NATURAL SELECTION 



either from below or else taking long strides up the funnel 

 again. Mr. Butler has observed lizards fight with and finally 

 devour humble bees, and a frog sitting on a bed of stone-crop 

 leap up and catch the bees which flew over his head, and 

 swallow them, in utter disregard of their stings. It is 

 evident, therefore, that the possession of a disagreeable taste 

 or odour is a more effectual protection to certain conspicuous 

 caterpillars and moths than would be even the possession of 

 a sting. 



The observations of these two gentlemen supply a very 

 remarkable confirmation of the hypothetical solution of the diffi- 

 culty which I had given two years before. And as it is generally 

 acknowledged that the best test of the truth and complete- 

 ness of a theory is the power which it gives us of prevision, 

 we may, I think, fairly claim this as a case in which the 

 power of prevision has been successfully exerted, and therefore 

 as furnishing a very powerful argument in favour of the 

 truth of the theory of Natural Selection. 



I have now completed a brief, and necessarily very im- 

 perfect, survey of the various ways in which the external form 

 and colouring of animals is adapted to be useful to them, 

 either by concealing them from their enemies or from the 

 creatures they prey upon. It has, I hope, been shown that 

 the subject is one of much interest, both as regards a true com- 

 prehension of the place each animal fills in the economy of 

 nature, and the means by which it is enabled to maintain that 

 place ; and also as teaching us how important a part is played 

 by the minutest details in the structure of animals, and how 

 complicated and delicate is the equilibrium of the organic 

 world. 



My exposition of the subject having been necessarily 

 somewhat lengthy and full of details, it will be as well to 

 recapitulate its main points. 



There is a general harmony in nature between the colours 

 of an animal and those of its habitation. Arctic animals are 

 white, desert animals are sand -coloured ; dwellers among 

 leaves and grass are green ; nocturnal animals are dusky. 

 These colours are not universal, but are very general, and are 



