Six new Metarbelidae are described. Photographs of the adults, illustrations of their wing venation and genitalia, as well as information on the floristic composition of their habitats, are presented. Five species are from Tanzania, which include Metarbela lornadepewae spec. nov. from Mufindi (Udzungwa Mountains), Ortharbela jurateae spec. nov., Lebedodes ianrobertsoni spec. nov. and Lebedodes leifaarviki spec. nov. from Morogoro (Uluguru Mountains) and Ortharbela cliftoni spec. nov. from Amani (East Usambara Mountains). Paralebedella shimonii spec. nov. from Marenji Forest (Kenyan Coast) is the first described species of the genus Paralebedella for Kenya, and considered to be very rare. At least five genera and ten species occur in Morogoro and its surroundings which is a very high diversity of Metarbelidae. A characteristic feature of the Morogoro sites is the occurrence of at least four Lebedodes species. This is 16% of Lebedodes known from the Afrotropical Region (including undescribed species) and the highest diversity for a single locality. It appears to be due to the presence of miombo characterized by the dominance of leguminous trees of the genera Brachystegia, Julbernardia and/or Isoberlinia. The distribution pattern of the Metarbelidae from the Afrotropical Region, Madagascar and via the Arabian Peninsula into the Oriental Region is presented. There appears to be evidence for ancient (probably Cretaceous), relictual taxa.