Key to species of Parastasia known from Thailand

1 Small to medium in size, total length ˂ 20 mm; elytra with distinct rows of punctures; in lateral view, parameres not bilobed. ................................................................................................... 2

- Large in size, TL ≥ 20 mm; rows of punctures on elytra indistinct (Fig. 51); parameres slightly asymmetric, apex bilobed in lateral view (Figs. 61–62)............................................................ P. birmana Arrow, 1899

2 All claws simple, sickle-shaped without branching (Fig. 58); male aedeagus asymmetric, parameres fused together (Figs. 48–50)............................................................. P. bimaculata (Guérin-Méneville, 1843)

- External claw of meso- and metatarsi bifurcate; aedeagus symmetric or asymmetric, but parameres not fused together..... 3

3 Propygidium and pygidium covered with decumbent setae (Figs. 35–36)......................................... 4

- Propygidium and pygidium without long setae (Fig. 4)........................................................ 7

4 Eyes narrow, ratio of IOD and HW ˃ 0.67 (Fig. 56); antennal clubs distinctly shorter than antennal segment 1–7 combined; mesotarsi of male somewhat enlarged, segment 5 as long as or longer than segment 1–4 combined (Fig. 56); median sac of endophallus membranous without any appendages or spines, but sometimes distinctly with sclerotic surface (Fig. 67)...... 5

- Eyes broad, ratio of IOD and HW ˂ 0.60 (Fig. 57); antennal clubs clearly longer than antennal segment 1–7 combined; mesotarsi simple in both sexes, tarsal segment 5 shorter than segment 1–4 combined (Fig. 60); median sac of endophallus with numerous spines (Fig. 68)................................................................. P. bigibbosa Nonfried, 1891

5 Dorsal surface mostly brownish (Fig. 53); mesotarsi clearly enlarged in male, segment 5 much longer than segments 1–4 combined............................................................................................ 6

- Dorsal surface mostly orange-reddish (Fig. 52); segment 5 of mesotarsi as long as segments 1–4 combined in male......................................................................................... P. anomala Arrow, 1899

6 Ground color of dorsal surface reddish brown to dark brown, posterolateral portions of pronotum with a yellow to testaceous patch; in dorsal view, male aedeagus symmetric. India, Bhutan, China, Vietnam, Laos, and northern Thailand .............................................................................................. P. indica Ohaus, 1898

- Ground color of dorsal surface brownish with dark brown brands on pronotum and elytra (Fig. 53); aedeagus curve and asymmetric. Southern Thailand, Malaysia, Indonesia, and Philippines ................... P. westwoodii Westwood, 1841

7 Ground color of dorsal surface reddish, elytra unicolor (Figs. 1, 55); external margin of parameres sinuate in dorsal view (Figs. 13, 65); in lateral view, ventral margin of parameres plain without distinct concavity (Figs. 15, 66); anterior portion of median sac of endophallus with small spines, remaining followed by large spines (Figs. 16, 70).............................. 8

- Ground color of dorsal surface orange, external and posterior portions of elytra black (Fig. 54); in dorsal view, parameres without concavity (Fig. 63); in lateral view, ventral margin of parameres thickly marginated and deeply concave one-fifth from base (Fig. 64); anterior portion of median sac of endophallus with few large spines, remaining followed by medium spines (Fig. 69)................................................................. P. masumotoi Wada & Muramoto, 1999

8 Scutellum and ventral surface reddish to dark reddish brown (Figs. 1–2, 55); in lateral view, basal of ventral margin of parameres without protrusion.................................................................................... 9

- Scutellum and ventral surface nearly black; in lateral view, basal of ventral margin of parameres clearly protruding backward, process sharp and elongate as spinose formed................................. Parastasia selangorica Kuijten, 1992

9 Rather small in size (Fig. 1); first row of punctures on elytra sinuate; metasternal process stout; in dorsal view, apex of parameres roundly convex (Fig. 13); in lateral view, dorsal and ventral margins almost straight (Fig. 15); median sac of endophallus with a cluster of dense small spines anteriorly, posterior part of median sac with five dark large spines ventrally (Fig. 16)....................................................... P. spinosa Hongsuwong, Sanguansub & Jaitrong, new species

- Medium in size (Fig. 55); first row of punctures on elytra mostly straight; metasternal process sharply produced; in dorsal view, apex of parameres almost truncate with a small carina near internal margin (Fig. 65); in lateral view, dorsal margin weakly concave, while ventral margin convex (Fig.66); median sac of endophallus with sparse small spines anteriorly, ventral of posterior part without dominantly large spines (Fig. 70).................................... sulcipennis Gestro, 1888