The Making of Species 



on the ground amongst real dead leaves as a 

 remarkable instance of protective form and 

 colouration. And of course it may be that this 

 is the correct explanation. But what enemy is 

 this butterfly protected against ? Upon hundreds 

 of different occasions I have ridden and walked 

 through forests where Precis artexia was 

 numerous, and I have caught and preserved 

 many specimens of these butterflies, but never 

 once did I see a bird attempting to catch one 

 of them. Indeed, birds of all kinds were scarce 

 in the forests where these insects were to be 

 found." 



Similarly D. Dewar writes (Albany Review, 

 1907) : " If a naturalist be asked to cite a perfect 

 example of protective colouring, he will, as likely as 

 not, name the sand grouse (Pteroclurus exustus). 

 This species dwells in open, dry, sandy country, 

 and its dull brownish-buff plumage, with its soft 

 dark bars, assimilates so closely to the sandy 

 environment as to make the bird, when at rest, 

 practically invisible, at any rate to the human 

 eye. Unfortunately for the theory, this bird 

 stands less in need of protective colouration than 

 any other, for it has wonderful powers of flight. 

 Even a trained falcon is unable to catch it, 

 because it can fly upwards in a straight line as 

 though it were ascending an inclined plane, with 

 the result that the pursuing hawk is never able 

 to get above it to strike." 



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