The Ignorance of Instinct 193 



Experiment IV 



It is almost impossible to make certain whether 

 the Yellow-winged Sphex, who constructs 

 several cells at the end of the same passage and 

 stacks several Crickets in each, is equally 

 illogical when accidentally disturbed in her 

 proceedings. A cell can be closed though 

 empty or imperfectly victualled, and the Wasp 

 will none the less continue to come to the same 

 burrow in order to work at the others. Never- 

 theless, I have reason to believe that this Sphex 

 is subject to the same aberrations as her two 

 kinswomen. My conviction is based on the 

 following facts : the number of Crickets found 

 in the cells, when all the work is done, is usually 

 four to each cell, although it is not uncommon 

 to find only three, or even two. Four appears 

 to me to be the normal number, first, because 

 it is the most frequent and, secondly, because, 

 when rearing young larvae dug up while they 

 were still engaged on their first joint, I found 

 that all of them, those actually provided with 

 only two or three pieces of game as well as 

 those which had four, easily managed the 

 various Crickets wherewith I served them one 

 by one, up to and including the fourth, but 

 that after this they refused all nourishment, 



N 



