260 



THE SENSE OF DIRECTION". 



Fig. 21. 

 T. 



agaiu, 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, b,c (Fig. 23), 



to some food. 



Fig. 23 

 i c 



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 b was at c, and c at 6. In 

 most cases the ant immediately turned round also ; but 

 even if she went on to b or c, as the case may be, as 



