32 Trans. Acad. Sci. of St. Louis 



to rely almost entirely upon odors for guidance; ants 

 which on their outward journey deposit odors on the trail 

 to make it more conspicuous. This, however, is not true 

 of the majority of ants for it is now well known that the 

 individuals of many species do not return home along the 

 identical trail by which they departed/ The two path- 

 ways are near together and roughly parallel but not coin- 

 cident. Then, too, the following easily repeated experi- 

 ments militate against such a conclusion : 



By means of a pin through its center, attach a rectangu- 

 lar piece of cardboard, eight inches square to the cork of 

 a bottle six or more inches high. By means of a narrow 

 cardboard inclined plane, connect this stage with the run- 

 way of a nest of ants with well developed eyes. On the 

 cardboard platform place a number of ants with their 

 eggs and pupae. At first the ants will rush about at 

 random as though lost. After a number of fruitless ef- 

 forts, they will finally find the way to the nest. Soon 

 there will be a procession of ants moving to and fro be- 

 tween the nest and the stage. AVhen the trail has been 

 well established, replace the inclined plane with a new 

 one and attach it to the opposite side of the platform. If 

 ants are guided home solely by odors stimulating trop- 

 isms, those ants should act as though confused and spend 

 much time learning the way home. Such will not be the 

 case. Without a moments hesitation the ants will jour- 

 ney homeward along the unscented pathway.* 



Arrange the card-board stage as above with the in- 

 clined plane upon the right. Near to the right and to the 

 left sides of the stage and separated from it by heat fil- 



5 Turner, C. H. The Homing of Ants. Jour, of Comp. Neur. and 

 Pay., Vol. 17, pp. 370-378. 



Cornetz, Victor. Trajets de Fourmis et Hetours au Nid. InsHtut 

 Gdndral Psychologique, M4nioires, No. 2, pp. 1-167. 



"Turner, C. H. Homing of Ants, ibid. pp. 399-401. 



