ix WAENING COLORATION AXD MIMICRY 245 



not been able to keep pace with the variations of the much 

 more numerous imitated form ; another reason may be the 

 ever -increasing acuteness of the enemies, which have again 

 and again detected the imposture and exterminated the 

 feeble race before it has had time to become further modified. 

 The result of this growing acuteness of enemies has been, 

 that those mimics that now survive exhibit, as Mr. Bates well 

 remarks, "a palpably intentional likeness that is perfectly 

 staggering," and also " that those features of the portrait are 

 most attended to by nature which produce the most effective 

 deception when the insects are seen in nature." No one, in 

 fact, can understand the perfection of the imitation who has 

 not seen these species in their native wilds. So complete 

 is it in general effect that in almost every box of butterflies, 

 brought from tropical America by amateurs, are to be found 

 some species of the mimicking Pierida?, Erycinida?, or moths, 

 and the mimicked Heliconida?, placed together under the 

 impression that they are the same species. Yet more ex- 

 traordinary, it sometimes deceives the very insects themselves. 

 Mr. Trimen 'states that the male Danais chrysippus is some- 

 times deceived by the female Diadema bolina which mimics 

 that species. Dr. Fritz Miiller, writing from Brazil to Professor 

 Meldola, says, ,; One of the most interesting of our mimick- 

 ing butterflies is Leptalis melite. The female alone of this 

 species imitates one of our common white Pierida?, which she 

 copies so well that even her own male is often deceived ; for 

 I have repeatedly seen the male pursuing the mimicked 

 species, till, after closely approaching and becoming aware of 

 his error, he suddenly returned." 1 This is evidently not a 

 case of true mimicry, since the species imitated is not pro- 

 tected ; but it may be that the less abundant Leptalis is able 

 to mingle with the female Pierida? and thus obtain partial 

 immunity from attack. Mr. Kirby of the insect department 

 of the British Museum informs me that there are several 

 species of South American Pieridae which the female Leptalis 

 melite very nearly resembles. The case, however, is interest- 

 ing as showing that the butterflies are themselves deceived by 

 a resemblance which is not so great as that of some mimicking 

 species. 



1 R. Meldola in Ann. and Mag. ofNaL Hist., Feb. 1878, p. 158. 



