IV. MIMICRY, WITH EXAMPLES 



Bates' Theory of Mimicry 



BATES, in 1862, was the first to observe in South America 

 certain butterflies that were mimicked by others. These 

 observations were pubhshed in the "Linnean Society 

 Transaction," Volume XXIII. Four years later, Wal- 

 lace described similar cases which he discovered in Asia and 

 in the Malay region. Later, Trimen recognized similar cases 

 in Africa. This subject has been elaborated by Belt, Meldola, 

 Miiller, Poulton, Marshall, and others. 



The conditions under which protective mimicry occur, 

 according to Wallace in "Darwinism," pp. 264, 265, are as 

 follows: "The imitative species occurs in the same area and 

 occupies the same station as the imitated. The imitators 

 are always the more defenceless, are always less numerous 

 in individuals, and they differ from the bulk of their allies. 

 The imitation, however minute, is external and visible only, 

 never (extending to internal characters or to such as do not 

 affect the external appearance." These observations were 

 founded on butterflies occurring in the tropics where examples 

 of mimicry are much more numerous than northward in the 

 temperate region. 



The females are much more liable to protective mimicry 

 than the males. Wallace explains this by asserting that 

 "their slower flight, when laden with eggs, and their exposure 

 to attack while in the act of depositing their eggs under the 

 leaves, render it especially advantageous for them to have 

 additional protection." Weismann remarks ^ that "Whenever 

 we find protected insects enjoying immunity from foes, we also 

 see mimickers, sometimes only single, sometimes several, and 



^"Studies in the Theory of Descent," 1882, p. 649. 

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