320 ENTOMOLOGY 



" presently she went to look at her nest and seemed to be struck with a 

 thought that had already occurred to us that it was decidedly too 

 small to hold the spider. Back she went for another survey of her 

 bulky victim, measured it with her eye, without touching it, drew her 

 conclusions, and at once returned to the nest and began to make it larger. 

 We have several times seen wasps enlarge their holes when a trial had 

 demonstrated that the spider would not go in, but this seemed a remark- 

 ably intelligent use of the comparative faculty." 



From the standpoint of pure instinct, indeed, much of the behavior 

 of the solitary wasps is inexplicable; while the actions of the social 

 Hymenoptera have led some of the most critical students to ascribe 

 intelligence to these insects. The activities of the harvesting ants, the 

 military or the slave-holding species, are of such a nature that the 

 possibility of education by experience and instruction is strong, to say 

 the least. In fact, Forel has maintained that a young ant is actually 

 trained to its domestic duties by its older companions. 



In his scholarly volume, Ants, Wheeler shows that these insects 

 have the ability to profit by experience, as exhibited in their foraging 

 and homing operations, the recollection of nest-mates and aliens, 

 communication, imitation and co-operation; and that they, have 

 memory in the general sense of the word, but that they have memory 

 images only as the result of sensory stimulation, and are unable to call 

 them up at will, much less to refer them to the absent or to the past. 

 "If this moderate estimate of the memory of ants be correct, it follows 

 that they must be incapable of reasoning of l focusing the wherefore/ 

 to use Lloyd Morgan's expression, for a mere association of sense impres- 

 sions is not deducing conclusions from premises." (Wheeler.) 



It is extremely difficult, if not impossible, however, to draw the line 

 between instinct and intelligence; and in doubtful cases there is a gen- 

 eral tendency to exaggerate the importance of intelligence rather than 

 that of instinct. For example, the well-known discrimination on the part 

 of ants between members of their own colony and those of other colonies, 

 even of the same species, would seem to imply intelligent recognition. 

 This recognition is due, however, to a characteristic odor, which 

 is derived from the mother of the community. An ant after being washed 

 receives hostile treatment from others in its own colony; while an alien 

 ant after being smeared with the juices of hostile ants is treated by the 

 latter as a friend. 



Each instance of apparent intelligence must be examined impartially 

 on its own merits. At present it may be said that, while most of the 



