Mimetic Attraction. 329 



Miillerian, and an addition is thus supplied to the evidence 

 already existing in favour of the distasteful quahties of 

 this and other Pierine genera,* 



Conclusion. If we take a comprehensive survey of the 

 whole butterfly facies of the neotropical region, we cannot 

 fail to be struck with the numerous cases of mimetic assimi- 

 lation which it presents. It would in fact almost seem 

 that scarcely auy conspicuous form is completely isolated. 

 In a region where enemies to insect life are so numerous, 

 and competition for existence is so keen, a butterfly can 

 hardly afford to be conspicuous unless it is also distaste- 

 ful ; nor is the mere individual possession of these 

 qualities in the majority of instances suflicient for safety. 

 Any form that requires to establish a reputation for 

 inedibility, must as it were seek allies ; and no sooner does 

 it make a bid for survival as a nauseous species, than it 

 becomes subject to the influence of mimetic attraction, 

 and probably finds itself drawn into the vortex of one of 

 the great Miillerian associations. 



It is no doubt true that the process of mimetic assimi- 

 lation is subject to limitation by the operation of other 

 forces. Thus it may be needful that the resemblance to 

 a model, though close enough to deceive enemies, shouid 

 not be so close as to interfere with due recognition 

 between the sexes. We know little of the means by 

 which insects recognise each other, but there are at least 

 some grounds for thinking that they are assisted at times 

 by external marks. This may afford one reason for the dif- 

 ferent ways in which the sexes of the same species occasion- 

 ally react to mimetic influences ; and it may possibly be 

 the meaning of the retention of a portion of the original 

 white ground-colour in the males of certain species of 

 Dismorphia. It is also quite conceivable that the aspect 

 of every species is to some extent controlled by its 

 physiological constitution ;t and this fact may tend to 

 disturb the perfect operation of the process of mimetic 

 change. 



But notwithstanding all limitations, it remains the 

 fact that any inedible form, in the midst of competing 



* Vi<Je Trans, Eat. So3. Liiid. 183i, pp. 297, 298 ; ibid., 1896, 

 pp. 74, 76. 



t Vide Presidential Address by Prof, Meldola, Proc. Ent. Soc 

 Lond. 1896, pp. Ixxx. et seqq. 



