2 ADELE M. FIELDE. 



determined by the odor of the mother latent in her egg, and the 

 odor of the father's mother latent in the spermatozoon. The 

 progressive odor therefore changes in each generation of females. 



d. The progressive odor manifest in female ants is the cause of 

 the separation of ants of the same species into hostile colonies, 

 and is of great advantage to the ants in their individual and their 

 communal life. 



3. The Incurred Odor. An ant may incur from its associates 

 an odor which is not inherent in itself, and which may be 

 removed by washing. It may be transferred from ant to ant 

 through air or through water. It arises from the substances 

 that give the specific odor and the progressive odor and that 

 create the nest-aura. 



II. RECENT EXPERIMENTS WITH THE PROGENY OF A SINGLE 

 QUEEN, COMPONOTUS PENNSYLVANICUS. 



In 1901 I found that the odor of working-ants of Stcnainma 

 fulvmn piccuin changes with their age, 1 forty days being the mini- 

 mum of time in which there occurs a change so great as to effect 

 the behavior of ants of the same colony toward one another at 

 their first meeting. 



In 1902 my further experiments indicated that a cause 2 for the 

 hostility of one colony toward another of the same species and 

 variety is a difference in odor coincident with difference in the age 

 of the colonies. 



In 1904 my observations on several species of ants, 3 represent- 

 ing three subfamilies, gave further evidence of their change of 

 odor with advance of age, and indicated that the odor of the queen 

 is unchanging, or that her odor changes much more slowly than 

 does that of the workers. 



1 have now had under observation for more than two years a 

 colony of Caniponotus pcnnsylvaniats, in which the assertion of a 



1( 'A Study of an Ant," Proceedings of the Academy of Natural Sciences of 

 Philadelphia, July, 1901, p. 449. 



2 " Notes on an Ant," Proceedings of the Academy of Natural Sciences of Phila- 

 delphia, September, 1902, p. 609 ; " Cause of Feud Between Ants of the Same 

 Species," BIOLOGICAL BULLETIN, Vol. V., No. 6, November, 1903, p. 328. 



3 " Power of Recognition Among Ants," BIOLOGICAL BULLETIN, Vol. VII., No. 

 5, October, 1904, p. 244. 



