NERVES SENSES : HEARING. 305 



certain organs for their express emission. The Linneean 

 genera Gryllus and Cicada comprise the only insects thus 

 circumstanced, and which are confined to the males. The 

 death's-head moth also 

 produces a plaintive kind 

 of cry ; and another kind 

 of noise is produced by 

 the death-watch (Anobi- 

 um striatum], hy heating 

 the front of its head 



Death-watch, natural size and magnified. 



against the surface upon 



which it is stationed. Swift thus satirically alludes to this 

 insect : 



" A wood-worm, [beetle] 



That lies in old wood, like a hare in her form, 



With teeth or with claws it will bite or will scratch, 



And chambermaids christen this worm a Death-watch, 



Because, like a watch, it always cries click ; 



Then woe be to those in the house who are sick, 



For sure as a gun they will give up the ghost, 



If the maggot [beetle] cries click when it scratches the post." 



In many works we find the effects of other sounds upon 

 insects described, an instance of which has been especially 

 recorded in the great green grasshopper by Lehmann. 



As to the organs supposed to be the means whereby this 

 sense is enjoyed, W T C find that the opinions of the majority 

 of authors may be divided into those by which the seat of 

 this sense is asserted to be wholly unknown, and those who 

 consider that the antennae, in some way or other, perform 

 the functions of organs of hearing. Other opinions have, 

 indeed, been maintained by several other and distinguished 

 authors. Thus Treviranus described a small drum-like mem- 

 brane* on the forehead in front of the base of each antenna 



* Did not Treviranus here mistake the ocelli for ears ? 



D r 



