298 ENTOMOLOGY 



If instinct is blind, or mechanical, with no adjustment of means to 

 ends, then a pronounced individuality of action must signify something 

 more than instinct as in the case of the Ammophila. In regard to a 

 female Pompilus scelestus, which had dragged a large spider nearly to her 

 nest, the Peckhams observe: "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 remarkably 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 Hy- 

 menoptera have led some of the most critical students to ascribe intelli- 

 gence to these insects. The activities of the harvesting ants, the mili- 

 tary 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. Miss Enteman, on the con- 

 trary, says : " Wasps do not imitate one another. Instinct and individual 

 experience account sufficiently for their powers, and their apparent co- 

 operation is due entirely to the accident of their being born in the same 

 nest." She finds that the worker Polistes does not learn to feed the 

 larvae by imitating the queen. 



It is extremely difficult, however, if not impossible, 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, however, is due simply to a characteristic odor, which 

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

 receives hostile treatment from others of 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 

 behavior of insects is purely instinctive, .there is some reason to believe 



