INSTINCT OR REASON? 
G. W. AND E. G. PECKHAM. 
IN our work on the instincts of solitary wasps! we included 
among the true instincts the way in which the wasp acts after 
bringing her prey to the nest, and gave as an example the 
habit of Sphex ichneumonea in placing her grasshopper at 
the entrance to the tunnel and then running in and out again 
before dragging it down. We also referred to the experiment 
of Fabre on a Sphex, in which he took advantage of the moment 
that the wasp was out of sight below to move her prey to a 
little distance, with the result that when the wasp came up, she 
brought her cricket to the same spot and left it as before, while 
she visited the interior of the nest. Since he repeated this 
experiment about forty times, and always with the same result, 
it seemed fair to draw the conclusion that nothing less than the 
performance of a certain series of acts in a certain order would 
satisfy her impulse. She must place her prey just so close to 
the doorway ; she must then descend and examine the nest, 
and after that must at once drag it down, any disturbance of 
this routine causing her to refuse to proceed. We recently 
found a Sphex ichneumonea at work storing her nest, and thought 
it would be:interesting to pursue Fabre’s method and find out 
whether she were equally persistent in following her regular 
routine. We allowed her to carry in one grasshopper to estab- 
lish her normal method of procedure, and found that, bringing 
it on the wing, she dropped it about six inches away, ran into 
the nest, out again, and over to the grasshopper, which she 
Straddled and carried by the head to the entrance. She 
then ran down head first, turned around, came up, and, seiz- 
ing it by the head, pulled it within. On the following day, 
when she had brought the grasshopper to the entrance of the 
nest, and while she was below, we moved it back five or six 
1 Instincts and Habits of the Solitary Wasps, p. 232, 1898. 
817 
