134 THE COLOURS OF ANIMALS 



golden appearance at a still earlier period. The»e can 

 be no doubt of this, for Aristotle's word is 'x^pvaaXkls, 

 identical with our own ; nor can there be any doubt 

 as to the stage of insect life to which Aristotle was refer- 

 ring, for his language is precise and descriptive. In 

 fact, if a naturalist wished to convey to any one igno- 

 rant of the changes undergone in insect metamorphosis 

 a short and simple but perfectly accurate account of 

 the two first stages of a Lepidopterous insect, he could 

 not do better than use the very words of Aristotle: 



* Caterpillars take food at first, but afterwards they 

 cease to take it and become quiescent, being generally 

 called chrysalides ; ' * or again in another passage : 



* Afterwards the caterpillars, having grown, become 

 quiescent, change their shape, and are called chrysa- 

 lides.' 2 



Mr. T. W. Wood suggested that the metallic 

 appearance was so essentially unlike anything usually 

 found in the organic kingdoms, that it acted as a 

 protection to the organisms possessing it. Others 

 have thought that it has the value of a warning 

 colour, indicating an unpleasant taste (see Chapter 

 X.). It is probable that the appearance sometimes 

 bears this meaning now, but it is unlikely that such 

 was its original use ; for the fact that metallic colours 

 can be called up or dismissed by the appropriate sur- 



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