Description. Holotype female (macropterous). Body length 4.2 mm. Body uniform brown; antennal segment III yellow, but brownish apically, IV yellow at basal half, brown at apical half, V yellow at basal 1/3, rest of antennae uniform brown (Fig. 10); tube darkest; all major setae yellowish-brown.

Head. Head about two times as long as wide (Figs 1, 8); head elongate, preocular projection about 1.4 times as long as wide; compound eyes prolonged posteriorly on ventral surface (Fig. 1); interocellar setae well developed, longest setae on head, pointed at apex; postocular setae small, not reaching posterior margin of eyes, pointed at apex, arise behind inner margin of eyes; cheeks with several pairs of spine-like setae (Fig. 1). Antennae 8-segmented, slender, segment III longest, about 5 times as long as wide, III with 1+1 sense cone, IV with 2+2 (Figs 2, 10). Mouth-cone short and rounded, maxillary stylets V-shaped, retracted into head one third way to posterior margin of eyes (Fig. 1).

Thorax. Pronotum almost smooth, notopleural sutures complete (Figs 1, 8), aa and am slightly developed, pointed at apex, ml and pa developed, longer than aa, pointed at apex, epim well-developed, blunt at apex; basantra surround mouth-cone, ferna developed (Figs 1, 12). Mesopresternum boat-shaped (Figs 4, 12). Metanotal median setae well developed, metanotum smooth anterior middle, metathoracic sternopleural sutures absent. Fore wing broad, three pairs of sub-basal setae pointed at apex, S1 smaller, shorter than S2, S3 longest (Fig. 3), with 15–16 duplicated cilia. All tibia and tarsus without tooth.

Abdomen. Pelta triangular, with entire reticulation (Figs 5, 11); abdominal tergites II–VII dorsal with reticulation in front half, each with two pairs of wing-retaining setae (Fig. 11); tergite IX setae almost as long as tube; tube smooth, shorter than head, anal setae about as long as tube (Figs 7, 13).

Measurements (holotype female in microns). Body length 4200. Head length 540, width across eyes 240; preocular projection length 170, width 125; eyes length 130, ventral length 180; postocular setae length 20. Antennae length 810, segment I–VIII lengths (maximum width) 70 (50), 80 (40), 170 (35), 140 (35), 115 (30), 90 (30), 65 (30), 65 (20). Pronotum length 225, width 300, length of pronotal setae, am 10, aa 15, ml 30, epim 75, pa 35. Metanotal median setae length 15. Fore wing length 1470, sub-basal setae S1– S3, 20, 55 and 90. Abdominal sternite IX S1–S3 length, 375, 445 and 265, tube length 375, basal width 115, at apex 60, anal setae length 410.

Male (macroptera). Very similar to female, but smaller, fore tarsal without tooth (Figs 9, 14).

Measurements (paratype male in microns). Body length 3860. Head length 505, width across eyes 230; preocular projection length 145, width 120; eyes length 115, ventral length 160; postocular setae length 20. Antennae length 740, segment I–VIII lengths (maximum width) 70 (50), 75 (35), 160 (35), 125 (35), 95 (30), 70 (30), 60 (25), 60 (20). Pronotum length 180, width 270, length of pronotal setae, am 15, aa 15, ml 25, epim 65, pa 35. Metanotal median setae length 20. Fore wing length 1120, sub-basal setae S1– S3, 20, 50 and 65. Abdominal sternite IX S1–S3 length, 265, 310 and 215, tube length 305, basal width 105, at apex 60, anal setae length 300.

Material examined. Holotype ♀, China, Hunan, Yongzhou, Dupangling National Nature Reserve (25.46°N, 111.37°E; elev. 380 m), from the root of Poaceae grasses (Fig. 15), 4.IX.2020, coll. Xia Wang. Paratype. 1♂, same data as holotype.

Etymology. This species name is composed of the Latin word, “ elongatus ”, based on its elongated preoclular projection of head.

Comments. This new species can be recognized as the genus Ophthalmothrips by the elongated preocular projection of the head, which is about 1.4 times as long as its wide. Similarly, this character is also present to O. faurei and O. longiceps. But the new species differs by having postocular setae small (not reaching at posterior margin of eyes), interocellar setae, pronotal epimal setae well-developed and pelta triangular with slightly rounded laterally. In O. faurei, the original description showed that it had postocular setae well-developed (Ananthakrishnan, 1964); Ananthakrishnan (1973) redescribed both sexes of O. faurei in detail, of which its postocular setae were also developed, interocellar setae absent, and one pair of median dorsal setae of head well-developed (but we think that these setae were probably located ventrally.); Haga (1975) studied Ananthakrishnan’s specimens of O. faurei, and showed that the pronotal epimeral setae are small and the interocellar setae developed. The genus Ophthalmothrips was reviewed worldwide by Minoura & Mound (2019) as the latest research. They recorded only one female represented as O. faurei from Guilin City in China, but the author helped to re-check this specimen, and found its head was too dark to see any characters. And the specimens from Japan identified as O. faurei together with Chinese specimen showed developed postocular setae. Thus, the only female specimen identified as faurei need to further study in the future. In O. longiceps, it is distinguished from O. elongatus Li & Dang, sp. nov. by the shorter preocular projection (wider than long), the well-developed postocular setae, and the pelta sharply pointed laterally.

Figures 16–25. Ophthalmothrips formosanus (16–17, 21–22, 24), O. miscanthicola (18, 20, 23) and O. longiceps (19, 25). 16. Head and pronotum; 17–19. Antenna; 20, 22. Fore leg, female; 21. Fore leg, male; 23–25. Pelta.