The Yellow-wmged Sphex 73 



same experiment on the same Wasp ; her per- 

 sistency vanquished mine and her tactics never 

 varied. 



Having demonstrated the same inflexible 

 obstinacy which I have just described in the 

 case of all the Sphex-wasps on whom I cared to 

 experiment in the same colony, I continued to 

 worry my head over it for some time. What 

 I asked myself was this : 



* Does the insect obey a fatal tendency, which 

 no circumstances can ever modify ? Are its 

 actions all performed by rule ; and has it no 

 power of acquiring the least experience on 

 its own account ? ' 



Some additional observations modified this 

 too absolute view. Next year I visit the same 

 spot at the proper season. The new generation 

 has inherited the burrowing-site selected by the 

 previous generation ; it has also faithfully 

 inherited its tactics : the experiment of with- 

 drawing the Cricket yields the same results. 

 Such as last year's Sphex-wasps were, such are 

 those of the present year, equally persistent in 

 a fruitless procedure. The illusion was simply 

 growing worse, when good fortune brought me 

 into the presence of another colony of Sphex- 

 wasps, in a district at some distance from the 

 first. I recommenced my attempts. After two 

 or three experiments with results similar to 



