390 yonrnal of Co?nparative Neurology and Psychology. 



TABLE II. 



Prenolepis imparts Say. Series 2. 



* This experiment furnishes a good example of the impossibility of predicting what an ant will do 

 when presented with a new problem. A worker spent several minutes wedging a pupa into the space 

 between the underside of the stage and the incline. Having succeeded it moved off; but in a few 

 moments returned, pulled out the pupa and carried it back to the stage. In less than two minutes it 

 returned and replaced the pupa in the crevice between the incline and stage. 



While this was going on, worker number two carried a pupa and laid it on the incline near the bottom. 

 One hundred and fiftv mm. higher up the incline it placed another pupa. Then, after carrying pupa 

 number two up and down the incline twice, it laid it on the incline thirty mm. higher than the first. 

 Likewise it placed a fourth pupa twenty mm. below the second. While doing so, it accidentally knocked 

 pupa number three off of the incline. It carried the fifth pupa down the stage to the nest, but in doing 

 so knocked another pupa off of the incline. This was the second pupa carried to the nest from the stage. 

 The pupa; that fell to the island were carried to the nest Ly stragglers from the nest. 



■j" These were working by incandescent light and at night; the two previous experiments had been 

 performed during the daytime. 



I While the ants were passing to and fro, the incline was so adjusted as to form a vertical gap about 

 five mm. high between the base of the incline and the Lubbock island. This did not disturb the ants in 

 the least. 



° One worker carried a pupa down incline A to the nest, all of the other pupae were carried down the 

 new incline B, which occupied the same position that incline A occupied at the time the ants learned 

 the way down it. One worker ascended incline A from the island and descended incline B with a pupa 

 which it carried to the nest. 



