different forms of the same species live side by side and 

 among them are to be found those, the resemblance of 

 which to leaves is extremely slight. All these facts, and es- 

 pecially the frequently recurring retrogression of the leaf- 

 like appearance, justify serious doubt regarding the Dar- 

 winian assumption, that adaptation was a necessity for the 

 forest-butterilies on account of the protection which it pro- 

 vided. 



An eye witness furthermore declares that the butter- 

 flies that resemble leaves most closely do not always alight 

 on withered leaves, on which they would be almost invis- 

 ible, but frequently rest on a green background, against 

 which they show ofif very clearly, and therefore could not 

 long escape the keen eye of birds. Besides, these butter- 

 flies are but seldom pursued by the birds, of which there 

 is question here, and hence are in no need of protection. 



The longer Eimer devoted his attention to the origin of 

 this resemblance the more "the poetic picture of the imi- 

 tated leaf" vanished out of sight, and he became convinced 

 that it involved the necessary expression of the lines of 

 development, which the respective beings were bound to 

 follow, and that there was no question of imitation. 



Apart from'the resemblance to leaves, by reason of 

 regular changes of color, design, and wing-structure, nu- 

 merous non-related butterflies often develop such wonder- 

 ful similarities — which are not, as hitherto supposed, imi- 

 tations or disguises produced by selection, but are either 

 the outcome o'f an entirely independent uniformity of devel- 

 opment or, at least, of its consequence — that it must be 



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