142 THE MALAYAN PAP1LIONID& AS 



tinguished by very slight characters, but in most 

 cases so constant in large series of specimens, and 

 so easily separable from each other, that I know not 

 on what principle we can refuse to give them the 

 name and rank of species. One of the best and most 

 orthodox definitions is that of Pritchard, the great 

 ethnologist, who says, that " separate origin and dis- 

 tinctness of race, evinced by a constant transmission of 

 some characteristic peculiarity of organization," consti- 

 tutes a species. Now leaving out the question of 

 " origin," which we cannot determine, and taking 

 only the proof of separate origin, " the constant trans- 

 mission of some characteristic peculiarity of organiza- 

 tion" we have a definition which will compel us to 

 neglect altogether the amount of difference between 

 any two forms, and to consider only whether the dif- 

 ferences that present themselves are permanent. The 

 rule, therefore, I have endeavoured to adopt is, that 

 when the difference between two forms inhabiting 

 separate areas seems quite constant, when it can be 

 defined in words, and when it is not confined to a 

 single peculiarity only, I have considered such forms 

 to be species. When, however, the individuals of 

 each locality vary among themselves, so as to cause 

 the distinctions between the two forms to become 

 inconsiderable and indefinite, or where the differences, 

 though constant, are confined to one particular only, 

 such as size, tint, or a single point of difference in 

 marking or in outline, I class one of the forms as a 

 variety of the other. 



