Tegminal amplifiers and spectrum consistencies in Conocephalus nigropleurum (Bruner), Tettigoniidae

The sound frequency spectrum of Conocephalus nígropleurum (Bruner) was investigated with two different models of a custom-built analyser. The spectrum is continuous from 0 to 100 kc/s and contains a band of markedly more intense frequencies extending from 28 to 60 kc/s. When sufficient care was taken to eliminate variation due to microphone-insect alignment, this band or intensity aggregate was found to be highly consistent in the amplitude of its component frequencies.The proximal portions of the tegmina contain modified cells. Tearing these cells produced a large reduction in intensity over the entire spectrum but failed to alter the location and shape of the aggregate. It is concluded that the tegminal wing cells function exclusively as amplifiers. The vein network is suggested as a structural source of the aggregate. A cantilever model is used to represent probable vein oscillation.