part of abdominal sternite 2 Wheeler's organ FBbt:00004807 Aco VFB:FBbt_00004807 abdominal chordotonal organ FBbt:00004809 fly_anatomy.ontology A chordotonal organ associated with the anterior of abdominal sternite 2. It is visible externally as a raised patch of smooth cuticle without trichomes or bristles. It consists of two clusters of scolopidia (FBbt:00005217), one on either side of the ventral midline (Smith and Shepherd, 1996). The sensory neurons of Wheeler's organ project through the second segmental nerve of the abdomen and then through the abdominal neuromeres via dorso-lateral tract of the ventral fasciculus (DLV), to terminate in the prothoracic neuromere (Smith and Shepherd, 1996). adult chordotonal organ