The above species, of which Mr. René Oberthür kindly sent me the type-specimen (a ♂ from Siam) for examination , undoubtedly belongs to the genus Melanauster, and is very closely allied to Melanauster Medenbachii Rits. which latter, according to a male specimen in the Leyden Museum , inhabits the Island of Java. Thomson’s species, however, has the 3rd and 4th joints of the antennae distinctly less (almost imperceptibly) swollen at the tip, so as to make these joints more regularly cylindrical, the scutellum is shorter, and broader at the base, the shoulders are more broadly rounded, and the front-tibiae are more slender. It has moreover a glabrous band along the middle of the pronotum, the glabrous transverse bands of the elytra are as broad as those formed by the small golden green scales (in Medenbachii they are distinctly narrower), and, last not least, the erect black stiff hairs on the elytra are decidedly longer in zonalor than in Medenbachii. The grey colour of the scaly pubescence in my specimens of Medenbachii, most probably will prove to be due to their having been preserved for some time in spirits.