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LETTER XXIV. 



ON THE NOISES PRODUCED BY INSECTS. 



That insects, though they fill the air with a variety of sounds, have no 

 voice, may seem to you a paradox, and you may be tempted to exclaim 

 with the Roman naturalist, What, amidst this incessant diurnal hum of 

 bees ; this evening boom of beetles ; this nocturnal buzz of gnats ; this 

 merry chirp of crickets and grasshoppers ; this deafening drum of Cicadas, 

 have insects no voice ! If by voice we understand sounds produced by 

 the air expelled from the lungs, which, passing through the larynx, is 

 modified by the tongue, and emitted from the mouth, — it is even so. For 

 no insect, like the larger animals, uses its mouth for utterance of any 

 kind : in this respect they are all perfectly mute : and though incessantly 

 noisy, are everlastingly silent. Of this fact the Stagyrite was not igno- 

 rant, since, denying them a voice, he attributes the sounds emitted by 

 insects to another cause. But if we feel disposed to give a larger extent 

 to this word ; if we are of opinion that all sounds, however produced, by 

 means of v/hich animals determine those of their own species to certain 

 actions, merit the name of voice ; then I will grant that insects have a 

 voice. But, decide this question as we will, we all know that by some 

 means or other, at certain seasons and on various occasions, these little 

 creatures make a great din in the world. I must therefore now bespeak 

 your attention to ihis department of their history. 



In discussing this subject, I shall consider the noises insects emit — 

 during their motions — when they are feeding, or otherwise employed — 

 when they are calling or commanding — or when they are under the 

 influence of the passions ; of fear, of anger, of sorrow, joy, or love. 



The only kind of locomotion during which these animals produce sounds 

 is flying: for though the hill-ants (^Formica rufa), as I formerly observed, 

 make a rustling noise with their feet when walking over dry leaves, I 

 know of no other insect the tread of which is accompanied by sound — 

 except indeed the flea, whose steps, a lady assures me, she always hears 

 when it paces over her night-cap, and that it clicks as if it was walking in 

 pattens ! That the flight of numbers of insects is attended by a hum- 

 ming or booming is known to almost every one ; but that the great 

 majority move through the air in silence, has not perhaps been so often 

 observed. Generally speaking, those that fly with the greatest force and 

 rapidity, and with wings seemingly motionless, make the most noise ; while 

 those that fly gently and leisurely, and visibly fan the air with their wings, 

 yield little or no sound. 



Amongst the beetle tribes (Coleoptera) , none is more noticed, or more 

 celebrated for " wheeling its droning flight," than the common dung-chafer 

 (Geotrupes stcrcorarius) and its affinities. Linne affirms — but the prog- 

 nostic sometimes fails — that when these insects fly in numbers, it indicates 



