13 1 THE MALAYAN PAPILIONIVM AS 



group exhibiting it a claim to a higli grade of organ- 

 ization ; still less can this be allowed when another 

 group along with perfection of structure in the same 

 organs, exhibits modifications peculiar to it, together 

 with the possession of an organ which in the re- 

 mainder of the order is altogether wanting. This is, 

 however, the position of the Papilionidae. The per- 

 fect insects possess two characters quite peculiar to 

 them. Mr. Edward Doubleday, in his " Genera of 

 Diurnal Lepidoptera," says, " The Papilionidae may 

 be known by the apparently four-branched median 

 nervule and the spur on the anterior tibiae, charac- 

 ters found in no other family." The four -branched 

 median nervule is a character so constant, so pecu- 

 liar, and so well marked, as to enable a person to 

 tell, at a glance at the wings only of a butterfly, 

 whether it does or does not belong to this family ; 

 and I am not aware that any other group of butter- 

 flies, at all comparable to this in extent and modifi- 

 cations of form, possesses a character in its neuration 

 to which the same degree of certainty can be attached. 

 The spur on the anterior tibiae is also found in some 

 of the Hesperidae, and is therefore supposed to show a 

 direct affinity between the two groups : but I do not 

 imagine it can counterbalance the differences in neura- 

 tion and in every other part of their organization. 

 The most characteristic feature of the Papilionidae, 

 however, and that on which I think insufficient 

 stress has been laid, is undoubtedly the peculiar 

 structure of the larvae. These all possess an extra- 



