268 GENERAL BIOLOGY 



when it occupies its natural surroundings. Exam- 

 ples of this are grouse and woodcock and even 

 domestic poultry. 



Specific Resemblance. The sort of protective 

 resemblance just described is of a general nature; 

 that is, the animal merges into the general back- 

 ground of its surroundings without resembling in 

 particular any one element of its environment. 

 Sometimes, however, the protective resemblance 



FIG. 94. The Katydid (Microcentrum) . The wings are colored and 

 veined like the leaves of the vegetation in the midst of which the insect 

 hides. (After Riley, from Kellogg.) 



takes a more specific form, and an animal is found 

 to resemble some specific object in its environment 

 rather than the general background. Thus, the 

 katydid's wings are veined in such a way as to resem- 

 ble very closely a green leaf, and a common moth- 

 larva not only mimics a dry twig in color and 

 shape, but has the habit of extending its body 

 out into the air from a branch so as to make the 

 imitation almost perfect. Such examples may 

 be found almost anywhere in the woods and fields, 

 but they appear to be especially plentiful in the 

 tropics. 



