1902.] NATURAL SCIENCES OF PHILADELPHIA. 603 



times. On the 24th of November, after fifty days of separation, I 

 put the Stenammas, now only two in number, into a clean cell, and 

 introduced the Formica. The Formica was ii| as complete a panic 

 as could have been one of its kind that had never seen a Stenamma. 

 She ran from the Stenammas, snapped at them when forced into 

 proximity, and gave starts of terror when coming inadvertently 

 into touch with them. The Stenammas, on the contrary, showed 

 neither fear nor dislike of the big foster-child that had been 

 returned to them. The fear manifested by the Formica gradually 

 diminished, and after about two weeks together the Formica would 

 voluntarily approach and touch antennae with the Stenammas. 



1 then took two Stenammas of the same size and lineage as these 

 fostering ants, placed them in conditions in all respects similar, and 

 introduced this same Formica to their cell. The Stenammas at 

 once attacked the Formica, and would have slain her had I not 

 intervened. I then returned her to the fostering ants, and left her 

 with them one week longer. 



I then repeated the separation of the two Stenammas and the 

 Formica, again keeping them apart fifty days, and likewise clean- 

 ing the two cells once a week. On February 5, 1902, I again 

 reunited the three ants, and this time found that the memory of 

 each species for the other appeared to be perfect. There was no 

 manifestation of fear nor repulsion on eiiher side. Perhaps the 

 increased age of the Formica, or her longer residence with the 

 Stenammas previous to the second test enabled her to better remem- 

 ber them. She died a natural death the 10th of February. 



In order to ascertain the existence of fighting qualities in these 

 two Stenammas, I put into their cell aliens of their own species 

 and found that they retained the habitual aversion of their kind 

 toward strangers. 



On the 11th of June, 1902, the same two Stenammas, then 

 much engrossed in the care of pupse, fiercely attacked Wood's 

 Hole Formica fusca subsericea that I introduced into their cell. 

 This Formica was not of the same colony as the one that they had 

 fostered. 



These two Stenammas seem to have remembered for fifty days 



soap in hot water, soaking in boiling water, and rinsing in running 

 water. A full description of the cells used in these experiments may be 

 found in "A Study of an Ant," Proceedings of the Academy of Natural 

 Sciences of Philadelphia, July, 1901. 



