The species of the genus Spathiostenus Belokobylskij, 1992 are revised and illustrated. A redescription of the type species Eucorystes formosanus Watanabe, 1934 is given. Two new species are described: S. brevicauda sp. nov. from New Guinea and S. pasohus sp. nov. from Malaysia and Brunei. A new synonym (Eucorystes formosanus Watanabe, 1934 = Eucorystes tenuis Nixon, 1943, syn. nov.) and a new combination [Polystenus anacolus (Chen & Shi, 2004), comb. n.] are suggested. The transformation of the first tergite into the petiole in Doryctinae and the status of the genus Spathiostenus are discussed.