216 WASP STUDIES AFIELD 



so that one might suspect that the wasp were here impro- 

 vising a tool with which to tamp down the sand." 



Considering that our tool-using insect described above 

 would have nothing to do with the pebble until a time 

 when it was needed for tamping, and in view of what is to 

 follow as the result of very close observation by the two of 

 us on another pictipennis mother closing her nest, we do 

 think that they actually have highly plastic intellectual 

 powers. Morgan says, 4 in speaking of the interesting ob- 

 servation of the tool-using Ammophila of the Peckhams : 

 "Here we have intelligent behavior rising to a level to which 

 some would apply the term rational, for the act may be held 

 to afford evidence of the perception of the relation of the 

 means employed to an end to be attained, and some general 

 conception of purpose." But Holmes takes exception to 

 this interpretation of Morgan by saying: "But in estimat- 

 ing the psychic aspect of the performance we must bear in 

 mind that the act is one which borders closely upon the 

 normal instinctive behavior of the insect. The seizure of 

 pebbles in the mandibles and the packing in of dirt are parts 

 of the instinctive process of filling the hole. The wasp com- 

 bines two features of its hole-filling instinct in a rather un- 

 usual way. Does she really perceive the relation of means 

 to end? I am not sure that she does." Whether Morgan's 

 or Holmes' interpretation is the correct one we hope the 

 details given below will convince the reader. In this con- 

 nection it may not be amiss to relate exactly the conduct of 

 another of these wasps, through this part of her task. 



The wasp, when discovered, was carrying her caterpillar. 

 It was a smaller worm than usual so small that she car- 

 ried it in her mandibles by grasping it in its middle, and 

 lifting it clear off the ground, so she could use all her legs 

 freely for progression. She made a pretty sight carrying 



4 Holmes, The Evolution of Animal Intelligence, p. 204. 1911. 



