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-coloui^d 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 



