Pseudovelia vittiformis Ye, Polhemus & Bu, 2013

(Figs. 5, 6, 18)

Pseudovelia vittiformis Ye, Polhemus & Bu, 2013: 302 .

Material examined. VIETNAM, Quang Binh Prov., 3 apterous males, 4 apterous females, Nam Giang district, A Vuong (15°58'N, 107°34'E), 26.V.2015, coll. Zhen Ye (NKUM). CHINA, Hainan Prov.: 1 apterous male, Qiongzhong Li and Miao Autonomous County, Yinggeling Mountain Nature Reserve, 2 XII 2010, coll. Zhen Ye (holotype, NKUM).

Remarks. Presented here is the first record of P. vittiformis from Vietnam. We have examined the holotype of this species; the specimens from Vietnam closely match the description provided by Ye et al. (2013) except that the body sizes of the specimens from Vietnam were relatively smaller (body length: apterous males 2.40–2.44 and apterous females 2.50–2.52). Based on current collection data, this species has two separate populations which are distributed in Hainan Island and central Vietnam. The intraspecific morphological variations (i.e. body size) of these two populations could be the result of long-time isolation without gene flow (i.e. geographical isolation by Beibu Gulf). The addition of molecular data should help to further understand the distinction between the isolated populations of this species.