ADAPTATION OF ORGANISMS 



321 



The white of the Foxes, Hares, and Owls of alpine and 

 arctic regions; the green color of foliage-dwelling Insects 

 and Frogs; the tendency toward fawn and gray of desert 

 Insects, Reptiles, Birds, and Mam- 

 mals; the olive upper surface of 

 the bodies of brook Fishes; the 

 steel gray above and white below 

 of sea Birds which harmonize with 

 sea and sky when viewed from 

 above and below respectively - 

 the number of such cases is legion. 

 Gazelles living on the lava fields 

 of volcanic regions are dark gray, 

 while those of the great stretches 

 of sand plains are white the 

 same species exhibiting regional 

 variations in color which blend 

 with the surroundings. Further- 

 more, the same individual may 

 vary in color with the seasonal 

 changes in its environment, or 

 present different color schemes 

 in different localities. Thus the 

 summer coat colors of the Arctic Fox and the Weasel har- 

 monize with the browns of rocks; and the winter coat of 

 white with snow-clad nature. And the Chameleons are by 

 no means unique in their ability to change color very rapidly 

 in response to that of their immediate surroundings. 



But confusion is worse confounded when to harmonizing 

 color is added harmonizing form, striking examples of which 

 are the Dead-leaf Butterfly (Kallima) of the East Indian 

 region, the familiar Walking-sticks (Diapheromera), and the 

 caterpillars of Geometrid Moths. (Figs. 171 , 172, 173. J 



FIG. 171. Dead-leaf Butterfly, 

 Kallima paralecta. (After Weis- 

 mann.) 



