32 THE SOLITARY WASPS. 



other genera), and that to sting a certain segment being found 

 the most successful method, this habit was inherited like the 

 tendency of a bull dog to pin the nose of a bull, or of a ferret to 

 bite the cerebellum ; and that the next step in advance was to 

 prick the ganglion only slightly, thus giving the larvae fresh 

 instead of dried meat.* It seems to us more probable that we 

 have in these instincts examples of the action of natural salec- 

 tion, the primary advantage of the use of the sting being to re- 

 duce the prey to helplessness. Our AmmopJiila, with their 

 many-ganglioned caterpillars, have been carried some steps fur- 

 ther, and if, as may be possible, those larvae which have pro- 

 vided for them caterpillars that cannot move and that yet are 

 alive and fresh, derive any advantage from these conditions, 

 the present variable state of things may merge into one in which 

 the instinct will be better adjusted, approaching and perhaps 

 finally reaching that which Fabre finds in the species which he 

 has observed; but at present, speaking for A. urnaria, we may 

 say that this instinct, wonderful, complex and difficult to ex- 

 plain as it unquestionably is, is still far from being exact, either 

 in its methods or in the results obtained. 



*Life and Letters, Vol. II., p. 420. 



