POWER OF RECOGNITION AMONG ANTS. 247 



of stone fences, by repairing of the lane- road, and by my own dep- 

 redations. Ants so old as my three-year-olds have apparently 

 become almost unknown in the wild colony. 



The older the colony, the fewer would be the chances that any 

 ant, segregated as a pupa and always kept in isolation, would 

 find its own odor in any ant taken at random from the nest from 

 which said pupa had been taken. In August, 1904, I thus iso- 

 lated pupae and the ants hatched therefrom, and from among 

 many experiments made with them, I record the following as 

 typical : I isolated a pupa from the C colony wild nest, and when 

 the ant that hatched from it was eleven days old, never having 

 smelled any ant-odor other than that of its own body, I intro- 

 duced one by one to its Petri cell, where it was engrossed in the 

 care of introduced larvae, all the three-year-old ants to the num- 

 ber of twelve, all the two-year-old ants to the number of seven- 

 teen, all the one-year-old ants to the number of forty-two, and 

 seven C nest ants of precisely its own age, so that the number 

 of visitors arriving singly and at intervals amounted to eighty. 

 A period of repose was provided after the removal of one visitor 

 before another was introduced. Every one of these visitors was 

 at first meeting violently attacked by this callow, dragged away 

 from the larvae, and in some cases taken outside the Petri cell, if 

 I lifted its cover. Sometimes a visitor violently attacked the 

 resident callow, and she had to be rescued by me from sudden 

 death. In other like series of experiments with isolated callows 

 the resident callow sometimes found a congenial odor in a visitor 

 and willingly permitted her to share in the care of the larvae. 



Callows having their origin in different parts of the C colony 

 area behaved alike, and it appears improbable that all of those 

 tested could have been the product of eggs, larvae or pupae 

 brought in by raids on another colony, especially when the 

 greatness of the C colony is considered and its location studied. 



Other experiments with callows from this colony gave support 

 to my hypotheses. On July 1 1, 1904, there hatched in nest 3, 

 a pupa previously introduced by me from the C nest. I left 

 it seven days with the three-year-old ants, and then transferred 

 it to a Petri cell, giving it a few larvae to care for. This isolated 

 callow knew only its own odor, that of worker ants at least three 



