POWERS OF COMMUNICATION. 169 



friction of my finger ; on the other hand, the bridge 

 (d) had retained the scent, but was so placed as to 

 lead away from the larvae ; and, under these circum- 

 Btances, out of 41 ants which found their way towards 

 the larvae as far as e, 14 only passed over the bridge / 

 to the larvas, while 27 went over the bridge d to the 

 empty glass m. 



Taking these observations as a whole, 150 ants 

 came to the point e, of which 21 only went on to the 

 larvae, while 95 went away to the empty glass. These 

 experiments, therefore, seem to show that when an 

 ant has discovered a store of food and others flock to 

 it, they are guided in some cases by sight, while in 

 others they track one another by scent. 



I then varied the experiment as follows : — I put an 

 ant {L. niger) to some larvae as usual, and when she knew 

 her way, I allowed her to go home on her own legs ; but 

 as soon as she emerged from the nest, if she had any 

 friends with her, I took her up on a bit of paper and 

 carried her to the larvae. Under these circumstances very 

 few ants indeed found their way to them. Thus, on June 

 23, 1876, at 5.30, an ant which had been previously 

 under observation was put to some larvae. She took 

 one and returned as usual to the nest. At 5.34 she 

 came out with no less than 10 friends, and was then 

 transferred to the larvae. The others wandered about a 

 Uttle, but by degrees returned to the nest, not one of 

 them finding their way to the larvae. The first ant 

 picked up a larva, returned, and again came out 



