68 A NATURALIST IN HIMALAYA 



certainly does follow back along the track of the 

 discovering ant, but if the finger be drawn across the 

 track so as to disturb the scent, then the swarm of 

 ants will be thrown into confusion. The line drawn 

 by the finger will form a regular barrier over which 

 the ants will cross with difficulty, or at which they will 

 lose their way and return to the nest. Members of 

 the issuing swarm, I have said, repeatedly communi- 

 cate with the discoverer, and they act thus, I believe, 

 because they are following the scent of the discovering 

 ant and wish to reassure themselves that they are on 

 the right scent by again testing the odour of the ant. 

 For this odour is a guide to the true road. 



FIG. i. Experiment with Communicating Ant. 



But a few simple experiments will confirm the 

 matter. If a dead insect be fixed to the top of a 

 stick standing erect on the ground, and a worker be 

 placed on the insect and then allowed to run down the 

 stick, return to the nest and inform the swarm of its 

 discovery, then the issuing swarm will have no diffi- 

 culty in finding the insect in this strange position. 

 But if, after the departure of the worker, the vertical 

 stick be replaced by another similar stick, then the 

 swarm will be thrown into confusion at the base of 

 the new stick owing to the scent being there lost. 



Now if F (Fig. i) be the discovered food, N the 

 nest and FN the returning path of the discovering ant, 

 and if, on that path at the point A, the ant be raised 

 from the ground and transferred to B, then the swarm 



