The subgenual organ is an organ in insects that is involved in the perception of sound. The name (Latin sub: "below" and genus: "knee") refers to the location of the organ just below the knee in the tibia of all legs in most insects. The function of the organ is performed by aggregations of scolopidia, the unit mechanoreceptor in invertebrates. The organ is thought to be an evolutionary artifact of ancestral insects who used their legs to detect vibrations in the underlying substrate.