 In addition to the Johnston's organ, antennae of Hymenoptera possess a second chordotonal organ, the Janet's organ, which detects flexion of the antennal joints, somewhat like the femoral chordotonal organ.The subgenual organ is found in all insects except Diptera and Coleoptera.It is located in the proximal part of the tibia and detects high-frequency acoustic vibrations transmitted through the substrate as well as sound through air.