The Ammophilae 



the other, to suppress all movement in her 

 Crickets. Instead of a solitary centralized 

 point or of three nerve-nuclei, the cater- 

 pillar has twelve, separated from one an- 

 other by the distance between one segment 

 and the next and arranged like a string of 

 beads on the ventral surface, along the me- 

 dian line of the body. Moreover, as is the 

 general rule in the lower animals, where the 

 same organ is repeated a great number of 

 times and loses power by its diffusion, these 

 different nerve-centres are largely independ- 

 ent of one another: each of them exercises 

 its influence over its particular segment; and 

 its functions are only very gradually affected 

 by the derangement of the adjoining seg- 

 ments. One of the caterpillar's rings can 

 lose its power of moving and feeling and the 

 remainder will nevertheless remain capable 

 of both for a considerable time. These 

 facts are enough to show the great interest 

 attaching to the methods of slaughter which 

 the Wasp adopts with her prey. 



But, while the interest is great, the diffi- 

 culty of observation is not small. The soli- 

 tary habits of the Ammophilas, their distri- 

 bution one by one over wide areas, the fact 

 that one almost always comes across them 

 263 



