Grandjeanicus gabonensis Coineau and Theron n. sp. shows a functional grouping of two setae and a trichobothrium at the extremity of its first pair of legs, which is interpreted as novel system of acoustic communication. A hair termed C, which has its base solidly implanted on the tibia, is prolonged by a long, densely-ciliated flagellum, suspended on a spring-like structure. A small posterior projection (lp) establishes contact with the trichobothrium (T) implanted on the tarsus which slides in the middle of the supporting spring of the flagellum. Through its large surface of contact, the-latter can resonate in response to a relatively weak stimulus and transmit its vibrations to the trichobothrium. The last segment of leg I also shows a solidly-implanted hypertrophied hair (A), the upper ridge of which bears a row of teeth, Flexion of the tarso-apotele, relative to the tibia, places a spine (e) of hair C in contact with the row of teeth on hair A, thus causing microstridulation. The system caused to vibrate in this way can in turn stimulate the equivalent system borne by a conspecific.