Figure 1.

Developmental forms of Leishmania promastigotes showing from left to right an amastigote ingested from an infective bloodmeal; a procyclic promastigote, a short, ovoid, slightly motile, first promastigote that appears in the sandfly; a nectomonad promastigote, a long slender form; a haptomonad promastigote, a shorter and broader form; a paramastigote promastigote, a rare form with the kinetoplast adjacent to the nucleus; and a metacyclic promastigote, a short, slender, highly active, infective form for the vertebrate host.