attached to ptilinum adult ptilinal muscle transverse-ptilinal muscle 18b 2022-07-05T13:30:44Z fly_anatomy.ontology A large temporary transverse muscle extending horizontally from one side of the ptilinum to the other, above the level of the antenna. It functions as a compressor of the ptilinal membrane after each distension pulsation and to permanently invaginate it after emergence. As with other temporary eclosion muscles, it soon degenerates and is not found in older flies. FBbt:00058809 transverse-ptilinal muscle temporary eclosion muscle