The Brentidae is characterized by the reduced labial palpi, which is located in cavities on the apicoental margin of the prementum. The postcoila of two subfamilies of this family is deep and bowl-like on ental surface of the hypostomal arms. The mouthparts treated in here comprise the labrum, clypeus, mandibles, maxillae, labium, hypostoma and the septum of the preoral cavity. The terms are followed principally after Ting and Morimoto. The detail terminology fur the mandibles are newly given. [Insecta, Coleoptera, Comparative morphology, Mouthparts, Brentidae].