In the present article, the Gryllacrididae and Tettigoniidae fauna of Espiritu Santo Island (Vanuatu) is examined. We took advantage of the examination of the material collected during the SANTO 2006 biological survey to give description complements, or to redescribe and/or redefine the concerned species and genera. We recorded 15 species in the island. Five are recorded for the first time in Espiritu Santo and in the Vanuatu archipelago. A 16th species, Conocephalus laetus (Redtenbacher, 1891), recorded by Willemse (1925) has not been collected during the survey. Two new Gryllacrididae Amphibologryllacris butmasi n. sp. and Psilogryllacris tchancha n. sp. are described. Amphibologryllacris macrocera (Walker, 1869) is redescribed. Amphibologryllacris poultoni (Willemse, 1925) is synonymised under A. macrocera. The two related genera Amphibologryllacris and Nannogryllacris are redefined. All Xanthogryllacris punctipennis (Walker, 1869) subspecies recognized by Karny are re-established as subspecies under this genus: X. p. punctipennis (Walker, 1869); X. p. confluens (Griffini, 1909); X. p. erimae (Griffini, 1909); X. p. fenestrigera (Griffini, 1913); X. p. gemmicula (Hebard, 1922); X. p. keyica Karny, 1925 (n. comb.); X. p. zatricia Karny, 1928. Epacra cyaneoterminata Karny, 1935 is transferred to Amphibologryllacris. The song and stridulatory file of most Tettigoniidae occurring in Espiritu Santo are described, most of them for the first time: Salomona redtenbacheri Brongniart, 1897; Phaneroptera gracilis Burmeister, 1838; Furnia insularis (Stål, 1876); Ityocephala francoisi Bolívar, 1909; Conocephalus upoluensis (Karny, 1907); C. semivittatus (Walker, 1869); Pseudorhynchus lessonii Serville, 1838; Phisis holdhausi Karny, 1926. The female of Ityocephala francoisi, a Mecopodinae possibly endemic to Espiritu Santo is described for the first time. Salomona redtenbacheri is redescribed and synonymised with S. magnifica Willemse, 1925 and S. haani Brongniart, 1897. Keys to species of Amphibologryllacris, Nannogryllacris, and Furnia are given and characters are illustrated. Keys to Tettigoniidae and Gryllacrididae of Espiritu Santo are given and illustrated.
Insecta, Orthoptera, Gryllacrididae, Tettigoniidae, acoustic communication, Southwestern Pacific, Vanuatu, new species.