432 'Jouriial of Comparative Neurology and Psychology. 



left sides of the stage. Behind the heat-filter on the right was placed a 32 c.p. incandescent lamp. 

 Excepting for this light the room was dark. 



A. Placed a new white incline on the opposite side from the first incline. 



B. While the worker was on the stage the 32 c.p. lamp was placed behind the heat-filter on the side 

 where the second incline was. 



C. While the worker was in the nest the light was replaced on the same side as the first incline. 



D. While the worker was on the stage I substituted a new white incline for the old. In doing so 

 the stage was jarred considerably. 



E. Do. White for black. 



F. Replaced the worker on the stage. 



G. While the worker was on the island, I substituted a white incline for the black. 

 H. Do. New white for the old. 



Fig. 13. Learning-curve of an individual Myrica punctiventris, illustrating one of those occasional 

 cases in which it took the ant much longer to make the second trip to the nest than it did to make the first. 



Apparatus, two cardboard stages, each with an incline leading down to the island. Pupae are placed 

 on both stages. The marked worker is placed on stage number one. 



