SURVIVAL OF THE ADVANTAGEOUS 247 



advantageous it is attained, especially by the sex that 

 needs it most. The female sex becomes conservative or 

 progressive according to the needs of the species, and 

 Natural Selection is limited by no bounds of constitutional 

 difference between the sexes as regards the preservation 

 of the old or the initiation of the new. 



I o. The Space and Time Relatio7iships of the Resemblance 



in Qitestion, 



A mimetic group is found in the same locality, or at 

 least the mimic (Batesian) is not found beyond the range 

 of its model. The types of Common Warning Colours 

 are remarkably local, although probably certain members 

 of the group (being ex hypothesi all specially protected) 

 may sometimes have a wider range than others. When 

 such a mimic as Hypolimnas misipptts can invade and 

 thrive in South America and the Antilles in the absence 

 of its model (Ltmnas chrysippns\ we probably have to do 

 with a Mtillerian rather than a Batesian association.^ 



Looking at the examples broadly, the phenomena are 

 characteristically local. This, although harmonizing with 

 the other suggested explanations, is quite unintelligible 

 if the theory of Internal Causes be adopted. Why should 

 these results if attained independently in the evolution of 

 various forms be attained in the same locality ? The 

 number of patterns and the number of forms is so vast 

 that we must expect a certain amount of accidental 

 resemblance due to internal causes, as has been suggested 

 by Beddard,^ but such resemblances will differ from those 

 under discussion in this among other things — that they 

 will not be characteristically local. The theory of Internal 

 Causes offers us a valid interpretation of such cases, which 

 are, as a rule, readily distinguishable in other ways from 

 those which are here considered. 



There is another aspect of locality which only receives 



^ See also a paper by the present writer on Mimicry in Butterflies of 

 the Ge7ius Hypolimnas in Proc. Amer. Assoc, for Adv. of Sci., Detroit 

 Meeting, 1897, vol. xlvi, p. 242, where other arguments in support of this 

 conclusion are urged. 



2 Animal Coloration, London, 1892, p. 252. 



