190 THE MALAYAN PAPILIONIDJE A3 



richness is partly real and partly apparent. The break- 

 ing up of a district into small isolated portions, as 

 in an archipelago, seems highly favourable to the segre- 

 gation and perpetuation of local peculiarities in certain 

 groups ; so that a species which on a continent might 

 have a wide range, and whose local forms, if any, 

 would be so connected together that it would be im- 

 possible to separate them, may become by isolation 

 reduced to a number of such clearly defined and con- 

 stant forms that we are obliged to count them as 

 species. From this point of view, therefore, the 

 greater proportionate number of Malayan species may 

 be considered as apparent only. Its true superiority 

 is shown, on the other hand, by the possession of 

 three genera and twenty groups of Papilionidas against 

 a single genus and eight groups in South America, 

 and also by the much greater average size of the Ma- 

 layan species. In most other families, however, the 

 reverse is the case, the South American Nymphalida3, 

 Satyridse, and ErycinidaB far surpassing those of the 

 East in number, variety, and beauty. 



The following list, exhibiting the range and distri- 

 bution of each group, will enable us to study more 

 easily their internal and external relations. 



Range of the Groups of Malayan Papilionidce. 

 Ornithoptera. 



1. Prianms - group. Moluccas to Woodlark 



Island 5 species. 



2. Pompeus group. Himalayas to New 



Guinea, (Celebes, maximum) ... ... 11 ,, 



3. Brookeana- group. Sumatra and Borneo... 1 



