ANIMAL SELF-DEFENSE. 599 



or odors, which are not a matter of consciousness or will. In illustra- 

 tion of this method of defense, it will be sufficient to quote the f ollow- 

 ino- : " In South America there is a family of butterflies termed Heli- 

 co?iidce, which are very conspicuously colored and slow in flight, and 

 yet the individuals abound in prodigious numbers, and take no precau- 

 tions to conceal themselves, even when at rest during the night. Mr. 

 Bates found that these conspicuous butterflies had a very strong and 

 disagreeable odor ; so much so, that any one handling them, and 

 squeezing them as a collector must do, has his fingers stained and so 

 infected by the smell as to require time and much trouble to remove 

 it. It is suggested that this unpleasant quality is the cause of the 

 abundance of the Heliconidce ; Mr. Bates and other observers report- 

 ing that they have never seen them attacked by the birds, reptiles, or 

 insects, which prey upon other lepidoptera." 



Great numbers of animals are permanently colored so as to har- 

 monize with their favorite surroundings. This obscure coloring may 

 be either for the purpose of securing prey, or for concealment. The 

 banded colors of the tiger perfectly blend with the lights and shadows 

 in the jungle-grass. Those forest animals which live on the ground, 

 as game-birds, deer, rabbit, or squirrel, are of brown or neutral hues, 

 which assimilate to the color of dead leaves and tree-trunks ; and they 

 are quite impossible to discover as long as they remain motionless. 

 Animals of the desert are dull or rust colored, or of some light tint. 

 Insects, frogs, and lizards, which live among the leaves, are green ; 

 those on the ground in dry or rocky places are pale accordingly. 

 Grasshoppers generally have the prevailing hue of the fields where 

 they subsist. Indeed, protective coloration is very common, and any 

 person can find examples. 



More remarkable, however, is the protection afforded by what is 

 termed chromatic function. "It consists in the power possessed by 

 many fishes, crustaceans, amphibia, and reptiles, of adapting their gen- 

 eral coloring, often by extremely rapid alteration, to the coloring of 

 the surrounding objects, so that they seem to be helped by it in the 

 pursuit of their prey, or especially protected against the attacks of 

 their enemies." 



This is very striking in many fishes. It can be readily observed in 

 the common tree-frogs. The chameleon and the devil-fishes are famous 

 for their power of changing color when irritated. The degree of con- 

 sciousness involved in this is unknown. 



The resemblance to inanimate objects of many small animals, espe- 

 cially insects, is one of the most curious things commonly met with. 

 Insects imitate leaves, sticks, dry twigs, stones, lichens, etc., so per- 

 fectly as to sometimes deceive the close observer. The most remark- 

 able examples are found in the tropics, where insect-life luxuriates. 

 Wallace thus describes an Indian butterfly {Kallima) : " The upper 

 surface of these is very striking and showy, as they are of large size, 



