XI] CONCLUSION 149 



As many of the factors are common to various groups 

 of butterflies it is to be expected that certain of the 

 colour patterns exhibited by one group should be 

 paralleled by certain of those found in another group. 

 That cases of resemblance should tend to run in parallel 

 series in different groups is also to be expected, for 

 in some groups the number of factors in common is 

 likely to be greater than in other groups. In con- 

 sonance with this view is the fact that where poly- 

 morphism occurs among the females of a mimicking 

 species the models, though often widely different in 

 appearance, are, as a rule, closely related. Some of 

 the Asiatic Papilios, for instance, resemble Danaines, 

 while others resemble Pharmacophagus Papilios. But 

 although the polymorphism exhibited by the females of 

 a given species may be very marked, we do not find 

 one of them resembling a Danaine and another a 

 Pharmacophagus Swallow-tail. The models of a poly- 

 morphic mimic are almost always closely related 

 species^. 



In discussing the problems of mimicry more atten- 

 tion is naturally paid to groups which exhibit the 

 phenomenon than to those which either do not do so, 

 or else only do so to a very limited extent. Yet the 

 latter may be of considerable interest. Among the 

 Pieridae of the Old World the phenomenon of mimicry 

 is very rare. Pareronia and Aporia agathon conform 



1 As examples may be mentioned P. polytes, HypoUmnas rmsippus, 

 H. dubius, and Paeudaoraea hobleyi. With the exception of the planemoidea 

 form it is true also for P. dardanus, the most polymorphic of them all. 



