The Modern Theory of Instmct 355 



of the particular nervous system and to the 

 number and grouping of the gangha. The 

 course of the sting is determined by the exact 

 anatomy of the victim. 



The particular prey of the Hairy Ammophila 

 is a caterpillar, each of whose nerve-centres, 

 which are distant one from the other and to 

 a certain extent independent in their action, 

 occupies a different segment of the insect. 

 This caterpillar, who is a very lively customer, 

 cannot be stored in the cell, with the Wasp's 

 ^g'^ upon his flank, until he has lost all his 

 power of motion. One movement of his body 

 would crush that egg against the wall of the 

 cell. 



Now the paralysis of one segment would not 

 mean that the next was also rendered incapable 

 of movement, because of the comparative inde- 

 pendence of the seats of innervation. It is 

 necessary, therefore, that all the segments, or 

 at least the most important, be operated on, 

 one after the other, from the first to the last. 

 The course which the Ammophila adopts is 

 that which the most experienced of physio- 

 logists would recommend : her sting is trans- 

 ferred from one segment to the next, nine 

 separate times over. 



She does better than that. The victim's 

 head is still unscathed, the mandibles are at 



