Key to species of Olophrum laxum group (modified Shavrin & Smetana 2017)

1 Head with slightly protruded eyes and extremely flattened postocular ridges. Aedeagus (Fig. 3) with very wide internal sac. Body length: 4.65 mm. Habitus as in Fig. 1. Nepal......................................... O. lama Shavrin, sp.n.

- Head with distinctly protruded eyes, with obtuse or sharp well-defined postocular ridges. Aedeagus with moderately narrow internal sac. Chinese species............................................................................. 2

2 Head without or with very short, fine grooves in front of ocelli................................................. 3

- Head with moderately long, deeper grooves in front of ocelli, reaching (at least almost) midlength of eye............... 4

3 Punctation of pronotum small and sparse. Aedeagus with apices of parameres about reaching apex of median lobe (see Shavrin & Smetana 2017: Fig. 6) Body length: 3.79–5.02 mm. Habitus as in Fig. 3 (see Shavrin & Smetana 2017). Hubei, Shaanxi, Sichuan .................................................................. O. pacei Shavrin & Smetana, 2017

- Punctation of pronotum moderately large, coarse and dense. Aedeagus with long parameres significantly exceeding apex of median lobe (Fig. 5). Body length: 3.70–4.64 mm. Habitus as in Fig. 2. Shaanxi, Gansu ......... O. schuelkei Shavrin, sp.n.

4 Head behind sharp postocular ridges markedly narrowed toward neck. Lateral margins of pronotum evenly narrowed anteriad and posteriad, disc with vague transverse mediobasal impression. Apices of parameres slightly exceeding apex of median lobe

(see Shavrin & Smetana 2017: Fig. 5). Body larger: 4.2–4.5 mm. Habitus as in Fig. 2 (see Shavrin & Smetana 2017). Yunnan..................................................................... O. hromadkai Shavrin & Smetana, 2017 - Head behind somewhat obtuse postocular ridges moderately narrowed toward neck. Lateral margins of pronotum markedly more narrowed anteriad than posteriad, disc with indistinct to distinct, deep transverse impression. Apices of parameres distinctly exceeding apex of median lobe (see Shavrin & Smetana 2017: Fig. 4) Body smaller: 3.40–4.25 mm. Habitus as in Fig. 1 (see see Shavrin & Smetana 2017). Sichuan, Shaanxi, Yunnan...................... O. laxum Shavrin & Smetana, 2017