124 MIMICRY, AND OTHER PROTECTIVE 



complete. We now enter upon a new phase of the 

 phenomena, and come to creatures whose colours neither 

 conceal them nor make them like vegetable or mineral 

 substances; on the contrary, they are conspicuous 

 enough, but they completely resemble some other 

 creature of a quite different group, while they differ 

 much in outward appearance from those with which 

 all essential parts of their organization show them 

 to be really closely allied. They appear like actors 

 or masqueraders dressed up and painted for amuse- 

 ment, or like swindlers endeavouring to pass them- 

 selves off for well-known and respectable members 

 of society. What is the meaning of this strange 

 travestie ? Does Nature descend to imposture or mas- 

 querade ? We answer, she does not. Her principles 

 are too severe. There is a use in every detail of 

 her handiwork. The resemblance of one animal to 

 another is of exactly the same essential nature as the 

 resemblance to a leaf, or to bark, or to desert sand, 

 and answers exactly the same purpose. In the one 

 case the enemy will not attack the leaf or the bark, 

 and so the disguise is a safeguard ; in the other case 

 it is found that for various reasons the creature re- 

 sembled is passed over, and not attacked by the usual 

 enemies of its order, and thus the creature that 

 resembles it has an equally effectual safeguard. We 

 are plainly shown that the disguise is of the same 

 nature in the two cases, by the occurrence in the 

 same group of one species resembling a vegetable 

 substance, while another resembles a living animal of 



