362 THE ZOOLOGIST. 



by many enthusiastic students in bionomics. Solitary instances, 

 or that of a single species without reference to its congeneric 

 allies, afford but a doubtful testimony to mimetic resemblances. 

 This was clearly seen and enunciated by Darwin himself: — " If 

 Green Woodpeckers alone had existed, and we did not know that 

 there were many black and pied kinds, I dare say that we should 

 have thought that the green colour was a beautiful adaptation to 

 conceal this tree-frequenting bird from its enemies ; and con- 

 sequently that it was a character of importance, and had been 

 acquired through natural selection ; as it is, the colour is probably 

 in chief part due to sexual selection."* In fact, much evolutionary 

 controversy is simply intellectual fencing, and what Schopenhauer 

 has defined as " controversial Dialectic, Dialectica eri&tica." 

 Mimicry, again, is often much obscured by plates in illustrated 

 books which are intended to support the theory. As an example, 

 in the excellent 'Royal Natural History' f appears a coloured 

 plate, entitled " Mimicry in Insects." Here a number of various 

 insects of different orders and diverse habits are brought together 

 in the midst of inappropriate — or inartistic — foliage, with the 

 result that there is no apparent or sufficient mimicry to deceive 

 the most careless enemy, or the most inexperienced entomologist. 

 In fact, as a support to the theory, one can only conclude that 

 either nature, or the artist, is at fault. Again, a comparative 

 immunity from attack is often ultimately proved to be alone the 

 case. A recent writer has observed : — " It is well known, and I 

 have myself observed, that all our ' Cabbage ' Butterflies are 

 immune from attacks of birds, J presumably because of some 

 unpleasant taste or smell. Wasps, however, have twice been 

 observed by me in the act of devouring these butterflies. Ear- 

 wigs, too, which undoubtedly possess an unpleasant smell when 

 irritated, fall victims to Wasps, in spite of their malodorous 

 attributes." § 



To conclude a discursus, which in itself appears some- 

 what controversial, it may be better to give some instances of 



* ' Origin of Species,' 6th edit. p. 158. 

 | Vol. vi. 



J This is a direct contradiction to the testimony of Mr. Furneaux 

 (cf. ante, p. 328). 



§ O. H. Latter, ' Natural Science,' vol. vi. p. 151. 



