CHAP. IV Shifts for a Living 55 



caterpillars, the protective resemblance would be fostered 

 in the course of natural selection. 



Fig. S.— Moss insect. (From Belt.) 



8. Warning Colours. — While many animals are con- 

 cealed by their colouring, others are made the more 

 conspicuous. But, as the latter are often unpalatable or 

 dangerous, Wallace suggested that the colours were 

 warnings, which, as Poulton says, " assist the education 

 of enemies, enabling them to easily learn and remember 

 the animals which are to be avoided." Expressing 

 the same idea, Belt says, " the skunk goes leisurely along, 

 holding up his white tail as a danger-flag for none to come 

 within range of his nauseous artillery." So, the brightness 

 of the venomous coral-snake (Elaps) is a warning ; the 

 rattlesnake, excitedly shaking its rattle, " warns an intruder 

 of its presence"; the cobra " endeavours to terrify its enemy 

 by the startling appearance of its expanded hood and con- 

 spicuous eye-like marks." The language in which conspicu- 

 ous colours are described by many naturalists tends to 

 exaggerate the subtlety of animals, for the intentional 

 warning of possible molesters involves rather complex ideas. 

 Belt's description of the skunk, for instance, recalls a more 

 familiar sight — a cat showing fight to a dog — in regard to 

 which Mantegazza gravely tells us that the cat " bristles up 

 her fur, and inflates herself to appear larger, and to frighten 

 the dog who threatens her " ! In our desire to be fair to the 

 subtlety of animals, it is indeed difficult to avoid being 

 credulous. 



