A new genus and two new species of Pygmephoridae (Acari: Heterostigmata) phoretic on Lasioglossum (Hymenoptera: Halictidae) in Japan.

A new genus and two new species of pygmephorid mites belonging to the subfamily Neopygmephorinae are described from Japan under the names Insensilla lasioglossi and I. duplicis. They are known only from the adult females found attached to the halictid bees, Lasioglossum apristum (Vachal) and L. duplex (Dalla Torre), respectively. The new genus is readily distinguished from all the known genera of the family by that the prodorsum entirely lacks the so-called sensillum (=seta sc1), but that the bothridium is retained though fairly reduced in size. I. lasioglossi, the type species, is easily discriminated from I. duplicis, the other member of the genus, by possession of much stronger barbs on the apices of most dorsal idiosomal setae, obviously shorter coxal setae, and so forth.