Key to species of Acrolocha of the eastern Palaearctic Region

1 Head between eyes flattened. Elytra without strong microsculpture, with coarse punctures arranged in longitudinal rows. Metatrochanters with posterior angulated projection (see WATANABE 2007: Figs 2, 7). Male abdominal sternite VIII with thin median projections. ............................................................................................................................... 2

– Head between eyes distinctly convex. Elytra with strong microsculpture, with or without punctures. Metatrochanters lacking projection. Male abdominal sternite VIII lacking median projections. ........................................................................................................ 3

2 Pronotum distinctly convex, widest in middle part. Elytra dark brown, less than twice as long as pronotum. Inner side of male metafemur with distinct triangular tooth in median portion (WATANABE 2007: Fig. 2). Apical margin of male abdominal sternite VIII with three median projections (see WATANABE 2007: Fig. 3). Median lobe of aedeagus wide, parameres narrow (see WATANABE 2007: Figs 4−6). Body length: 2.20−2.40 mm. Japan. ......................................................................................... A. horiguchii Watanabe, 2007

– Pronotum flattened, widest in anterior third. Elytra yellowish-brown, more than twice as long as pronotum. Inner side of male metafemur without triangular tooth in median portion (WATANABE 2007: Fig. 7). Apical margin of male abdominal sternite VIII with deep emargination and long median projection (see WATANABE 2007: Fig. 8). Median lobe of aedeagus moderately narrow, parameres wide (see WATANABE 2007: Figs. 9 −11). Body length: 1.80−2.10 mm. Japan. ..................................... A. kanagawana Watanabe, 2007

3 Punctation of elytra distinct near base and scutellum, microsculpture of elytra very coarse. Apical margin of male abdominal sternite VIII straight (Fig. 2). Apical part of median lobe of aedeagus narrow, parameres wide and short (Fig. 8). Body length: 2.10−2.75 mm. China. ................................................................................... A. zhongdianensis sp. nov.

– Punctation of elytra arranged in longitudinal rows, interspaces between punctures with coriaceous microsculpture. Apical margin of male abdominal sternite VIII rounded. Apical part of median lobe of aedeagus wide, parameres narrow, moderately long. ........... 4

4 Pronotum with Y-shaped median elevation and with distinct curved depressions on each side of elevation. Median lobe of aedeagus moderately wide, parameres narrow (WATANABE 1990: Figs 11−12). Body reddish-brown to dark reddish-brown. Body size: 1.90−2.00 mm. Russia and Japan. .................................... A. miyamorii Watanabe, 1990

– Pronotum lacking median elevation, with midline consisting of small punctures, with indistinct longitudinal depressions on each side of midline and with indistinct small lateral depressions. Median lobe of aedeagus narrow, parameres wide (ZHONG et al. 2009: Figs 8−9). Body dark brown. Body size: 1.75−2.18 mm. China. ............................................. ........................................................................... A. wahuiensis Zhong, Zhao & Li, 2009