444 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



bee gives a tone more than an octave higher. This depends 

 on the number of wing-vibrations in a given time. Marey 

 lias counted the number of vibrations of the insect wing, by 

 help of a graphic method. Landois has prepared a table of 

 musical notes and their corresponding vibrations, so that it 

 becomes easy to determine the number of vibrations of the 

 insect's wing, provided that the flight-tone be distinguished 

 from the voice. lie states that the female of a bumblebee 

 (Bombus miiscorum) hums in flight the note a, which is 

 equivalent to 220 strokes of the wing per second. The honey- 

 bee sounds with its wing-motion the note ', and therefore 

 makes 440 per second, which is just double the number of 

 vibrations made by the bumblebee. 



Fresh observations on the buzzing of insects have been 

 made by J. Perez. He believes that the cause of buzzing 

 certainly resides in the wings. In the Hymenoptera and 

 Diptera the buzzing is due to two distinct causes one, the 

 vibration of which the articulation of the wing is the seat, 

 and which constitutes true buzzing; the other, the friction 

 of the wing, an effect which more or less modifies the former. 

 In moths of strong flight, such as the sphinges, the soft and 

 full buzzing which these animals produce is only due to the 

 friction of the air by the wings. This sound, which is always 

 grave, is alone produced. It is not accompanied by the basal 

 beatings, owing to a peculiar organization, and especially to 

 the presence of the scales. In the dragon-flies also, in which 

 the base of the wing is furnished with soft fleshy parts, no 

 true buzzing occurs ; but a simple rustling, due to the fric- 

 tion of the organs of flight. M. Perez believes that the pas- 

 sage of air through the respiratory orifices has nothing to do 

 with the production of sound, as when injured or closed the 

 buzzing goes on. When the stigmata, or air-holes, are stop- 

 ped hermetically, as was done by Burmeister, the buzzing is 

 only weakened, as the insect itself is partially asphyxiated 

 by the loss of fresh air. When as Chabrier did Perez stuck 

 together the wings of a fly, the sound was still produced, as 

 the base of the wing continued to vibrate, and the buzz^ 

 ing sound to be produced. But all buzzing was stopped if, 

 by holding the wings pressed together, over as large an ex- 

 tent as possible, so as to exert a certain traction upon their 

 bases, all movements of these organs are rendered impossible. 



