254 ROMANCE OF THE INSECT WORLD CHAP. 



We now come to one of the most interesting 

 aspects of our subject, to one the discovery of which 

 admitted of our understanding many of the phenomena 

 that have gone before. Entomologists have been long 

 aware that certain butterflies belonging to widely 

 separated groups possess a strange close superficial 

 resemblance in shape and colour, a 

 resemblance in external parts but not 

 in essential internal structure, a re- 

 semblance that deceives, while natu- 

 rally the mimicking forms are unlike 

 those with which they have any real 

 affinity. The facts were familiar, but 

 no adequate explanation was forthcoming, they were 

 simply regarded as curious and inscrutable until 1862. 

 In that year Mr. Bates' wonderful memoir of the 

 Lepidoptera of the Amazon Valley solved the problem 

 which had been so long a puzzle, and gave impetus to 

 kindred investigation among groups of the Insecta 

 other than the Lepidoptera. Mr. Bates showed the 

 advantage that must be gained by a palatable and 

 nonprotected and hunted form if it imitated the con- 

 spicuous outward dress and habits of a species, of 

 whose inedibility these habits and conspicuousness 

 were certain tokens, and effectual safe-guards against 

 persecution and diminution of its numbers. The 

 cause of the existence of brilliant colour in butterflies 

 possessed of some attribute unpleasant to their enemies 

 being thus clearly recognised^ it was soon seen that 

 the same explanation applied to many other groups. 



The butterflies which are the objects of Mimicry 

 belong chiefly to the -two great families Danaidae and 



