58 Chapter II. 



Maerkelii, there was but one Dinarda hunter. Whilst 

 the rest remained perfectly passive towards the 

 Dinarda, this one ant immediately began an active 

 hunt. Had I not soon removed her from the small 

 nest, she would probably have aroused in her com- 

 panions the inftinct of imitation for a similar persecu- 

 tion, a fact which I have often observed. But by 

 removing this passionate hunter, I preserved friendly 

 relations between the other ants in the same experi- 

 menting nest (n sanguineas, 2 rufibarbis, 2 fusca) 

 and the Dinarda Maerkelii. In the greater observation 

 nest, from which I had taken these individuals, the 

 Dinarda hunt, which had begun with the killing of 

 Dinarda Maerkelii in March 1896, continued against 

 D. dentata until November of the same year, when the 

 ants gradually returned, but only for a short time, to 

 their former toleration of these guests. The resuming 

 of experiments in the following spring resulted finally 

 in the complete extermination of all the Dinardas in 

 that observation nest. During the following six years 

 I never succeeded in securing the existence of even a 

 single D. dentata in that nest, although in nature this 

 beetle is indifferently tolerated in all sanguinea nests! 

 The psychological importance of these phenomena has 

 been pointed out already in our discussion on the 

 different forms of learning in the animal kingdom. 1 



Another strange fact quite irreconcilable with the 

 "blind automatism" of instinct is the behavior of ants 

 regarding the number of Dinardas and other beetles, 



*) "Instinct and Intelligence," etc. (Herder, St. Louis, Mo., 1903), 

 p. 157. Also "Die psychischen Faehigkeiten der Ameisen" (Stuttgart, 

 1899), pp. 84, 88, 93. 



