Small to medium sized, brown; Antennae of male reaching beyond apices of elytra (so this one probably a female); Eyes moderately coarsely faceted, deeply emarginate; Antennal tubercles broadly separated, distant from mandibular articulation; Antennal scape distinctly shorter than pronotum, pedicel variable, antennomere 3 subequal to scape, antennomeres 3-7 no apical spines; Pronotum no dorsal tubercles, lateral margins rounded; Elytra without costae, without ivory coloured markings, punctates clearly visible, not in regular rows, apices rounded; Femora strongly clavate (like a club, thicker at apex than the base); tibia not flattened.
Previous comment is a description for Bethelium in general. For B. diversicorne see: https://sites.google.com/site/insectsoftaschrysomeloidea/suborder-polyphaga/cerambycidae-longicorn-beetles/genus-bethelium/bethelium-diversicorne