90 THE CASE OF PAPILIO POLYTES [ch. 



the species Papilio coon which belongs to the same 

 presumably distasteful group as P. aristolochiae. These 

 experiments of Jacobsen's are not so complete as the 

 series on P. polytes, but Professor de Meijere and 

 Mr Fryer have both pointed out that they are capable 

 of being interpreted on the same simple lines. 



Another instance of experimental breeding involving 

 polymorphism and mimicry in the female sex is that 

 of the African Papilio dardanus, but the case is here 

 complicated by the greater number of female forms 

 (cf. pp. 30-33). The data, too, are far more scanty 

 than in the other two cases, but so far as they go 

 there is nothing to preclude an explanation being 

 eventually arrived at on similar lines ^. 



And now we may consider briefly the bearing of 

 these experiments on the theory of mimicry. Through- 

 out the work no individuals intermediate between the 

 three well-marked forms of polytes were met with. 

 There is no difference in appearance between the hetero- 

 zygous and the homozygous mimetic insects, whether 

 they belong to the A or to the H form. The factor 

 X, whether inherited from both parents, or from one 

 only, produces its full effect, and the same is also 

 true of the action of the factor Y. Now the most 

 generally accepted hypothesis as to the formation of 

 these mimetic resemblances supposes that they have 

 been brought about through the gradual operation 

 of natural selection accumulating slight variations. 



1 For further information see Poulton, Trans. Ent. Soc. Lond. 1909, 

 and various notes in Proc. Ent. Soc. Lond. subsequent to tliis date. 



