The Physiology of the Tettigoniid Ear

Abstract

The threshold curve obtained for the whole organ, with a lateral sound source 30 cm from the insect, indicates the degree of interaction that occurs between the spiracular and tympanal slits inputs. The threshold curve for the whole organ with the spiracle blocked shows an increase in threshold to the level of the tympanal slits, and suggests that diffraction phenomena may be important during sound reception. Measurement of the sound intensity emitted by mechanical vibration of the tegmen shows that there is a fall in sound intensity from 124 dB at source to 54 dB at the spiracle; the spiracular intensity is still above the spiracular threshold, however.