Phlebotominae sand fly specimens were prepared for histological and physiological studies. Different fixatives were tested on sectioned and whole bodied adult females in order to obtain good fixation and provide satisfactory penetration of the embedding media. All fixed specimens were infiltrated (up There are few morphological studies on the internal organs of phlebotomine sand flies, vectors of the Leishmania spp. causing cutaneous and visceral leishmaniasis. Most published studies were done several years ago and involved predominantly Old World species (Adler & Theodor 1926, Christophers et al. 1926, Perfilev 1928a,b, Lewis & Minter 1960, Lewis 1965, Davis 1967. More recent publications on this subject refer to parasite-vector interactions or peritrophic membrane formation and blood digestion (Gemetchu 1974, Walters et al. 1987, 1989, 1995, Blackburn et al 1988. Guzman et al. (1994) and Abassy et al. (1995 a, b, c) using histological methods studied the physiology of feeding and embryonic development on Phlebotomus duboscqi and P. papatasi respectively under the light microscope obtaining satisfactory results what indicate these methods as practical tools for physiological studies of sand flies.The most recent literature on histological techniques suggests that historesin is a good alternative to paraffin for obtaining sections as thin as 0.5 µm, eliciting a better visualization of the tissue and cell structures (Junqueira 1995).Based on this and aiming to study the functional morphology of the salivary glands of adult phlebotomine sand flies, we developed a procedure in which specimens of Specimens of Lutzomyia longipalpis from a colony of the Laboratory of Leishmaniasis (CPqRR-Fiocruz) maintained in the laboratory according to the already preconized techniques (Brazil et al. 1997) were used. When pupation occurred the specimens were sexed as described by Brazil and Brazil (2000) and transferred individually to emergence vials. The vials were numbered and emergence of the insects monitored at hourly intervals. Unfed adult specimens were fixed at pre-determined times from the first hour after emergence until the fifth day. Five day-old sand flies were fed and fixed in the same way. Prior to fixation the insects were aspirated from the emergence containers, anaesthetized by cooling at 4°C and placed on a glass slide in a drop of fixative under a stereoscopic microscope. After removing the appendages each specimen was transferred to glass vials containing the fixative of choice.The following fixatives were evaluated for histology: Bouin's fluid, Carnoy's fluid, paraformaldeyde, Kleinberg's fluid and double fixation in Bouin's and Carnoy's fluids. Different fixation times were tested, ranging from 0.5-12 h. Specimens either had the scutellum removed, the thorax separated from the abdomen or where left entire.At the end of fixation, the specimens were rinsed several times in distilled water for 45 min until no more yellowish color could be seen. They were than transferred to 70% alcohol. When necessary the ins...