266 INSECT ARTIZANS AND THEIR WORK 



The fact that these musical sounds are produced 

 only by the males in most of the Orthoptera as in 

 the Cicadas will prepare the reader for the further 

 statement that they are used in the courtship of 

 the insect, the whereabouts of the male being thus 

 advertised to the female as in the case of the Field 

 Cricket mentioned by Bates. There is reason to 

 believe that some species which appear to be with- 

 out musical calls of this character really have them, 

 though the notes they produce are not audible to 

 the human ear. The reason for this supposition 

 lies in the fact that such apparently dumb species 

 are provided, like the obviously musical ones, 

 with ears, situated in their hind bodies in this 

 family. 



Every field naturalist must know from his own 

 observation that there are people, apparently with 

 normal powers of hearing, to whom the fiddling of 

 a field full of grasshoppers makes no impression 

 upon their auditory organs ; and it is therefore 

 reasonable to suppose that there may be sounds 

 produced by insects that are not audible by the 

 most highly developed of human ears. The pos- 

 session of ears by an apparently dumb species is 

 good presumptive evidence that that species must 

 itself produce sounds. It should be noted, too, 

 that each species has its own particular notes, to 

 which, no doubt, its ears are specially attuned. 



On this point Scudder, speaking of North 

 American grasshoppers, says : "The uniformity with 

 which each species of Stenobothrus plays its own 



