The Modern Theory of Instinct 357 



The Hairy Ammophila has twice allowed me 

 to attend her surgical operations. I have de- 

 scribed in an earlier chapter of this volume my 

 first observation, which dates many years back. 

 On that occasion I witnessed the performance 

 quite unexpectedly ; to-day, I have made all 

 my preparations and have plenty of time at my 

 disposal, so that I am able to make a much more 

 thorough observation. In each case there was 

 a multiplicity of needle-pricks, which were dis- 

 tributed methodically, from front to back, along 

 the ventral surface. Is the number of stings 

 indeed identical in both cases ? This time, it 

 is exactly nine. In the case of the victim which 

 I saw paralysed on the Plateau des Angles, it 

 seemed to me that the weapon inflicted more 

 wounds, though I am not able to state the 

 precise number. It is quite possible that 

 this number varies slightly and that the last 

 segments of the caterpillar, being much less 

 important than the others, are attacked or left 

 alone according to the size and strength of the 

 quarry to be incapacitated. 



On the second occasion, moreover, I had 

 my first view of the squeezing process to which 

 the caterpillar's brain is subjected, a process 

 that produces the torpor which makes the 

 transport and storage of the victim possible. 

 So remarkable a fact would not have escaped 



