A new genus and species of bostrichid beetle, Octomeristes gen. nov. and Octomeristes pusillus gen. et sp. nov., in the tribe Xyloperthini is described from litchi (Litchi chinensis Sonn.) wood in Thailand. The genus is compared to Octodesmus Lesne, 1901, the only other xyloperthine genus with eight-segmented antennae, and to the xyloperthine genera, Xylion Lesne, 1901, Xylionulus Lesne, 1901 and Xylobosca Lesne, 1901. A new combination, Octomeristes minutissimus (Lesne, 1932) comb. nov., is transferred from Octodesmus Lesne, 1901. A lectotype is designated for Octodesmus episternalis Lesne, 1901, the type species of Octodesmus. Octodesmus kamoli Chûjô, 1964 is designated a new synonym of Paraxylion bifer (Lesne, 1932). A key is provided to the species of Octodesmus and Octomeristes gen. nov.
Octomeristes gen. nov., Octodesmus, Paraxylion, lectotype, new synonymy.