Two New Tropical Aesalus (Coleoptera, Lucanidae) from the Malay Peninsula

Two new species of the genus Aesalus are described from the Malay Peninsula. One of them, named A. matsuii, is collected from a high altitude of 1, 300m, while the other, named A. yongi, from a low altitude of about 100m. These two species are distinct from the other Southeast Asian Aesalus species by having a pair of deep cavities on the metasternum and no clumps of erect scale-like bristles on the dorsal surface, and can be clearly distinguished from each other by the difference in configuration of male genitalia. A key to the Southeast Asian species of the genus Aesalus is also provided.