37^ Journal of Cojuparative JSl eiirology and Psychology. 



performed with Myrmica punctiventris Rog., Pheidole sp. ?, 

 Prenolepis imparis Say, Tapinoma sessilis Say and Formica fusca 

 var. subsericea Say. In each case the result was practically the 

 same as stated above. In many cases, on first reaching the un- 

 scented incline there would be a momentary hesitation as though 

 they had met an unfamiliar stimulus; but there was no prolonged 

 disturbance. In addition to these experiments with ants acting 

 in concert, similar experiments were tried with marked individuals 

 of Myrmica punctiventris Rog., and Formica fusca var. subsericea 

 Say. The results were the same. 



A slight variation of the above experiment was tried with the 

 same species of ants. Instead of substituting a new^ incline for 

 the old, the stage was revolved through an angle of 1 80 degrees and 

 the same incline retained in its original position. This gave an 

 unscented path from the pupae to the incline. With no, or, in 

 some cases, little hesitation the ants found the way to the incline. 

 Rarely would an ant go along the scented path instead of the un- 

 scented one that led to the incline. In these expermients where 

 ants worked in concert, two or three large spatulas of ants were 

 placed on the stage. Thus, where the colony was large, it was 

 highly improbable that all the ants would be conveying pupae at 

 the same time. Even after the experiment had been repeated 

 several times, the chances are that there would still be some ants 

 that had never made the trip. The ants that went along the path 

 that led away from the incline may have been ants that had not 

 yet learned the way. I also tried substituting a new stage for the 

 old. The results were the same as above. 



Now both Bethe's and Wasmann's hypotheses demand a 

 scented path over which ants must pass. The unscented path 

 down which these ants passed was twelve inches long. These 

 experiments do not prove that ants are unaffected by odors, nor 

 do they indicate that odors are not utilized by ants in finding 

 their way home; but they do demonstrate that the home-going of 

 ants is not controlled solely by the olfactory sense. They militate 

 against both Bethe's double polarized trail hypothesis and Was- 

 mann's assumption that the footprints have an odor-shape which 

 guides the ants home. The results of these carefully planned 

 experiments harmonize with observations made by myself and 

 others in the laboratory and field. 



Miss Fielde ('03) watched some specimens of Stenamma ful- 



