350 Miscellaneous. 



allows their base, which is not stuck, to obej^ the contractions of 

 the muscles of flight ; this base vibrates, and the buzzing is produced. 

 But all buzzing ceases if, by holding the wings pressed together over 

 as large an extent as possible, so as to exert a certain traction upon 

 their bases, all movement of those organs is rendered impossible. 

 However the wings be retained, provided their immobility be 

 complete, the buzzing absolutely ceases, contrary to Hunter's 

 opinion. 



2. By removing the scaly parts with which the margin of the 

 stigmata is furnished, far from doing away with the buzzing, as 

 asserted by Chabrier, it is not even modified, provided the operation 

 has not sensibly weakened the animal. 



3. The respiratory orifices may be more or less seriously injured 

 in different ways, we may introduce into them solid bodies of 

 considerable size, without preventing the buzzing or altering its 

 timhre. 



4. If the thoracic stigmata be stopped hermetically, as was 

 done by Burmeister, the buzzing is by no means annihilated ; it 

 is only weakened in proportion to the weakening of the flight 

 itself. 



There are then produced, especially in the Diptera, efi:ects which 

 merit notice. The animal becomes slow and lazy and no longer 

 flies willingly. If it flies, its flight, which is badly sustained, soon 

 stops ; then the insect sinks down and gives no more signs of life. 

 I once saw an Eristalis (E. teiiax) which, having escaped quickly 

 from my fingers towards the window after the occlusion of its 

 stigmata, fell ■without movement at my feet, completely exhausted 

 by a flight of a few centimetres. This result is not always produced 

 so rapidly ; but it never fails to supervene after a few efforts at 

 flight. It is easily explained by the complete absorption of the 

 provision of oxygen contained in the tracheae of the thorax, in con- 

 sequence of the contractions of the muscles of flight. It is a true 

 asphyxia. In a few minutes, however, the fly returns to life, owing 

 to the afllux of air through the abdomen into the thorax. The 

 animal can then again attempt to fly, or at least to walk : but actual 

 death is not long in coming. These effects are so constant and 

 easily obtained, that it is truly surprising that no experimenter has 

 called attention to them. 



The causes of the buzzing certainly reside in the wings. It has 

 long been recognized that the cutting of these organs more or less 

 near their insertion has a more or less marked influence upon the 

 buzzing. It becomes thinner and sharper ; the quality itself is 

 notably modified. It loses the softness (veloute) due to the friction 

 of the air upon the margins of the wings, and becomes in a manner 

 " nasal." The timhre perceived under these circumstances resem- 

 bles that of reed instruments, or still more that of certain electrical 

 contact-breakers, and has no resemblance to the sound that can be 

 produced by the passage of air through an orifice. This sound is, 



