Mimicry Among Animals 



aquarium of the Zoological Society some slender 

 green pipe-fish which fasten themselves to any 

 object at the bottom by their prehensile tails, 

 and float about with the current, looking ex. 

 like some cylindrical algae. 



It is, however, in the insect world that this 

 principle of the adaptation of animals to their 

 environment is most fully an'd strikingly d< 

 oped. In order to understand how general this 

 is, it is necessary to enter somewhat into details, 

 as we shall thereby be better able to appreciate 

 the significance of the still more remarkable 

 phenomena we shall presently have to discuss. 

 It seems to be in proportion to their sluggish 

 motions or the absence of other means of defence, 

 that insects possess the protective colouring. 

 In the tropics there are thousands of species of 

 insects which rest during the day clinging to the 

 bark of dead or fallen trees; and the greater por- 

 tion of these are delicately m< >ttled with gray and 

 brown tints, which though symmetrically dis- 

 posed and infinitely varied, yet blend so com- 

 pletely with the usual colours of the bark that 

 at two or three feet distance they are quite un- 

 distinguishablc. In some cases a species is 

 known to frequent only one spe< ies < >£ I ree. This 

 is the case with the common South American 

 long-horned beetle (Onychocerus scorpio) which, 

 Mr. Bates informed me, is found only on a rough- 

 barked tree, called Tapiriba, on the Amazon. 

 It is very abundant, but so exactly docs it re- 

 semble the bark m colour and rugosity, and so 

 81 



