The mouthparts and antennae of the fourth-instar larvae of four sand fly species were studied using scanning electron microscopy. The morphology of the clypeus, labrum, mandible, maxilla, mentum, and antennae were compared forPhlebotomus argentipesAnnandale & Brunetti,P. papatasin(Scopoli),Sergentomyia babu babu(Annandale), andS. bailyi(Sinton). Most of structures exhibited species-specific features, particularly the characteristics of the antennae.P. papatasinlarvae had heart-shaped antennae, a long mandible, stout maxilla, and a heavy mentum with large teeth. In contrast,P. argentipeslarvae had dumbbell-shaped antennae and a singular club-shaped labrum. The antennae ofS. b. babuwere ovoid, whereas those ofS. bailyiwere elliptical. The labrum ofS. b. babuwas lanceolate, whereas that ofS. bailyiwas rounded and exhibited a small, thick projection with several folds. The teeth of the mentum of bothSergentomyiaspecies were shorter than those of thePhlebotomusspecies. Species-specific differences in the morphology of larval mouthparts and antennae indicate that it may not always be necessary to rely on adult morphology to identify sympatric phlebotomines.