126 The Naturalist in La Plata. 



spiders, wasps, and other dangerous kinds, that 

 it is manifestly a " warning colour," the most 

 universal and best known in nature ; and the 

 grasshopper, I believe, furthermore mimics the 

 fearless demeanour of the protected or venomous 

 species, which birds and other insect-eaters know 

 and respect. It might be supposed that the young 

 Zoniopoda is itself unpalatable ; but this is scarcely 

 probable, for when the deceptive black mask is 

 once dropped, the excessive shyness, love of con- 

 cealment, and protective colouring of the insect 

 show that it is much sought after by birds. 



While setting this down as an undoubted case of 

 " mimicry," although it differs in some respects 

 from all other cases I have seen reported, I cannot 

 help remarking that this most useful word appears 

 to be in some danger of losing the meaning origi- 

 nally attached to it in zoology. There are now 

 very few cases of an accidental resemblance found 

 between two species in nature which are not set 

 down by someone to "mimicry," some in which 

 even the wildest imagination might well fail to see 

 any possible benefit to the supposed mimic. In 

 cases where the outward resemblance of some 

 feeble animal to a widely different and well-pro- 

 tected species, or to some object like a leaf or 

 stick, and where such resemblance is manifestly 

 advantageous and has reacted on and modified the 

 life habits, it is conceivable that slight spontaneous 

 variations in the structure and colouring of the 

 unprotected species have been taken advantage of 

 by the principle of natural selection, and a case of 

 " mimicry " set up, to become more and more 



