1	Elytron with six discal striae and a submarginal stria (6+1). Median lobe of aedeagus simple, without division into dorsal and ventral sclerites, sometimes with a median process on ventral side	2
–	Elytron with number of striae and degree of their development very variable among species and within one species (0–11 + 0–1). Median lobe of aedeagus complex, with evident dorsal and ventral sclerites, which apically divided into two parts of different shape	3
2	Smaller (TL: 5.0–5.7 mm), broader species (Figs 5, 6). Median lobe of aedeagus with a median, hammer-like process on ventral side (Fig. 19)	portior
–	Larger (TL: 5.8–6.8 mm), more elongate species (Figs 7, 8). Median lobe of aedeagus simple, hook-like, without process (Fig. 20)	tulagicus
3	Elytron with striae. Dorsal sclerite of median lobe of aedeagus with rugose surface sculpture distinctly visible in lateral view; apexes of two parts of dorsal and ventral sclerites without strong modification, elongate, more or less pressed together (Figs 15–17)	4
–	Elytron with or without striae. Dorsal sclerite of median lobe of aedeagus without surface sculpture, smooth; apexes of two parts of dorsal and ventral sclerites differently modified, usually disposed more freely (Figs 18, 20, 21)	6
4	Larger species (TL: 6.3 mm). Elytron black with large subapical testaceous spot; with 11 dorsal and a submarginal stria (Fig. 3). Male genitalia as in Fig. 17	kietensis sp. nov.
–	Smaller species (TL: 5.2–6.2 mm). Elytron brownish black with testaceous transverse basal band, or almost uniformly ferruginous; with 11 dorsal striae and with or without submarginal stria (Figs 1, 2)	5
5	More parallel species; disc of elytra brownish black (Fig. 1). Median lobe of aedeagus and paramere broader, with more rounded apexes (Fig. 15)	baranensis sp. nov.
–	More oval species; disc of elytra ferruginous, darker along striae (Fig. 2). Median lobe of aedeagus and paramere more elongate and slender apically (Fig. 16)	bougainvillensis sp. nov.
6	Elytra without striae	7
–	Each elytron with 11 dorsal and a submarginal stria. The striae can be reduced or additional strioles can be present (Figs 10–12). Male genitalia as in Fig. 22	variistriatus sp. nov.
7	Smaller (TL: 5.1 mm), more oval species (Fig. 9). Male genitalia as in Fig. 21	urceolus sp. nov.
–	Larger (TL: 6.3–7.2 mm), more parallel species (Fig. 4). Male genitalia as in Fig. 18	laevipennis sp. nov.