PEOTECTIVE MIMICRY 217 



Diadema dubia, et le Papilio Westermanni, trois 

 Lepidopteres qui se ressemblent presque completement 

 par le port, le dessin, et la couleur, quoique apparte- 

 nant a des genres fort eloignes et de tribus differentes.' 



From 1836, and the even earlier dates at which 

 these remarkable resemblances had been noticed, 

 until 1862, no attempt at explanation had been made ; 

 but in that year Mr. Bates's classical paper appeared. 1 

 In this admirable~essay the author showed the advan- 

 tage which must necessarily be gained by a palatable 

 form, hard pressed by enemies, if it sheltered itself 

 under the reputation of some conspicuous species 

 well known to be inedible. 



Only three years before, Darwin, writing to 

 Asa Gray, had said : ' I cannot possibly believe that a 

 false theory would explain so many classes of facts as 

 I think it certainly does explain. On these grounds 

 I drop my anchor, and believe that the difficulties will 

 slowly disappear.' 2 One great difficulty which had 

 so long been a puzzle to naturalists was therefore 

 satisfactorily explained by the new theory, within a 

 few years of Darwin's prediction. 



It is most delightful to read of the interest and 

 enthusiasm with which Bates's paper was received by 

 Darwin. ' In my opinion it is one of the most re- 

 markable and admirable papers I ever read in my 



1 Contributions to an Insect Fauna of the Amazons Valley. 

 Linn. Soc. Trans, vol. xxiii. 



2 Life and Letters, vol. ii. p. 217. 



