250 A. M. FIELDE. 



hatched young, and probably strengthening as size increases 

 through the three inert stages of development ; the progressive 

 odor, that distinguishes the worker and changes or intensifies 

 with her advancing age ; and the specific odor which pertains to 

 the species or tribe. Adding to these perceptions the power of 

 recognizing familiar odors after a lapse of months or years, the 

 ant appears to be well equipped for life in her world. 1 If she 

 has not reason and imagination, she has at least the ground on 

 which to exercise both, cognoscence of past experiences. 



1 The organ discerning the nest-aura and probably other local odors lies in the 

 final joint of the antenna, and such odors are discerned through the air; the progres- 

 sive odor or the incurred odor is discerned by contact, through the penultimate joint ; 

 the scent of the track, by the antepenultimate joint, through the air ; the odor of the 

 inert young, and probably that of the queen also, by contact, through the two joints 

 above or proximal to those last mentioned ; while the next above these by contact 

 also discerns the specific odor. It is probable that the size of the queen determines 

 the amount of odor diffused by her. The amount of odor diffused by or discerned in 

 the larva; and pupce may be the determining factor in the assorting of the young ac- 

 cording to size, as is common among ants. The results of many experiments whereby 

 the function of many joints in the antennee were determined by me in 1901-1903 in 

 Stcnanima fuh'iiin are recorded in " Further Study of an Ant " and " Cause of P'eud 

 among Ants of the same Species," above referred to. The joints in the antennae 

 vary in different species, from four to thirteen. 



