Insects' Wings (Rate At Which They Move. The buzzing and humming noises produced by winged insects are not as you suppose vocal sound. They result from sonorous undulations imparted to the air by the dapping of their wings. This may be rendered evident by observing that the noise always ceases when the insect alights on any object. The sirene has been ingeniously applied for the purpose of ascertaining the rate at which the wings of inch creatures flap. The instrument being brought into unison with the sound produced by the insect, indicates, as in the case of any other musical sound, the rate of vibration. In this way it has been ascertained that the wings of a gnat flap at the rate of 15,000 times per second. The pitch of the note produced by this insect in the act of flying is, therefore, more than two octaves above the highest note of a seven-octave pianoforte.