The development of four isolates of Leishmania from foci of
American cutaneous leishmaniasis was studied in Lutzomyia
longipalpis. The suggestion that the differences in the
development of the Leishmania in the invertebrate host are of
great taxonomic significance was confirmed. The pattern of
development of three strains was typical of parasites of the
subgenus Leishmania, the other was similar to Leislunania of the
subgenus Viannia. The identification of the strains using other
criteria is in agreement with biological characterization. The
results show that the morphological and morphometric study
ofpromastigotes do not clearly define the taxonomic position of
the parasites but other studies are needed to confirm this.