Sinuatus group

Diagnosis. Body medium-sized (4.9–6.5 mm), with slightly transverse pronotum and moderately wide elytra slightly longer than broad; aedeagus with very wide median lobe and narrow parameres extending beyond apex of median lobe, internal sac with moderately short and sclerotized flagellum.

Species included. G. sinuatus (Sharp, 1889), G. suensoni Bernhauer, 1936 .

Distribution. Species of the sinuatus group are distributed in North and Central Japan: Hokkaido and Honshu islands.

Bionomics. Detailed bionomic data are unknown.

Remarks. In the presence of a strongly sclerotized flagellum, the sinuatus group is somewhat similar to the plagiatus and aokii groups, but differs by having a significantly broader median lobe. In the narrow parameres, it is similar to the aokii group, but differs by a larger body and broader elytra.