Revision of the genus Horstiella (Acari : Acaridae): Mites associated withneotropical Epicharis bees (Hymenoptera : Apidae)

The genus Horstiella is revised; one nominal species (H. armata Turk) and s ix new species, H. concentrica, H. megamyzidos, H. mourei, H. quadrata, H. snellingi, and H. variabilis, are described and illustrated. The species ar e associated with 14 species of Lees of the genus Epicharis from the Neotro pical region, ranging from central Mexico through Brazil. Mite species are not restricted to single Lee species, and two mite species may occur on the same host individual. The genera Horstia and Medeus are hypothesized to fo rm the sister group of Horstiella. Phylogenetic analysis produced a single cladogram resolved at the species level. H. mourei and the species pairs N, armat - quadrata, H. concentrica-megamyzidos, and H. snellingi-variabilis are each associated with species in one ol two subgenera of Epicharis. A ke y to the species of Horstiella is provided.