CAUSE OF FEUD BETWEEN ANTS OF THE SAME SPECIES. 327 



countered. It will also affiliate with any of her progeny of the 

 same age as itself, or with the progeny of her own sister of the 



same age. 



A difference of forty days in the ages of two ants produces a 

 difference of odor appreciable by the ants. If many pupae be 

 taken from one colony, and the workers hatched therefrom on 

 the same day be segregated ; and then, later on, more pupae be 

 taken from the same colony and the workers hatched therefrom 

 on the same day be likewise segregated and established in a nest 

 with inert young, the younger group of ants will not permit the 

 members of the older group to approach the young in their nest, 

 provided always that there be forty days or more of difference in 

 the age of the two groups. The degree of animosity exhibited 

 is in direct ratio to the difference in the age. 



An ant hatched in the first brood of a solitary queen associates 

 during its earliest days only with its queen and with its sister- 

 ants, all hatched in one summer. These workers know only 

 ants that are less than a year old, and will never become ac- 

 quainted in a friendly converse with ants older than themselves. 

 As seasons pass, and more ants are annually hatched from the 

 eggs of this queen or the queens among her offspring, the latest 

 comers know the odors of those of their own year, and of each 

 year gone by, up to that of the oldest in the common nest. One 

 might say that the sense of smell in the ant is more highly cul- 

 tivated if she live in an old community. 



I have been personally acquainted for four years with the ants 

 in a community, the C colony, whose domain is a hundred yards 

 in its diameter. On August 22, 1901, I took queens, males and 

 workers from the wild nest of this colony, and segregated a 

 similar group in each of two Fielde nests, where I kept them 

 two years. The queens were winged when captured, and were 

 doubtless less than a month old. The workers were fully colored, 

 and may have been a year or more older than the queens. No 

 young was permitted to hatch in either nest, and there was no 

 communication between the two nests nor with outside ants. 

 On August 25, 1903, I united the two groups, then numbering 

 four queens and twenty-five workers in one nest, and two queens 

 and nineteen workers in the other nest. They all affiliated in- 



