1901.] NATURAL SCIENCES OF PHILADELPHIA. 531 



The aptness of these ants to seek a new domicile whenever their 

 nest is disturbed is perhaps correlated with the necessity of main- 

 taining associations which give efficiency to a sensory memory. 



Three worker-ants, without kindred, have lived in one of my 

 Petri cells more than a year. They are perfectly at home in any 

 new similar cell to which I transfer them. This surely indicates 

 that they have become acquainted with their environment through 

 other senses than that of smell. 



Beside the scent whereby the ant lays her individual trail, every 

 Stenamma fulvum piceum has an odor manifest in all parts of her ani- 

 mate body, and discerned by herself and by other ants through the 

 eleventh segments of the antennae. 



It is improbable that the environment of the ants impart to 

 ih(nn iheir odor. I found beside an old stone fence a colony rear- 

 ing young under loose stones fifty yards apart. Workers taken 

 from the discovered extremes of this colonial manor affiliated per- 

 fectly. From a space no larger than a quart-pot I took thirteen 

 deiilated queens in September, and eleven more the following June. 

 Queens and workers of this colony met one another amicably after 

 a full year of separation, although the one had spent that time in 

 native soil, while the other had endured vicissitudes of travel, 

 living in a glass house, feeding on human confections, and drink- 

 ing water containing unlike mineral ingredients. I am also 

 acquainted with two colonies whose swarming exits are but two 

 yards apart, and these two colonies evince the intensest hostility to 

 one another. 



From among more than a hundred experiments that I have 

 madC; all yielding corroborative results in a study of the ant-odor, 

 I give but a few examples: 



The ant has an inherent odor. A callow five days old, that 

 had been isolated nine days before emergence from the pupa-stage, 

 was attacked and killed by the first ant it ever met, a callow of 

 another colony. 



Ants reared all the way from the larval stage without ant- 

 nurses attract or repel other ants. 



Ants were reared without ant-nurses, in sequestered groups, 

 from pup?e of the same colony. When these ants were twenty days 

 old the groups were united, and the ants at once affiliated. 



Young ants, reared in an alien group, were returned to their 



