INTELLIGENCE IN INSECTS 201 



concludes, "can only be explained by an association of space 

 form and color memories with memories of taste." 



We are certainly justified in concluding that bisects are 

 not mere reflex machines incapable of learning by experience. 

 They can form associations very quickly in many cases. 

 They give evidence of memory. They have a remarkable 

 ability for retaining impressions of topographical relations. 

 We may not be compelled to admit that they have ideas, 

 but it must be granted, I think, that a wasp which after 

 cutting a caterpillar in two and carrying away one part, 

 came back and searched diligently for the remainder, re- 

 tained somehow an impression of the missing part and its 

 location. If out of sight it was not out of mind. The hunt- 

 ing of the wasp is instinctive and when we see a wasp 

 flitting about here and there in a feverish search for prey 

 we cannot assume that it carries in its mind an image of the 

 object of its pursuit. But the case is different with a wasp 

 which has secured its prey and comes back to find it. The 

 prey and its position are represented by some sort of "en- 

 gram" in the nervous center of the wasp, which is formed 

 by the various stimuli, optical, olfactory and tactual, which 

 resulted from the encounter. If the wasp does not have an 

 idea of its prey it has something which plays a role similar 

 to that of ideas in ourselves. As the wasp when it has 

 disposed of the second moiety of the caterpillar no longer 

 returns, its mental content is evidently changed by having 

 carried the part to its nest. If there is something represent- 

 ing "part-of-caterpillar-among-leaves" that leads the wasp 

 on its hunt, we may conclude that there is also something 

 corresponding to " part-of-caterpillar-now-in-nest " which 

 prevents further search. 



I realize that one is on treacherous ground in trying to 

 interpret the workings of the insect mind. Forel, whose 



