Notes on Papuasian and Malesian stingless bees, with the descriptions of new taxa (Hymenoptera: Apidae)

Two new species of the stingless bee genus Heterotrigona Schwarz (Apinae: Meliponini) are described and figured from Papua New Guinea: Heterotrigona (Sahulotrigona) tricholoma Engel, new species, lighter individuals of which superficially resemble the larger H. (Platytrigona) lamingtonia (Cockerell) and H. (P.) keyensis (Friese), and H. (S.) taraxis Engel, new species, a taxon generally misidentified as “Trigona atricornis Smith”.  The western Malesian (Borneo) species H. hobbyi (Schwarz) is removed to Borneotrigona Engel, new subgenus, and distinguished from the otherwise eastern Platytrigona Moure, which occur in eastern Wallacea (east of Weber’s line) and Papuasia.  The historically misidentified T. atricornis is a senior synonym of T. genalis Friese (new synonymy), the latter type species for the genus Papuatrigona Michener & Sakagami, resulting in the following nomenclatural change: Papuatrigona atricornis (Smith), new combination.  Flavotetragonula Shanas is placed as a new synonym of Tetragonula Moure s.str. (new synonymy)