Two species of the genus Latibulus are recognized from Japan including a new species, L. hokkaidensis n. sp. from Polistes reparius Sk. Yamane et S. Yamane and Polistes snelleni (Saussure) (Hymenoptera: Vespidae). They are decribed for the seasonal variation (spring and summer forms). A key to species for the Japanese Latibulus is provided with photographs.