AUDITORY APPARATUS. Ixiii 



highly developed in the larval stao^e. The salivary 

 glands, as seen in Aphrophora, are drawn on Plate C. 



Palpi are wanting in Cicada3, but it is not improbable 

 that tactile sensations may come from the bulbous 

 hairs of the elytra, and even from the fine setae which 

 fringe the tibi«. 



The assiduous manner in which the insects comb and 

 brush off dust, clearly shows that their sensitiveness to 

 such matter is acute. 



That insects are sensible of something like hearing, 

 has been proved many times, and yet very little is 

 known of the channels by which sound passes on to 

 the nerve centres. So many insects produce sound, 

 either for tlieir own pleasure, as humming or buzzing; 

 or for that of their mates, like chirping ; that suitable 

 organs must exist to respond to air-vibrations. The 

 approach of a footstep, or the rustle of a bough, will 

 often stop a wdiole chorus of Cicadae for the moment; 

 but the chirping will begin again, as if by a signal, 

 after the cause of alarm has passed away. 



Carus, Burmeister,Durkheim, Shuckhard, and others 

 have assigned an auditory office to the antennae, 

 thinking that it is very unlikely that they can be only 

 tactile organs. The vibratory drums of the Cicada 

 have been already described as sound-producers ; yet, 

 merely as a suggestion, it may be thrown out, that as 

 the tympanum of the telephone receives as well as 

 transmits sound, so something analogous might 

 here happen with the Cicada drum. As, however, the 

 female has no visible drums, her auditory apparatus 

 must be of a different type, and must be sought 

 elsewhere. 



Soft articulating membranes at the bases of the 

 antennae of some crabs have been referred to the sense 

 of hearing ; and similar membranes placed on or below 

 the antennae of some insects, which can be rendered 

 more or less tense by the inflection of a joint, have 

 also been thought to have a like auditory office. 



An interesting stridulating organ has been found by 



