part of develops from adult maxillary segment rostrum maxillary palp fly_anatomy.ontology FBbt:00004546 The paired sensory appendage of the adult maxillary segment, located laterally on the proboscis. It is covered with stout hairs, and on the dorsal side with basiconic sensilla similar to those of antennal segment 3. There are four long slender bristles locate distally and about 16 small bristles in a longitudinal band on the posterior surface. maxillary palpus palpus appendage presumptive maxillary palp