A report on the species of the genera Velarifictorus, Modicogryllus and Mitius (Gryllidae, Gryllinae, Modicogryllini) from Thailand as conserved in the Zoological Museum Copenhagen, the Department of Agriculture Bangkok, and the authors collection is given. The collection comprised 16 species of Velarifictorus of which 15 are new to science (V. acutilobus, V. angustus, V. bicornis, V. bulbosus, V. confinius, V. gradifrons, V. horridus, V. minoculus, V modicoides, V. pui, V rectus, V. spinosus, V. sulcifrons, V. tenepalpus, V. triangularis) and one species, V. aspersus (Walker, 1869), is widespread in the Indo-Malayan region. Of the genus Modicogryllus, three species were found, M. consobrinus (Saussure, 1877), M. siamensis Chopard, 1961, and M. semiobscurus (Chopard, 1969). Previous authors often misidentified two of them making the following nomenclatorial corrections necessary: M. confirmatus Walker, 1859 is redescribed from the holotype; records from outside Sri Lanka should be verified. M. consobrinus (Saussure, 1877) is re-established as a valid species with the following synonyms: Gryllus lineiceps Walker, 1871 (= junior homonym of G. lineiceps Walker, 1869), Gryllus walkeri Chopard, 1961. A male from Teinzo (Burma) is fixed as lectotype. The following taxa become new synonyms of M. siamensis Chopard, 1961: M. confirmatus Bhowmik, 1977 (nec Walker, 1859), M. confirmatus Vasanth 1993 (nec Walker, 1859), M. pacificus Otte, 1994b. The genus Mitius is represented with two species, M. enatus Gorochov, 1994 and M. castaneus (Chopard, 1937). Information on stridulation of some Velarifictorus and Mitius species is given. The time pattern of stridulation of Mitius species is composed of diplo-pulses instead of single pulses as in other Gryllinae.