The AmmophilcB 243 



median 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 independent of one 

 another : each of them exercises its influence 

 over its particular segment ; and its functions 

 are only very gradually affected by the derange- 

 ment of the adjoining segments. 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 difficulty 

 of observation is not small. The solitary 

 habits of the Ammophilge, their distribution one 

 by one over wide areas, the fact that one almost 

 always comes across them merely by chance : 

 all this makes it hardly possible to carry out 

 premeditated experiments with them, anymore 

 than with the Languedocian Sphex. You have 

 to be on the look-out a long time for an oppor- 

 tunity, to wait for it with untiring patience, 

 and to know how to profit by it at the very 

 moment when at last it presents itself, a 

 moment when you were not thinking of it. I 

 watched for that opportunity for years and 



