Light microscopy of native preparations, histology, and electron microscopy have revealed that Phlebotomus duboscqi belongs to a class of sand fly species with prompt development of the peritrophic matrix. These results suggest that L. major chitinase does not have an important role in parasite escape from the PM.
Promastigotes remain in the intraperitrophic space until the PM is broken down by sand-fly-derived chitinases and only then migrate anteriorly. Disintegration of the PM occurs simultaneously with the morphological transformation of parasites from procyclic forms to long nectomonads.