POWERS OF COMMUNICATION. 167 



tbe larvae ; but only one passed over the little bridge to 

 the larvae, while 15 went over the bridge L to i. On 

 repeating this experiment with another marked ant, she 

 herself made 40 journeys, during which 19 other ants 

 found theu- way to the point of junction. Only 2 went 

 over the little bridge to the larvae, 8 went over L to i, 

 and the remainder on to D. 



In another similar experiment the marked ant made 

 16 journeys; and during the same time 13 other ants 

 came to the point of junction. Of these 13, 6 went 

 on to D, 7 crossed over L to i, and not one found the 

 larvjE. Thus altogether, out of 92 ants, 30 went on to 

 D, 51 crossed over in the wrong direction to i, and only 

 11 found their way to the larvae. 



From January 2 to January 24 (1875) I made a 

 series of similar observations; and during this time 56 



ants came in all. Of these, 20 went straight on to 



D, 26 across the paper to i, and only 

 10 to the larvae. 



This, I think, gives strong reason to 



conclude that, under such circumstances. 



ants track one another by scent. 



I then slightly altered the arrange- 

 ment of the papers as shown in the 



accompanying diagram (fig. 4). a, as 



before, is the nest, o being the door. 



B is the board ; h is a, glass on which 



are placed the larvae ; m is a similar glass, hut empty } 



n a strip of paper: to the end of n are pinned Ijto 



