part of develops from haltere disc adult metathoracic segment adult external thorax haltere https://www.ento.csiro.au/biology/drosophila/melanogaster.html?halter fly_anatomy.ontology UBERON:0000987 FBbt:00004783 Paired dorsal 'appendage' of the adult mesothoracic segment. It is a freely movable, capitate stalk. It develops from the dorsal mesothoracic disc. It is used for flight balance. appendage ventral ectoderm derivative