The genera Erhaia and Tricula (Gastropoda, Rissooidea, Amnicolidae and Pomatiopsidae) in Bhutan and elsewhere in the eastern Himalaya

Shells of the Rissooidea species that are known from Bhutan are characterized. Tricula montana is reported from that country for the first time. Two Erhaia species from Bhutan are described as new to science, viz. E. janneisp. nov., and E. pelkiaesp. nov., The holotypes of the Erhaia species that were described from Nepal are figured with photographs for the first time and compared with the congeneric taxa from Bhutan and India. Erhaia nainitalensis is considered a senior synonym of E. chandeshwariensis. An identification key is presented for the Erhaia species of the Himalayan foothills.