A PRELIMINARY NOTE ON ANT BEHAVIOR. 33 



become scented by the foot-prints of the ants, in the place where 

 the new incline had been and placed a new unscented incline in 

 the place formerly occupied by the one the ants had been tra- 

 versing. Thus there was an unscented path in the position of 

 the old trail and the old familiar scented path was in a new 

 position. 



Now if ants are guided home solely by the sense of smell, they 

 should either have spent approximately as much time learning 

 the way down the new incline as they did before; or else, in their 

 random movements, they should have happened upon the scented 

 incline and gone down it. In reality, they did neither of these 

 things. They went almost immediately down the unscented in- 

 cline which occupied the position in space formerly filled by the 

 incline down which they had been carrying pupa; to the nest. 



Similar experiments, yielding the same results, were conducted 

 with marked individual ants. 



It will be seen at once that these experiments disprove not only 

 Bethe's double polarized trail hypothesis but also Wasmann's 

 assumption that their odor tracks have for ants an odor-shape 

 which guides them home. 



According to the current belief, ants going to and from my 

 stages should have followed the same path. But experiments, 

 conducted with marked individual ants, showed that this was not 

 always the case. I found : 



1. That the ant had to learn the way, not only from the stage 

 to the island, but also from the nest back again to the stage and 

 that it usually required more time to solve the second problem 

 than it did to solve the first. 



2. That sometimes an ant would regularly descend to the 

 island along the top side of the incline and ascend to the stage 

 along the under side of the same incline. 



3. I have noticed a worker regularly descend from the stage 

 by way of the incline and ascend the stage by way of its central 

 support. 



4. I have had ants ascend to the stage by way of one incline 

 and descend by the other. 



5. In passing from the nest to the foot of the incline the ant 

 did not always follow the same path. 



