Atheta (Microdota) usingeri, Bernhauer, 1942

Bernhauer, Max, 1942, Coleoptera, Staphylinidae Of Guam, Insects of Guam I, Bernice P. Bishop Museum, pp. 41-44 : 44

9. Atheta (Microdota) usingeri , new species.

Reddish to blackish brown, the base and hind margin of the elytra light yellow, base and apex of abdomen reddish yellow, antennae rust brown with paler scape, palpi and legs dirty yellow. Head shiny, much narrower than prothorax, transverse, puncturation sparse, extremely fine, and scarcely visible. Eyes fairly large, temples behind them shorter than lengthwise section of eyes viewed from above; underside finely edged. Antennae much longer than head and prothorax together, but still short, thickened toward the apex, the third segment much shorter than the second, the fourth about as long as wide, the following segments gradually becoming shorter and wider, the penultimate fairly strongly transverse, in the shortest view about one half again as wide as long, apical segment large, longer than the two preceding together. Prothora:r convex, as wide as elytra at the shoulders, about half wider than long, widest posteriorly, with blunt hind angles, strongly narrowed anteriorly, feebly rounded, without impression in front of the scutellum, extremely finely and sparsely punctured, shiny, clothed with fine grayish yellow hair like upper surface of body. Epipleurae fairly strongly recurved, visible posteriorly when viewed from the side. Elytra hardly longer than prothorax, together much wider than long, inner side of outer posterior angles distinctly margined; moderately finely punctured, much stronger and denser than on the prothorax, distinctly rough, laterally as well as on thorax with dark uneven cilia. Prothorax is somewhat narrowed posteriorly, at the base the first free lying tergites transversely furrowed, finely and sparsely punctured, finer and sparser posteriorly, shiny, on the sides with numerous black cilia. Length, 1.5-1.9 mm.

Barrigada, June 12, ex leaf mold, Usinger.

Distinguished by the coloration and the moderately strongly convex ciliated prothorax. With the acquisition of greater material, it may be placed in a new subgenus.