36 Trans. Acad. Sci. of St. Louis 



ciative memory. Two m.arked worker ants, A and B, 

 were being experimented upon at the same time. ''The 

 one I have called A readily learned the way down and up 

 the incline ; but to B this was an insoluble problem.** It 

 continued for a long time to move at random over the 

 stage, reaching down over first one edge and then over 

 another as though it was reaching for a support that was 

 not to be found, but nothing prompted it to pass down the 

 incline. Prompted by another thought, I shoved the sec- 

 tion lifter under the ant and transferred it to the island. 

 The ant then stepped off and carried the pupa to the nest. 

 As soon as B returned to the island, I shoved the section- 

 lifter under it and transferred it to the stage. B stepped 

 off and picked up another pupa. With the section-lifter 

 I again transferred it to the island. After this was re- 

 peated several times, the moment I presented the section- 

 lifter, whether on the island or on the stage, the ant im- 

 mediately mounted it and rested quietly thereon until it 

 had been removed to the stage or to the island ; then it 

 stepped off and picked up a pupa or else went into the 

 nest. I usually held the section-lifter from two to four 

 millimeters above the surface of the island or stage. In 

 this manner the industrious creature passed to and from 

 the stage about fifty times in something less than two 

 hours." 



At least two other investigators'" have succeeded in 

 teaching ants to do unexpected things. Since ants 

 possess associative memory and since they are easily dis- 

 concerted by changes made in the environment, it is not 



• Turner, C. H. The Homing of Ants, pp. 386-387, 



*0 Ernst, C. Einigc BcobachtunKcn and kilnstlichen Ameisennett- 



em Biol. Centrlb., vol 25, pp. 47-51; vol. 26, pp. 210-220. 



Wasmann. Die psycUisclien Fabigkcitcn dcr Amciscn. Zoologica, 



vol. 26. 



