The Yellow-winged Sphex 



ment on her arrival at the entrance. The 

 victim is once more dragged back to the edge 

 of the hole, but the Wasp always goes down 

 alone; and this goes on as long as my pa- 

 tience is not exhausted. Time after time, 

 forty times over, did I repeat the same ex- 

 periment on the same Wasp ; her persistency 

 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 experi- 

 ence 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 withdrawing the Cricket yields 

 the same results. Such as last year's Sphex- 

 wasps were, such are those of the present 

 77 



