176 THE MALAYAN PAPILIONIDE AS 
‘of Danaide are in the same position: they are slow 
and weak fliers; yet they abound in species and indi- 
viduals, and are the objects of mimicry. The Satyride 
have also probably a means of protection—perhaps their 
keeping always near the ground and their generally 
obscure colours; while the Lycnide and Hesperide 
may find security in their small size and rapid motions. 
In the extensive family of the Nymphalidx, however, 
we find that several of the larger species, of com- 
paratively feeble structure, have their wings modified 
(Cethosia, Limenitis, Junonia, Cynthia), while the large- 
bodied powerful species, which have all an excessively 
rapid flight, have exactly the same form of wing in 
Celebes as in the other islands. On the whole, there- 
fore, we may say that all the butterflies of rather large 
size, conspicuous colours, and not very swift flight have 
been affected in the manner described, while the smaller 
sized and obscure groups, as well as those which are 
the objects of mimicry, and also those of exceedingly 
swift flight have remained unaffected. 
It would thus appear as if there must be (or once 
have been) in the island of Celebes, some peculiar 
enemy to these larger-sized butterflies which does not 
exist, or is less abundant, in the surrounding islands. 
Increased powers of flight, or rapidity of turning, was 
advantageous in baffling this enemy; and the peculiar 
form of wing necessary to give this would be readily 
acquired by the action of “natural selection” on the 
slight variations of form that are continually occurring. 
Such an enemy one would naturally suppose to be 
