Nomenclatural changes are made in three previously described genera in the planthopper tribe Hemisphaeriini (Hemiptera: Fulgoromorpha: Issidae: Issinae), viz Gergithus Stål, 1870, Mongoliana Distant, 1909 and Hemisphaeroides Melichar, 1903. In addition, a new genus, Gnezdilovius gen. nov., with Gergithus lineatus Kato, 1933 as its type species, is described for 40 species formerly included in Gergithus, and the generic characteristics of the latter genus is revised. One new species, Gergithus frontilongus sp. nov. from China (Yunnan), is described and illustrated. One additional Gergithus species, previously misidentified as G. signatifrons Melichar, 1906 from Siberut Island, is mentioned and illustrated. Gergithus contusus Walker, 1851 is transferred to Mongoliana and Hemisphaerius atromaculatus Distant, 1916 and H. fuscoclypeatus Distant, 1916 are transferred to Hemisphaeroides. Checklists for all four genera are provided detailing the nomenclatural changes and a key to the 19 genera of Hemisphaeriini is provided. Morphological diversity and distribution of the genera are briefly discussed.