244 ^^^^ Hunting IVasps 



years ; then one day it suddenly appeared 

 before my eyes, offering a facility of examina- 

 tion and a clearness of detail that compensated 

 me for my long waiting. 



At the beginning of my investigations I was 

 twice enabled to witness the murder of the 

 caterpillar, and I saw, as far as the swiftness of 

 the operation permitted, the Wasp's sting applied 

 once and for all to either the fifth or the sixth 

 segment of the victim. To confirm this result, 

 I thought of ascertaining which ring had been 

 stabbed on caterpillars which I had not seen 

 sacrificed, but which I had taken from their 

 captors while they were being dragged to the 

 burrow. It was no use employing a magnifying- 

 glass, for no magnifying-glass enables one to 

 discover the least trace of a wound upon the 

 victim. The method adopted is the following : 

 when the caterpillar is quite still, I try each 

 segment with the point of a fine needle and thus 

 measure the amount of sensibility by the more 

 or less manifest signs of pain in the insect. 

 When the needle pricks the fifth segment or 

 the sixth, even piercing it right through, the 

 caterpillar does not stir. But if you prick 

 even slightly a second segment, behind or in 

 front of that insensible segment, the caterpillar 

 wriggles and struggles with a violence which 

 increases in proportion to the distance of the 



