HOW A.XTS COMMUNICATE 



from the ear. The male and soldier, to be heard, must be 

 held somewhat closer, and the worker-majors still closer. 

 The smaller workers and minims, though stridulating, 

 as may be seen from the movements of the abdomen on 

 the post-petiole, are quite inaudible to the human ear. 

 We may safely join in the inference that "it is not at 

 all improbable that all this differentiation in pitch, 

 correlated as it is with a differentiation in the size and 

 functions of the various members of the colony, is a very 

 important factor in the co-operation of these insects, 

 and of ants in general. " [W. 4, p. 11.] 



Such a condition, of course, implies that this stridula- 

 tory language is "heard" -that is, produces an effect 

 analogous to that of hearing. No auditory organs have 

 yet been discovered in ants with such positiveness as to 

 establish their existence beyond question, although 

 minute bodies within the tip of the antennre are believed 

 by some observers to serve as such in part. But that 

 their behavior under certain conditions is quite con- 

 stantly precisely what one would expect were ants known 

 to have ears, or their equivalent, is easily seen. Whether 

 they hear or not, they respond to sounds in a way cor- 

 responding to the acts of creatures that have ears, and 

 do undoubtedly hear. It is manifest that this must 

 have a vital effect upon the government of ant communes 

 to which, as in all other governments, some means of 

 intercommunication are essential. 



Last of all, and perhaps most important of all, as a 

 means of intercommunication, is antermal language. 

 Ants, in common with most insects, are provided with a 

 pair of peculiar organs known as antennne, located upon 

 the face, above the mouth and midway bet \veen the eyes. 

 Externally these are thread-like rods of greater or less 



147 



