134 THE MALAYAN PAPILIONIDA AS 
group exhibiting it a claim to a high 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 Papilionide. The per- 
fect insects possess two characters quite peculiar to 
them. Mr. Edward Doubleday, ia his “ Genera of 
Diurnal Lepidoptera,” says, ‘‘The Papilionide may 
be known by the apparently four-branched median 
nervule and the spur on the anterior tibie, 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 Hesperide, 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 Papilionide, 
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- 
