domestic animals or 
animals kept in captivity, including my own with Acrea rahira 
and Acrea horta. These examples are not always convincing. My 
fowls last year would not touch, when thrown to them, the cater- 
pillars of our common swallow-tail butterfly, Papilio demoleus, 
which were only too plentiful on my citrus-trees. My ducks, how- 
ever, enjoyed them, although these gaily caparisoned caterpillars 
emit a most pungent scent when alarmed. 
As for the loss occasioned to distasteful species by the attack of 
young and inexperienced enemies, the author of this part of the 
theory, Fritz Muller, and those who believe in it, do not seem to 
have taken into consideration the possibility of characters from the 
same source as that derived from the obtention and the retention 
of malodorous qualities, z.e., natural selection, being equally well 
developed in the young of the enemy. Our attention is called to 
a few cases of butterflies with the wings partly eaten as if by a 
lizard or a bird, in order to prove that a young or foolish enemy 
had failed in catching the insect. But who is the observer who 
