Mimicry 



"And Hannah, my wife, says she 's heerd o' sech things; 

 She guesses his brain warn't so meller. 

 There 's a thing they call Nat'ral Histerry, she says, 



And, whatever the folks there may tell her, 

 Till it 's settled she 's wrong she Ml jest hold that-air man 

 Was a Nat'ral Histerrical feller." 



Annie Trumbull Slosson. 



MIMICRY 



Protective mimicry as it occurs in animals may be the simula- 

 tion in form or color, or both, of natural objects, or it may be the 

 simulation of the form and color of another animal, which for 

 some reason enjoys immunity from the attacks of species which 

 ordinarily prey upon its kind. Of course this mimicry is uncon- 

 scious and is the result of a slow process of development which 

 has, no doubt, gone on for ages. 



Remarkable instances of mimicry, in which things are simu- 

 lated, are found in the insect world. The ''walking-sticks," as 

 they are called, creatures which resemble the twigs of trees; 

 the "leaf-insects," in which the foliage of plants is apparently 

 reproduced in animate forms; the "leaf-butterfly" of India, in 

 which the form and the color and even the venation of leaves are 

 reproduced, are illustrations of mimicry which are familiar to all 

 who have given any attention to the subject. 



Repulsive objects are frequently mimicked. A spider has 

 been lately described from the Indo-Malayan region, which, as it 

 rests upon the leaves, exactly resembles a patch of bird-lime. 

 The resemblance is so exact as to deceive the most sagacious, 

 and the discovery of the creature was due to the fact that the 

 naturalist who happened to see it observed, to his surprise, that 

 what he was positive was a mass of ordure was actually in 

 motion. A similar case of mimicry is observable among some of 

 the small acontiid moths of North America. One of these is pure 

 white, with the tips of the fore wings dark greenish-brown. It 

 sits on the upper side of leaves, with its fore wings folded over, 

 or rolled about the hind wings, and in this attitude it so nearly 

 approximates in appearance the ordure of a sparrow as to have 

 often deceived me when collecting. 



235 



