part of overlaps develops from larval tracheal system embryonic/larval tracheal system fly_anatomy.ontology FBbt:00000185 Tracheal system of the late embryo or larva. The three larval instars retain the same basic pattern of the tracheal system, but with increasing complexity of branch trachea. It is composed of ten tracheal metameres. FBbt:00005570 larva tracheal system presumptive embryonic/larval tracheal system