develops from embryonic/larval tracheal section embryonic/larval tracheal dorsal trunk larval DT fly_anatomy.ontology The main airway of the larval/embryonic tracheal system, linking its metameric units and spanning the length of the animal from the anterior spiracle in the prothoracic segment to the posterior spiracle in A8 on the same side. There are two per larva, left and right. larval dorsal longitudinal trunk larval dorsal trunk FBbt:00000212 larval great lateral trunk FBbt:00005577 primary tracheal branch tracheal dorsal trunk primordium