Preliminary electrophysiological tests on certain tarsal and ovipositor sensilla of stem-borers, Chilo partellus and Eldana saccharina, show that the sensilla are innervated by mechano- and contact chemoreceptor cells. Tarsal receptors are sensitive to sucrose, whereas the ovipositor sensilla are not and responses of the ovipositor mechanoreceptor units can be related to the oviposition behaviour of the moths.