ADELE M. FIELDE. 



dictated by memory, while that of the four minor workers was an 

 effect of hostility created by the presentation of an unfamiliar 

 odor. The major workers were either wanting in compassion, 

 or else they lacked means of communicating with their younger 

 sisters, for although they were each double the size of any minor 

 ant in the group, they did not interfere in behalf of the victim. 



The Nj. Group. - - The queen was transferred without eggs or 

 young to a new nest on July 14, 1904. She laid no eggs there- 

 after until December, 1904, and from the eggs then deposited the 

 five minor workers constituting the N4 group were hatched 

 between February 19 and March 23, 1905. These workers were 

 therefore four or five months old at the time of the experiment. 

 On July 16, 1905, I removed the queen from the nest, leaving the 

 five workers in charge of twenty larvae, the issue of the queen's 

 December eggs. Into this group of five minors, who had 

 never met older sisters, I introduced one of the majors from 

 group IS 3, now just a year old, and twice or thrice the bulk 

 of any of the five residents. The introduced ant was instantly 

 and violently attacked by three residents. This attack indicates 

 that the major, like the minor ants, like in shape and size as they 

 are to the queen, change their odor with advance in age, as do 

 minor workers. 



Having removed this visitor, I introduced a marked large 

 minor worker, fourteen months older than the residents, a sister 

 of theirs, hatched from eggs deposited by the queen in August, 

 1903. This visitor was likewise violently attacked, every one of 

 the five residents manifesting hostility to her, and the next day I 

 found her mangled body on their rubbish pile. 



The N$ Group. This group consisted of two minor workers, 

 the issue of the queen's December eggs, sequestered in their 

 cocoons and hatched on September 8, 1905. They were at 

 once placed in segregation in a new nest, with a few larvae and 

 cocoons from their mother's eggs. Ten days later these ants 

 drove away from their pile of young any member of the N4 

 group of sisters six months older than themselves. 



In these experiments it appears that it is the age of the work- 

 ers, not the age of the queen at the time when she deposits the 

 eggs from which the workers issue, that determines at any date 



