A new subgenus of the bee genus Megachile (Megachilinae: Megachilini) is described from Mt. Matang in Borneo. Matangapis, new subgenus, is proposed for Megachile alticola Cameron, and is most noteworthy for the possession of arolia on all pretarsi of both sexes. The significance of arolia on M. alticola is briefly discussed in the context of the distinctiveness of the tribes Megachilini and Osmiini. Notes on two Oriental subgenera of Megachile, Orientocressoniella and Neocressoniella, are appended. The following taxonomic changes are proposed: Orientocressoniella is a new junior synonym of Callomegachile, Neocressoniella is a new junior synonym of Xanthosarus, Anthophora barbata Fabricius is a new synonym (senior but suppressed) of M. carbonaria Smith, M. amputatiformis Cockerell is a new junior synonym of M. saigonensis Cockerell, M. saphira Cockerell is a new junior synonym of M. ulrica Nurse. In addition, the following five species are newly transferred to subgenus Chelostomoda: M. ulrica, M. lefroma Cameron, M. albolineata Cameron, M. funnelli Cockerell, and M. bougainvillei Cockerell. Lectotypes are newly designated for M. alticola and M. anthracina Smith.