Two darkling beetles from the subfamily Lagriinae from the late Pliocene of Japan, Kabutoiwa Member (early Piacenzian, ∼3.5 Ma) of the Motojuku Formation are discussed: Lagria koshimizui sp. nov. and Lagria aff. formosensis Borchmann, 1912. These are the first members of the family Tenebrionidae recorded from Pliocene and the first clearly documented fossil species of the genus Lagria. The new species differs from all extant East Asian congeners in the elliptical and short female antennomere 11, which is less than two times as long as previous one. The second species appears very similar to Lagria formosensis Borchmann, 1912, but we cannot assign it to this species with certainty. The absence of Lagria koshimizui sp. nov. and L. aff. formosensis in the contemporary fauna of the main Japanese islands may point on the possible thermophily of both these species and their subsequent extinction.