A Scientific Slaughterer 47 



the median line of the lower surface, that the 

 Wasp inserts her dirk. By what expert in- 

 stinct is she inspired ? 



To select, as the spot wherein to drive her 

 sting, the one vulnerable point, the point which 

 none save a physiologist versed in insect 

 anatomy could determine beforehand : even 

 that is far from being enough. The Wasp has 

 a much greater difficulty to surmount ; and 

 she surmounts it with an ease that stupefies us. 

 The nerve-centres governing the locomotory 

 organs of the insect are, we were saying, three 

 in number. They are more or less distant 

 from one another ; sometimes, but rarely, they 

 are close together. Altogether they possess a 

 certain independence of action, so that an in- 

 jury done to any one of them induces, at any 

 rate for the moment, the paralysis only of the 

 limbs that correspond with it, without affecting 

 the other ganglia and the limbs which they 

 control. To strike in succession these three 

 motor centres, each farther back than the one 

 before it, and to do so between the first and 

 second pair of legs, seems an impracticable 

 operation for such a weapon as the Wasp's 

 sting, which is too short and is besides very 

 difficult to guide under such conditions. It is 

 true that certain Beetles have the three ganglia 

 of the thorax very near together, almost touch- 



