260 



THE SESSE OF DIRECTION. 



Fig. 21. 



a 



Fig. 22. 

 S 



again, as shown in Fig. 22 ; she returned after the usual 



interval, and went again straight to a ; then, after some 



wanderings, to /, and 

 at length, but only 

 after a lapse of 25 

 minutes, found the 

 food at g. These ex- 

 periments were re- 

 peated more than once, 

 and always with simi- 

 lar results. I then 

 varied matters by re- 

 moving the bricks, 

 which, however, did not 

 seem to make any dif- 

 ference to the ants. 



I then accustomed 

 some ants (Lasius ni- 



ger) to go to and fro over a wooden bridge, 6,c (Fig. 23), 



to some food. 



Fig. 23 

 I c 



i r i 



When they had got quite accustomed to the way, I 

 watched when an ant was on the bridge and then turned 

 it round, so that the end 6 was at c, and c at 6. In 

 most cases the ant immediately turned round also ; but 

 even if she weut op to 6 or c, as the case may be, as 



