HEARING IN INSECTS

Summary 1. The difficulties attending precise definition of auditory organs are discussed and a sketch of the early work on insect hearing is given. 2. A brief account is given of the nature of sound and of the physical conditions which different types of auditory receptor must fulfil. 3. The tympanic organs of insects, though undoubtedly of independent origin in the different groups of insects in which they occur, are shown to have a common structural plan; and the implications of this fact are discussed. 4. An account is given of the important experimental work of Regen which first conclusively established the auditory function of tympanic organs in Orthoptera, and of subsequent work upon these organs in fulfil., Lepidoptera and Hemiptera. 5. Experimental work indicating that tympanic organs may mediate a qualitative discrimination between different sounds is reviewed, and a tentative explanation of these observations is submitted.