part of attached to adult abdominal segment lever of abdominal spiracle adult abdominal spiracle adult somatic muscle of abdomen spiracular occlusor muscle occlusor muscle of adult abdominal spiracle 2022-07-05T13:30:44Z fly_anatomy.ontology A short muscle that functions in closing an adult abdominal spiracle. These muscles are attached to sclerotised lever which is in turn attached to a deep fold in the wall of spiracle at the base of the spiracular chamber. The other end is attached to a rigid part of the wall of the spiracular chamber so that its contraction closes the passage. There is no dilator muscle so the passage is probably kept open by its natural elasticity (Miller, 1950 pg 459). FBbt:00059065