Three new Neotropical genera of Nasutitermitinae, of the group with mandibulate soldiers, are described. Cyrilliotermes, gen. n., is related to Curvitermes and includes C. cupim, sp. n. (type species), C. jaci, sp. n., C. cashassa, sp. n., C. strictinasus (Mathews, 1977), comb, n., and C. angulariceps (Mathews, 1977), comb, n., both C. strictinasus and C. angulariceps being removed from Curvitermes. Alates and soldiers are described for C. cupim, from Brazil, and for C. cachassa, from Suriname, and soldiers for C. jaci, from Suriname; a new locality is reported for C. strictinasus. Embiratermes, gen. n., is related to Armitermes and include E. festivellus (Silvestri, 1901), comb. n. (type species), E. benjamini (Snyder, 1926), comb, n., E. brevinasus (Emerson & Banks, 1957), comb, n., E. chagresi (Snyder, 1925), comb, n., E. heterotypus Silvestri, 1901), comb, n., E. latidens (Emerson & Banks, 1957), comb, n., E. neotenicus (Holmgren, 1906), comb, n., E. silvestrii (Emerson, 1949), comb, n., E. snyderi (Emerson & Banks, 1957), comb, n., E. spissus (Emerson & Banks, 1957), comb, n., and E. transandinus (Araujo, 1977), comb, n., all removed from Armitermes. The creation of Embiratermes, besides being based on morphological characteristics of soldiers, workers and alates, is justified by the defensive behaviour of the soldiers, which is different from that of Armitermes soldiers. Ibitermes, gen. n., which seems to be related to Embiratermes, includes only I. curupira, sp. n., described from a series of soldiers and workers from Brazil. Keys based on the soldier caste are provided for the identification of the 11 genera with mandibulate soldiers of the Nasutitermitinae, and for the species of Rhynchotermes, Curvitermes and Cyrilliotermes. Curvitermes planioculus Mathews, 1977 is considered a junior synonym of C. minor (Silvestri, 1901), syn.n.