continuous with adult tracheal section adult tracheal lateral trunk fly_anatomy.ontology Longitudinal tracheal branch of the adult, ventral to the dorsal trunk. It joins the dorsal trunk immediately behind the first thoracic spiracle. In the thorax it is extended into a series of air sacs (propleural, sternopleural and hypopleural). In the abdomen, at the level of the third pair of spiracles it becomes more tracheate and extends through to the seventh spiracle. It is connected to the lateral trunk in each abdominal segment by a long transverse connective. At the level of the second pair of spiracles, these connectives are much shorter and stouter. FBbt:00003040 adult tracheal transverse connective adult abdominal spiracular tracheal branch tracheal branch