Sensory Discrimination: The Chemical Sense 103 



odors may be produced by the influence of males that are 

 the offspring of worker mothers and have the differentiated 

 worker odor. A young ant isolated from the pupa stage 

 until many days old will single out its queen mother from 

 queens of other species, but will show decided suspicion 

 of older sister worker ants. A mixed nest formed of newly 

 hatched ants of different species was separated for seven 

 months. On rejoining each other, the ants showed hos- 

 tility ; their odor, Fielde argues, had changed. But young 

 ants of one species were received by those of the other 

 species. Fielde does not hesitate to introduce the psychic 

 factor and say that the latter remembered the odor of the 

 young ones, having been associated with it in their own 

 youth. The suggestion might be made that the young 

 ants had not as yet developed any specific odor, but this 

 is opposed by the observation that newly hatched Lasius 

 ants from a strange colony were not received by a nest 

 of Stenammas, while young Lasius ants from a colony with 

 which the Stenammas had been acquainted in youth were 

 accepted eleven months after the latter had been segregated. 

 It is an affair of the memory, Fielde is assured ; and she says, 

 " If an ant's experience be narrow, it will quarrel with many, 

 while acquaintance with a great number of ant odors will 

 cause it to live peaceably with ants of diverse lineage, pro- 

 vided the odors characterizing such lineage and age environ 

 it at its hatching" (224). Bethe held that an ant's own nest 

 odor offered no stimulus to it at aU, but that fighting reflexes 

 were occasioned by any foreign nest odor (51). Many 

 facts, however, seem to tell against this view; among 

 others, the early observation of Forel that a Myrmica 

 ant deprived of its antennae attacks everything in sight 

 (231). It should, according to Bethe's theory, live 

 peaceably with all. 



