AbstractMites of the genus Listropsoralges permanently parasitizing New World marsupials of the family Didelphidae are revised. An emended diagnosis of this genus, descriptions of the new species L. caluromys sp. nov. and L. faini, and a key to species based on males are provided. Listropsoralges caluromys differs from the morphologically similar L. marmosae by shorter setae se (35–37 μm long in males and 48–55 μm long in females), by female setae h3 not being thickened and being subequal in the length to setae ps2 and ps3 (12–14 and 9–10 μm long, respectively) and by pretarsi III represented by only remnants of the pretarsal stalk in both sexes. L. faini sp. nov. (only males are known) differs from males of the morphologically similar L. monodelphis by having homogeneous ornamentation of the hysteronotal shield and by setae h2 and h3 not being positioned on distinct fleshy projections.