Some Solitary Wasps of Texas. 19 



It is a significant fact Ammophila No> 72 picked up the 

 stranger's caterpillar and walked away with it when she did. She 

 had not yet dug the nest and therefore, according to Fab re, the 

 instinct to procure her prey should not have yet manifested itself. 

 This author experimented on Sphex ichneumonea which places her 

 grasshopper at the entrance to her nest and then runs in and out 

 again before dragging it down. He took advantage of a moment 

 when the wasp was out of sight below to move the 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, he concluded that 

 nothing less than the performance of a certain series of acts in a 

 certain order would satisfy her impulse. The Peckhams tried the 

 same experiments and found the American *S^. ichneumonae would, 

 after being fooled five or six times, carry the grasshopper inside in 

 various ways but without first running down. It is thus apparent 

 that wasps may perform certain instinctive acts though they be out 

 of the usual routine, as was the case with my Ammophila which 

 was about to procure the caterpillar before she had dug her nest. 



The stinging habit of Ammophila and the resultant condition 

 of the caterpillars have long been subjects of both the reason and 

 the imagination among naturalists. I here append my own ob- 

 servations on the condition of the caterpillars, A discussion of the 

 subject follows in the concluding chapter of this paper. 



Notes on the condition of Ammophila's caterpillars. 



I. No. 16. July 22d, 9 a. m., three small caterpillars, all re- 

 spond to stimulation, 



July 23d, 6 p. m., caterpillar containing egg dead, others still 

 alive, 



II. No. 28. August 17th, caterpillar responds to stimulation 

 at both ends of body, 



August 20th, more lively than on August 17th, 

 August 23d, it is nearly dead. 



III. No. 55. Egg laid 4 :50 p. m., September 1st. Caterpillars 

 move both ends of body spontaneously. 



September 3d, caterpillar passed foeces twice and is more lively 

 than the day before, moving front legs and posterior end of body 

 spontaneously. 



September 4th, 7 a. m., egg apparently hatched, larva occupying 



