Turner, Homing of Ants. 375 



both ants and pup^E, larvae or eggs were replaced on the stage. 

 After this had been repeated several times, so as to make sure that 

 the ants were thoroughly acquainted with the trail, the incline 

 was reversed, so as to place the original nest-end at the stage, 

 and the stage-end near the nest. Although this was tried 

 several dozen times, and with all the species used in the experi- 

 ments on heliotropism, the ants continued as though nothing had 

 happened. At first I was inclined to think that these experiments 

 disprove Bethe's contention, but a little reflection showed that 

 they do not; for, if there is a double polarized trail one path of 

 which leads the ants to the nest and the other from it, reversing 

 the incline would still leave a double polarized trail of the same 

 functional type. 



This failure to reach a solution led to a different type of experi- 

 ment. As in the first series, a cardboard stage from which an 

 incline led down to the island was used. A great many pupae, 

 larvae or eggs, and workers were placed on this stage. After these 

 burdens had all been carried to the nest, they, with several workers, 

 were replaced on the stage. In a shorter time than before the pupae 

 were all carried by the workers down the incline to the nest. This 

 was repeated until I thought the ants were thoroughly acquainted 

 with the stage and incline; then a second incline was so placed as 

 to lead from the opposite side of the stage to the Lubbock island. 

 If, after the lapse of a few minutes, no worker descended this sec- 

 ond incline, I concluded that the ants were thoroughly acquainted 

 with the path down the first incline to the nest. If they proved 

 to be acquainted with the path, I then placed the first incline, 

 which had become scented by the passing to and fro of the ants, 

 where the unscented one had been and placed the unscented incline 

 in the place formerly occupied by the scented one. Thus there 

 was an unscented path in the place of the old trail and the old 

 scented path was in a new position. Now if ants are guided 

 home solely by the sense of smell, then one of two things should 

 happen: they should spend approximately as much time learning 

 the way down the new incline as they did learning the way down 

 the former; or else, in their random movements, they should 

 happen upon the scented incline and go down it. In reality they 

 did neither of these things. They almost immediately went down 

 the unscented incline which occupied the former position of the 

 scented incline. About a hundred experiments of this sort were 



