Holotypes and syntypes of cecidomyiid genera and species described from the Seychelles and East Africa by J.-J. Kieffer in the early 20^th century are held in the collections of the Natural History Museum, London and the Muséum national d'Histoire naturelle, Paris, France. All are specimens caught in flight, so without associated biological data and most are unidentifiable females. Many are in poor condition and inadequate for detailed study and are of little assistance in advancing understanding of the Afrotropical Cecidomyiidae fauna. Following examination of all extant specimens, 16 genera and 59 species are listed and assigned to nomina dubia. Six other species that are represented by holotypes or syntypes that still have intact genitalia (which may possibly be recognised in future revisionary studies), are also listed.