i88 ANIMAL LIFE 



surroundings had been eaten, chiefly by birds. Again, 

 it was found that where an animal, such as a wasp 

 or white butterfly, was boldly and aggressively coloured 

 it was often rendered comparatively immune to 

 attacks by some odour, taste, or sting. The gooseberry- 

 moth, caterpillar and chrysalis are barred with 

 black and yellow, and display their colours with as 

 much zeal as the wasp, and like it are distasteful. 

 The dominant Danaid butterflies of America and Africa 

 have an acrid taste, that is their defence, and they 

 display by bold, unmistakable colouration the warn- 

 ing of nauseousness. Further, it is by sailing under such 

 colours that a harmless and edible butterfly might gain 

 security. Such is the case. The marvellous instances 

 referred to in Poulton's work (p. 189), of similarity in 

 habit and colour between dominant butterflies and 

 their masquerading associates, are explicable when we 

 realise how instinctive the avoidance of such warning 

 colours has become. Yellow and black, black and 

 white, are danger signals, and give notice of con- 

 cealed poison. Such new significance thrown upon 

 the warning colouring of animals served to heighten 

 the protective value of sympathetic colouration. 



Such results have led observers to seek in protec- 

 tion the entire significance of cryptic colouring : to 

 regard the avoidance of enemies or the near approach 

 of prey as the reason for its existence ; whilst to 

 those who are not close observers the general vague 

 resemblance between animals and their surroundings 

 is illogically regarded as explicable for the same 



