36 Chapter 7. 



course, not so prominent with ants, whose queen 

 is much less of a center for the instinctive activi- 

 ties of the workers. With ants it is just the 

 workers that by their restless activity and the remark- 

 able display of individual initiative, are most power- 

 fully stimulating the instincts of their companions to 

 imitation, and thereby to actual co-operation in a given 

 work. The only difference between the baboons 

 described by Darwin and our ants is, that with the 

 former the instinctive communication between the 

 single individuals of a troop is effected mostly through 

 calls, with the latter, however, through taps of the 

 feelers. But both sometimes resort to more drastic 

 gestures to supplement their means of ^'communica- 

 tion." If an excited F. sangiiinea or fusca can not 

 succeed by taps of her feelers in inducing a companion 

 to join her work, she sometimes seizes her by the man- 

 dibles or by a leg and simply drags her to the object 

 which had first attracted her own attention. In the 

 same way an ant often protects her comrades from 

 a threatening danger first noticed by her. In my 

 observation nests I repeatedly noticed some F. san- 

 guinea or fusca, by taps of her feelers or some other 

 more drastic measures warning their companions to 

 be "on their guard." When, e. g., I took away the glass 

 tube connecting the feeding bulb with the top nest 

 (see diagram p. 23), and caught a few of the "senti- 

 nels" that instantly sallied forth from the opening of 

 the top nest ready to fight, I often remarked some ants, 

 that were posted near the opening of the top nest, 

 approaching the others, tapping them with their feelers 

 as a danger signal, and even getting hold of one, that 



