604 PROCEEDINGS OF THE ACADEMY OF [Sept., 



an ant of a different subfamily from themselves. They had never 

 met any other ant of that subfamily. 



Experiment c. — Ofi the 23d of September, 1901, I put into an 

 artificial nest containing queens and workers of the C colony some 

 pupae of Formica Jmca subsericea, and on the 29th of September 

 one of these pu^^se hatched, and continued to reside with the 

 Stenammas, On the 20th of October I removed the Formica to a 

 Petri cell, which was cleaned weekly, and I kept her there uutil 

 November 24, thirty-five days, when I introduced to her cell two 

 queens and four major workers from the nest in which she had 

 been hatched. The Formica exhibited great fear, as these ants 

 usually do when brought into the presence of Stenammas ; but the 

 Stenammas appeared to be wholly friendly to the Formica. It is 

 possible that the Stenammas have a better memory than have the 

 Formicas, or it may be that her odor had continued to be manifest 

 in the nest of the Stenammas, modifying their action in regard to 

 their former associate. 



These Stenammas are very discriminating concerning the odor of 

 all ants introduced into their habitation, whether it be of their own or 

 other maternal lineage. — An example of the persistent aversion of 

 these ants toward the odor of an alien community was given by the 

 residents in two of my artificial nests. In nest M, ants of the C 

 colony, captured September 7, 1 900, had reared during the summer 

 of 1901 pupse introduced from the E colony, and had also reared 

 from the pupa-stage two Formica fusca subsericea. The fostered 

 Avorkers of the E colony remained in the nest; the two Formicas 

 were removed December 1, 1901. On the 6th of June, 1902, I 

 took all the ants, including queens and workers, in this nest and put 

 them into a similar artificial nest inhabited by queens aud" workers 

 of the C colony that had had no association with other ants since 

 their capture from the natural nest, August 22, 1901. There was 

 instant battle between the residents and the introduced ants, and 

 the fighting continued during the three following wrecks, until all 

 the ants reared from the E colony pup?e had been exterminated. 



In other nests, where no ants of alien lineage had been reared, 

 ants of the C colony immediately affilated after two years of sepa- 

 ration. That the colony odor and not personal acquaintance deter- 

 mines this affiliation may be illustrated by a single example. 



On August 14, 1902, I had an artificial nest where were many 



