The uncommonly encountered bee tribe Tarsaliini (Apinae) is recorded from the Arabian Peninsula for the first time, and based on a new species of the genus Tarsalia Morawitz. The tribes Ancylaini and Tarsaliini are diagnosed and their differences highlighted. Tarsalia kindahensis Engel, new species, is described and figured from the eastern portion of the Najd of central-eastern Saudi Arabia (Qassim and Riyadh regions). The new species is most similar to T. mimetes (Cockerell), known only from Egypt and Sudan, as well as the larger T. persica (Warncke) from Iran. These three species are morphologically and largely geographically distinct from the remainder of the genus, and are segregated into a new subgenus, Astibomelissa Engel. An updated and corrected checklist of the genera and subgenera of bees recorded from Saudi Arabia is appended.