IMPORTANCE OF SCENT. 



2.30 



then twisted as shown in Fig. 1 9. The bricks and tunnel 



being also rearranged so that they were exactly in the 



same direction as before, but the board having been moved, 



the line d e was now outside them. This change, however, 



did not ut all discom- Fig. 19. 



pose the ants ; but 



instead of going, as 



before, through the 



tunnel and between 



the rows of bricks 



to a, they walked 



exactly along the 



old path to . 



I then arranged 

 matters as before, 



but without the tunnel and with only three pairs of 

 bricks (Fig. 20). When an ant had got quite used to the 



Fig. 20. 



path d to , I altered 

 the position of the 

 bricks and food, as 

 shown in Fig. 21, mak- 

 ing a difference of 8 

 inches in the position 

 <>f the latter. The ant 

 came as before, walked 

 up to the first brick, 



t 'Uehed it with her antennae, but then followed her old 

 line to a. From there she veered towards the food, and 

 \ery soon found it. When she was gone, I altered ir 



1 



