MIMICRY AND EVOLUTION 145 



hypotheses of both naturalists is proved by many 

 a letter in his published correspondence.^ All 

 this forms a peculiarly fascinating chapter of 

 ancient history, — nevertheless ancient history ; 

 but if we desire to choose a subject because of the 

 light it can throw to-day and is certain to throw 

 to-morrow upon evolution and its causes, there is 

 no study which for promise as weU as performance 

 can be set on a higher level than Mimicry. 



In the course of the following address the word 

 ' Mimicry ' will be used with the restricted mean- 

 ing attached to it by A. E. Wallace. It will 

 be applied solely to the superficial resemblances 

 between animals, and not to their likeness to 

 vegetable or mineral surroundings for the purpose 

 of concealment. 



The study of Mimicry is of the highest value in 

 relation to both evolution itself and the motive 

 causes of evolution. 



Apart from all question of the means by which 

 Mimicry has been produced, it will be generally 

 admitted that the mimetic species has in some 

 way evolved a superficial resemblance to the 

 pattern of one or more species, more or less 

 remote from it in the scale of classification. 

 Looking on the changes by which the resem- 

 blance has been produced as a piece of evolu- 

 tionary history, and, as I have said, disregarding 

 for the moment their causes, we have one of the 



• See pp. 123-9. 

 L 



