268 Animal Life and Intelligence. 



direction from which the sound conies. Hence, from the 

 position of the] antennae and the hairs, a sound would act 

 most intensely if it is directly in front of the head. 

 Suppose, then, a male gnat hears the hum of a female at 

 some distance. Perhaps the sound affects one antenna 

 more than the other. He turns his head until the two 

 antennae are equally affected, and is thus able to direct his 

 flight straight towards the female." 



It is difficult to determine the range of hearing in the 

 lower organisms. But it is quite possible, nay, very 

 probable, that the superior limit of auditory sensation is 

 much more extended in insects than it is in man. We know 

 that many insects, such as the cicadas, the crickets and 

 grasshoppers, many beetles, the death's-head moth, the 

 death-watch, and others, make, in one way or another, 

 sounds audible to us. But there may be many insect- 

 sounds — we may not call them voices — which, though 

 beyond our limits of hearing, are nevertheless audible to 

 insects. At the other end of the scale, on the other hand, 

 slow pulsations may be appreciated — for example, by 

 aquatic creatures — by means of what we term the auditory 

 organs, in a way that is not analogous to the sensation of 

 sound in us. It may be noted that auditory organs are 

 dotted about the body somewhat promiscuously in the 

 various invertebrates. We have seen that auditory organs, 

 or what are generally believed to be such, are found in the 

 foot of bivalves, in the antennules of lobsters, in the fore 

 legs of crickets and ants, in the abdomen of locusts, in the 

 balancers of flies, and in the tail of Mysis. But when we 

 come to consider the matter, there is no reason why the 

 organ of hearing should be in any special part of the body. 

 The waves of sound rain in upon the organism from all sides. 

 There is no great advantage in having the organs of hearing 

 in the line of progression, as with sight, where the rays 

 come in right lines ; nor in having them in close association 

 with the mouth, as in the case of the organ of smell. 



Closely connected with the organ of hearing in vertebrates 

 is the organ of another and but recently recognized sense. 



