260 THE SENSE OF DIRECTION. 
again, as shown in Fig. 22; she returned after the usual 
interval, and went again straight to a ; then, after some 
Fig. 21. wanderings, to f, and 
at length, but only 
4 V4 after a lapse of 25 
7 minutes, found the 
4 food at g. These ex- 
4 4 periments were re- 
peated more than once, 
a and always with simi- 
Fig. 22. lar results. I then 
varied matters by re- 
«s moving the bricks, 
which, however, did not 
NS seem to make any dif- 
AS ference to the ants. 
f mma I thea accustomed 
a some ants (Lasivus ni- 
ger) to go to and fro over a wooden bridge, b,c (Fig. 23), 
to some food. 
Fig. 23. 
5 (a 
| | “ie 
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 atc, andcatb. In 
most cases the ant immediately turned round also; but 
even if she went on to b orc, as the case may be, as 
