384 TROPICAL NATURE 



yet, as none of these groups are known to be specially pro- 

 tected, this can hardly be true mimicry. A few species of 

 two other genera in the same country (Eunica and Siderone) 

 also reproduce the same colours, but with only a general 

 resemblance in the markings. Yet again, in tropical America 

 we have species of Apatura which, sometimes in both sexes, 

 sometimes in the female only, exactly imitate the peculiar 

 markings of another genus (Heterochroa) confined to America ; 

 here, again, neither genus is protected, and the similarity 

 must be due to unknown local causes. 



But it is among islands that we find some of the most 

 striking examples of the influence of locality on colour, 

 generally in the direction of paler, but sometimes of darker 

 and more brilliant hues, and often accompanied by an unusual 

 increase of size. Thus in the Moluccas and New Guinea we 

 have several Papilios (P. euchenor, P. ormenus, and P. tydeus) 

 distinguished from their allies by a much paler colour, espe- 

 cially in the females, which are almost white. Many species 

 of Danais (forming the subgenus Ideopsis) are also very pale. 

 But the most curious are the Euploeas, which in the larger 

 islands are usually of rich dark colours, while in the small 

 islands of Banda, Ke, and Matabello at least three species not 

 nearly related to each other (E. hoppf eri, E. euripon, and E. 

 assimilata) are all broadly banded or suffused with white, 

 their allies in the larger islands being in each case very much 

 darker. Again, in the genus Diadema, belonging to a dis- 

 tinct family, three species from the small Aru and Ke islands 

 (D. deois, D. hewitsonii, and D. polymena) are all more 

 conspicuously white-marked than their representatives in the. 

 larger islands. In the beautiful genus Cethosia, a species 

 from the small island of Waigiou (C. cyrene) is the whitest of 

 the genus. Prothoe is represented by a blue species in the 

 continental island of Java, while those inhabiting the ancient 

 insular groups of the Moluccas and New Guinea are all pale 

 yellow or white. The genus Drusilla, almost confined to these 

 islands, comprises many species which are all very pale ; 

 while in the small island of Waigiou is found a very distinct 

 genus, Hyantis, which, though differing completely in the 

 neuration of the wings, has exactly the same pale colours and 

 large ocellated spots as Drusilla. 



