176 1HE MALAYAN PAPILIONIDJE AS 



of DanaidaB 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 Satyrida) 

 have also probably a means of protection perhaps their 

 keeping always near the ground and their generally 

 obscure colours ; while the Lyca3nida3 and Hesperidse 

 may find security in their small size and rapid motions. 

 In the extensive family of the Nymphalida3, 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 



