Masterpieces of Science 



seure. The moths on the contrary have gen- 

 erally their chief colour on the hind wings 

 only, the upper wings being of dull, sombre, 

 and often imitative tints, and these generally 

 conceal the hind wings when the insects are 

 in repose. This arrangement of the colours is 

 therefore eminently protective, because the 

 butterfly always rests with his wings raised 

 so as to conceal the dangerous brilliancy of his 

 upper surface. It is probable that if we watched 

 their habits sufficiently we should find the under 

 surface of the wings of butterflies very fre- 

 quently imitative and protective. Mr. T. W. 

 Wood has pointed out that the little orange-tip 

 butterfly often rests in the evening on the green 

 and white flower heads of an umbelliferous 

 plant, and that when observed in this position 

 the beautiful green and white mottling of the 

 under surface completely assimilates with the 

 flower heads and renders the creature very 

 difficult to be seen. It is probable that the rich 

 dark colouring of the under side of our peacock, 

 toxtoiseshell, and red-admiral butterflies answers 

 a similar purpose. 



Two curious South American butterflies that 

 always settle on the trunks of trees (Gynecia 

 dirce and Callizona acesta) have the under 

 surface curiously striped and mottled, and 

 when viewed abliquely must closely assimilate 

 with the appearance of the furrowed bark of 

 many kinds of trees. But the most wonderful 

 and undoubted case of protective resemblance 

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