THK< >RETICAL BIOLOGY 



465 



similar to Kallima. Animals living on the snow as in the Arctic 

 regions are often white; the polar bear and arctic fox are 

 familiar examples; some change their colors, being dark in 

 summer and white in winter. Desert animals are often yellowish ; 

 many fishes are the same color as the bottom upon which tl 

 lie or the plants and animals amongst which they swim. 



When one animal which is practically defenseless resembles 

 another which has some marked means of protecting itself, the 

 phenomenon is known as mimicry; this term is not intended 

 to imply that there is any 

 conscious imitation on the 

 part of the more helpless 

 animal. The insects, again, 

 supply some of the best 

 examples of mimicry. The 

 humming-bird moth, Maro- 

 glossa titan, so closely re- 

 sembles a humming bird in 

 shape and color that it has 

 frequently been shot by 

 hunters, but its resemblance 

 to the bird serves to pro- 

 tect it from various insec- 

 tivorous birds to which it 

 might otherwise fall a prey. 

 In the same way a harm- 

 less beetle, Coloborhombus 

 fasciatipennis, of Borneo, 

 is protected by its close 

 resemblance to a large 

 black wasp, Mygnimia avi- 



culus (Fig. 424). Some species of butterflies are much disliked 

 by birds because they are bad-tasting and so they are unmolested ; 

 certain other butterflies which are perfectly palatable to birds are 

 protected by their striking resemblance to these objectionable 

 species. The common reddish brown monarch butterfly, Anosia 

 plexippus, of North America, is one of these distasteful species; 

 the viceroy butterfly, Basilarchia archippus, closely resembles it 

 in color and markings, but is not distasteful to birds. Another 

 2 u ' 



Fig. 423. Phyllium siccifolium, the leaf insect. 

 (From Brehm's Thierleben.) 



