HEARING IN INSECTS. 



93 



A, Father long-legs (Pedicia rwosa); a a, the poisers. B, The poisers, 

 a a, separate. C, the poisers, a a, and the winglets, b b. From De Geer. 



often repeated with the same result ; but when he 

 mutilated or removed either one or both winglets, the 

 buzzing ceased.* 



De Geer, upon examination of one of the wasp-flies 

 {Syrphidce)y satisfied himself that the buzzing was 

 produced by the friction of the root or base of the 

 wings against the sides of the hollow in which they 

 are inserted. For this purpose, he took hold of each 

 wing with his fingers and thumb, and stretching them 

 out in opposite directions, to prevent their motion, and 

 at the same time taking care not to hurt the insect, no 

 sound was produced. Not contented with this, he 

 cut off* both wings of a syrphus very near their roots ; 

 but this did not prevent it from buzzing any more than 

 the excision of jboth the poisers and the winglets, for, 

 on examining the parts with a microscope, he per- 

 ceived that the remaining roots of the wings continued 

 to vibrate, and the buzzing to go on, nor did it cease 

 till he completely eradicated the wings.| 



* Wiedemann, Archiv. , ii, 210 — 17. t Memoires, vi, 13. 



