The presence of metacyclical promastigotes of Leishmania pifanoi in the hypopharyngeal duct of Lutzomyia youngi is reported. The insects were experimentally infected by engorgement on the tarsal lesions of hamsters. The metacyclics, whose morphology is illustrated, appeared in the hypopharynx 5 to 9 days after engorgement; they were more frequently found in the insects fed on unrefined commercial sugar. They role of amino derivates of glucose and galactose, as well as of amino acids in the development and migration of metacyclics, is investigated.
Psychodidae; Leishmania mexicana; Sucrose
