1.	First tergite and basal half of second tergite ivory (Fig. 19); length of first metasomal tergite about 1.4 times as long as wide apically	Bassus albobasalis sp. n.
–	First tergite largely black or dark brown (Figs 13, 14, 29); length of first tergite 1.5–2.0 times as long as wide apically	2
2.	Dorsal carinae of first metasomal tergite largely obsolescent medially and posteriorly (Figs 13, 14); propodeum black; notauli narrowly crenulate; mesoscutum uneven medio-posteriorly; hind tibial spurs brown and weakly contrasting with blackish hind basitarsus	Bassus albifasciatus (Watanabe, 1934)
–	Dorsal carinae of first tergite costate medially and posteriorly nearly complete (Fig. 29); propodeum (except more or less posteriorly) brownish-yellow; notauli moderately widely crenulate (Fig. 28); mesoscutum flattened medio-posteriorly (Fig. 28); hind tibial spurs pale yellowish and distinctly contrasting with blackish hind basitarsus	Bassus albozonatus sp. n.