418 



THE COMMON BUTTERFLIES OF THE PLAINS 

 OF INDIA 



By 



L. 0. H. Young, b.a., f.e.s., f.z.s. 



PART II. 



(With Plate B.) 



(Continued from <page 579 of Vol. XVI.) 



Genus Hypolimnas. 



This genus contains two species, both abundantly and universally 

 distributed in our area and both of remarkable interest on account of 

 the peculiar form of sexual dimorphism they display. That is to say, 

 while the males, which resemble each other rather closely, correspond 

 to the usual vanessid form of the allied genera, the females bear no 

 resemblance to them in shape or colour but instead mimic very closely 

 species of two other genera, Euploea core and Limnas (Danais 

 chrysippus, in no way related to them. 



The reason why they mimic these two species is obvious because 

 the latter owing to their nauseous taste are protected from the natural 

 enemies of butterflies — lizards, birds, dragonflies and so forth. It is 

 also easy to understand why Nature, which is another name for Pro- 

 vidence, has ordained that the mimicry should only appear in the female 

 as the latter in fulfilling its ordinary functions has to fly slowly from 

 plant to plant and settle constantly to lay her eggs and is consequently 

 far more exposed to danger than the male. 



As to how the mimicry was originally brought about however and 

 became perpetuated under the ordinary laws of heredity in one sex 

 only is a far more difficult problem of evolution to solve, and would 

 take too long to discuss here. The female of H.bolina, but for the 

 difference in shape might be considered only a melanised form of the 

 male and from the moment that mimicry began in the direction of 

 the present form would acquire a certain protection from a resemblance 

 however superficial to E. core- The case of H. miSSippus however is 

 different, for the male and female are absolutely unlike and it is difficult 

 to understand, if the old adage naiura saltum non facit be granted, 

 why any of the intermediate stages should have survived as more fit 

 than the presumed original type. 



