Guamampa n.g. is a genus of Aegistinae (Bradybaenidae) characterized by the presence of a single mucus gland entering the stylophore; the distal portion of vas deferens much enlarged; a flagellum of peculiar appearance; the penial verge grooved; and the vagina enlarged and coated with dense white cover. The type species is Helix tuba Albers, 1854 from Sulawesi, Indonesia. Certain characters of Guamampa and of Tricheulota, from the Philippines, are shared by the American genus Monadenia. Monadeniinae is elevated to family rank within the Xanthonychoidea.