THE PLASTIC BEIL-U'IOR OF AXTS. 535 



of other ants. Hence the ant's ability to distinguish between " friend " 

 and " enemy " does not depend on inherited reflexes, but on the sen- 

 sory perception of the olfactory impressions she receives during the 

 first days of her life as an imaginal worker." These facts have been 

 placed beyond doubt by the experiments of Forel, \Vasmann, Miss 

 Fickle, myself and others. The ease with which, as 1 have shown, 

 colonies will adopt adult queens of alien species, and the immediate 

 adoption of strange myrmecophiles by some of the ants observed by 

 \Yasrnann, show that reflexes are very far from offering a satisfactory 

 explanation of the facts and that we must suppose ants to be capable of 

 remembering odors and of regulating their behavior accordingly. 



3. Communication. \Ye are not surprised to find among both sci- 

 entific and lay observers a very general belief in the existence of some 

 pow'er of communication among ants, for the social organization of 

 these insects is alone sufficient to suggest such a belief. That it is of 

 long standing is shown by several passages in the ancient writers, and 

 by Dante's simile (Purg. xxvi, 34 ) : 



" Cosi per entro loro schiera bruna 

 S'ammusa 1'una con 1'altra formica, 

 Forse a espiar lor via e lor fortuna." 



I believe that no one who has watched ants continuously and under 

 a variety of conditions \vill doubt that they actually communicate with 

 one another. This is clearly indicated by the rapidity with which they 

 congregate on a spot where one of their number has found food, or 

 retire from any spot in which a few of their number have been killed 

 or injured. That there is often a desire on the part of ants to coerce 

 their companions into performing certain acts is shown by the way in 

 which they drag their queens about by the mandibles, or transport one 

 another bodily to new nests or back to the old nest. And the com- 

 pliance or obedience of the ants thus treated shows that they grasp the 

 meaning of this conduct on the part of their nest-mates. Forel, \Yas- 

 mann and myself have also interpreted the rapid antennary vibrations, 

 the minatory divarication of the jaws, the butting with the head, the 

 supplicatory posture of the body, the striking of the floor of the nest 

 with the gaster, etc., as so many signs which may be understood and 

 acted on by other ants. In Chapter XXYIII I gave some reasons for 

 concluding that stridulation, at least in the Myrmicinse and Ponerinae, 

 also serves as an important method of communication. I grant that 

 one is in very imminent clanger of falling into gross anthropomorphisms 

 in interpreting these various movements, but they are so clearly asso- 

 ciated with certain needs in the lives of ants and. moreover, meet with 

 such uniform response from other members of the colony, that they 



