Gergithoides Schumacher, 1915 in Vietnam, with two new species, and taxonomic notes on the genus (Hemiptera: Fulgoromorpha: Issidae)

Two new species of the genus Gergithoides Schumacher, 1915 (Issinae, Hemisphaeriini), G. gnezdilovi sp. nov. from Bidoup-Nui Ba National Park in Central Vietnam and G. nui sp. nov. from Pia-Oac National Park in North Vietnam, are described. These are the only species of the genus formally recorded from Vietnam to date. Habitus, details and male genitalia are illustrated and a distribution map is provided. Four females representing three or four additional species, known from females only, are mentioned and illustrated. Taxonomic and biogeographical updates based on a thorough review of the literature are proposed and discussed for G. carinatifrons Schumacher, 1915, G. rugulosus (Melichar, 1906) and G. undulatus Wang & Che, 2003.