382 NOISES dF I\SECT5. 



that the remaining fragments of the wings were in con- 

 stant motion all the time that the buzzing continued ; 

 but that upon pulling them up by the roots all sound 

 ceased^. Shelver's experiments, noticed in my la^^t 

 letter, go to prove, with respect to the insects that he 

 examined, that the winglets are more particularly con- 

 cerned with the buzzing. Upon cutting off the wings 

 of a fly — but he does not state that he pulled them up 

 by the roots — he found the sound continued. He next 

 cut off the poisers — the buzzing went on. This expe- 

 riment was repeated eighteen times with the same re- 

 sult. Lastly, when he took off the winglets, either 

 wholly or partially, the buzzing ceased. This how- 

 ever, if correct, can only be a cause of this noise in the 

 insects that have winglets. Numbers have them not. 

 He next, therefore, cut off the poisers of a crane-fly 

 {Tipula crocatdy L.), and found that it buzzed when it 

 moved the wing'. He cut off half the latter, yet still 

 the sound continued; but when he had cutoff the whole 

 of these organs the sound entirely ceased ''. 



Aristophanes in his Clouds, deriding Socrates, intro- 

 duces Chaerephon as asking that philosopher whether 

 gnats made their buz with their mouth or their tail". 

 Upon which Mouffet very gravely observes, that the 

 sound of one of these insects approaching is much more 

 acute than that of one retiring ; from whence he very 

 sapiently concludes, that not the tail but the mouth 

 must be their organ of sound ''. But after all, the fric- 

 tion of the base of the wings against the thorax seems 

 to be the sole cause of the alarming buz of the gnat 



' Dc Geer, vi. 13. " Wiedemann's ArcMv. Vi. 210. S17. 



"■ Act i. Sc. 'i. * Mouffet, 81. 



