1904.] NATURAL SCIENX'ES OF PHILADELPHIA. 647 



4. Workers deprived of both fiuiicles moved forward, backward or 

 turned side wise. 



5. Workers deprived of one antenna moved forward or turned side- 

 wise, as did the normal workers. 



6. Workers without antennae moved forward or backward or turned 

 side wise. 



It is thus evident that the antennae are not essential to the reactions 

 of these ants to vibrations from a solid, for the ants invariably reacted 

 irrespective of the conditions of the antennae, and the slight differences 

 in the nature of their reactions seem to us insignificant of the function 

 of hearing in parts removed. This opinion, that the antennae are not 

 essential to these reactions, is in accord with certain observations on 

 normal ants. When a normal ant in a Petri dish was resting with its 

 antennae high in air, it was olDserved to react vigorously to a slight 

 scraping on the edge of the dish, without, however, bringing the antennas 

 in contact with the dish. 



7. Decapitated queens and workers reacted by movements of the 

 legs, without, however, showing any determinate form of locomotion. 



8. Queens and workers deprived of their abdomens reacted by 

 moving forward or side wise. 



9. Queens deprived of any one pair of legs reacted by moving 

 forward, l^ackward or sidewise. 



10. Workers ■deprived of an}' one pair of legs reacted by moving 

 forward or turning sidewise. 



11. Queens and workers deprived of any two pairs of legs reacted by 

 making ineffectual efforts to walk, their direction of locomotion being 

 very irregular. 



It is thus evident that the reactions of the ants to the vibrations of 

 the underlying solid arc not dependent upon the antennae, head, abdo- 

 men, any pair or two pairs of legs. It seems to us probable that stimu- 

 lation is effected by the transfer of the vibration from the underlying 

 solid to the body of the ant, without reference to any special sense- 

 organ. That the various movements of the ants are true reactions, 

 and not merely motions transferred mechanicallv from the vibratino- 

 base to the body of the ant, as to any small particle capable of vibrating, 

 is seen from the fact that the body of a dead ant does not show these 

 movements, and further that in a live ant these movements cease after 

 the stimulus has been repeated a few times, but begin again after the 

 ant has been allowed a resting period of at least ten minutes. 



In none of our experiments was there any evidence of a directive 

 influence exerted by the stimulus on the movements of the ant. 



