HOW ANTS COMMUNICATE 



face and through the ground closure, to orient them- 

 selves, and make sense record for subsequent use as a 

 rudimentary sort of memory. 



It is this remarkable structure that so highly qualifies 

 the antennae for the function as the chief organ of com- 



Fig. 68 THE CHALLENGE WITH CROSSED ANTENNAE 



munication between ants. One cannot observe a colony 

 or a moving column of ants for any length of time with- 

 out seeing how constantly the crossed antennae are 

 used, obviously for communication. On the great dome 

 of the Alleghany mound-makers, and on their tree-paths 

 and the trails leading thereto, sentinels reach out their 

 antennae in challenge, and receive in the same way a 

 response. Two errant foragers meeting on the hunting- 

 field invariably cross antennae (Fig. 68). Going or com- 

 ing, leaving home or returning, on the city premises or 

 afield, it is always the same. One reads at once from 

 the manner the mutual "All right !" which passes. 

 Whether conveyed by odor or by contact or by both, 



151 



