Evidences of Theory of Natural Selection. 327 
in order that the imitating species may be mistaken 
for the imitated, and thus participate in some ad- 
vantage which the latter enjoys. For instance, if, as 
in the case of the conspicuously-coloured caterpillars, 
it is of advantage to an ill-savoured species that it 
should hold out a warning to enemies, clearly it may 
be of no less advantage to a well-savoured species 
that it should borrow this flag, and thus be mistaken 
for its ill-savoured neighbour. Now, the extent to 
which this device of mimicry is carried is highly re- 
markable, not only in respect of the number of its 
cases, but also in respect of the astonishing accuracy 
which in most of these cases is exhibited by the 
imitation. There need be little or virtually no 
zoological affinity between the imitating and the 
imitated forms; that is to say, in some cases the 
zoological affinity is not closer than ordinal, and 
therefore cannot possibly be ascribed to kinship. 
Like all the other branches of the general subject of 
protective resemblance in form or colouring, this 
branch has already been so largely illustrated by 
previous writers, that, as in the previous cases, I need 
only give one or two examples. Those which I 
choose are chosen on account of the colours concerned 
not being highly varied or brilliant, and therefore 
lending themselves to less ineffectual treatment by 
wood-engraving than is the case where attempts are 
made to render by this means even more remarkable 
instances. (Figs. 113, 114, 115.) 
It is surely apparent, without further comment, that 
it is impossible to imagine stronger evidence in favour 
of natural selection as a true cause in nature, than is 
furnished by this culminating fact in the matter of 
