354 



ELEMENTARY BIOLOGY 



brightening of the color of canaries by a regulation of the diet, 

 and by a change in the color of many insects with the change 



of diet. On the other hand, if a color 

 is to protect, it can do so only in rela- 

 tion to an eye that fails to discriminate. 

 But if the enemy finds his prey by 

 means of smell or some other sense, 

 the color cannot be a protection. 



People have frequently made the mis- 

 take, also, of supposing that other animals 

 see exactly as we do. What looks alike 

 to us may be readily distinguished by 

 other animals ; and the opposite is also 

 true. Thus, the white spots at the rear 

 end of a deer, or the white stripes on 

 a badger, make these animals conspicu- 

 ous in our sight ; but from the point of 

 view to be obtained by eyes that are 

 close to the ground these white spots merge with the light of the 

 sky, and the outlines of the animal are as completely lost as are 

 those of the zebra or the tiger among the stems of the underbrush.^ 



Fig. 170. Walking-leaf insect 



This insect, related to tlie locust 

 and the katydid, resembles the 

 foliage upon which it crawls. ( X 3) 



Fig. 171. Tree hoppers (Memluvcis biuotata) 



These small insects resemble miniature quail quite as closely as other animals "mimic " 

 their models. Yet there is no conceivable advantage to the insect in this resemblance 



402. Protective resemblances. In some animals the mottlings 

 and striping are often very close imitations of particular kinds 

 of backgrounds, and this resemblance is further heightened in 

 many animals by peculiar forms (see Figs. i68, 170). 



1 The art of " camouflage " as developed during the Great War rested 

 largely on the observations of naturalists on protective coloration. 



