THE STRUGGLE Foil EXISTENCE 



of the wings are dark, with purple ami orange markings, 

 so that wiien flying, the butterfly is quite conspicuous. 



Then, again, there are the small green snakes that live 

 in the grass; the eai'th-colored snakes that live along the 

 bare roadsides or in 

 bare fields; the tree 

 iVogs that have grown 

 to imitate the bark 

 of the trees on which 

 they live or, if they 

 live among the leaves, 

 then have grown to 

 resemble the leaves 

 in color. 



A very interesting 

 and I'emarkable case 

 of protective resem- 

 blance is seen among 

 tliose animals in which 

 there is an actual 

 change of color of their fur coats to correspond to the 

 season. The American hare (called the white rabbit) in 

 summer is of a cinnamon brown; but, as winter comes 

 on, its coat turns to a white color. 



Again, certain spiders that live in flowers are colored like 

 the flowers, so that they remain hidden and lie in wait to 

 catch their prey of unsuspecting insects that visit such 

 flowers for nectar. Such resemblances are known as ag- 

 gressi ve resemb lances . 



Mimicry. — In the struggle for existence, the weaker or 

 more vulnerable animal often happens to vary in such a 

 manner that it resembles a stronger or more aggressive 



Kallinia. 



