Key to the species of Eotrechinae (Hemiptera: Heteroptera: Gerridae) of Thailand and review of the fauna of the Phetchabun Mountain Range Author Nakthong, La-Au Author Vitheepradit, Akekawat Author Sites, Robert W. text Zootaxa 2014 3860 1 47 63 journal article 10.11646/zootaxa.3860.1.2 a26eaf5f-4eba-45ad-8806-dd7288d78493 1175-5326 287060 B9713C6D-BC3B-4EF2-8495-8BDCD535A80D Onychotrechus esakii Andersen Figs. 5 , 7 Onychotrechus esakii Andersen 1980 : Steenstrupia 127–128. Diagnosis. This species can be recognized by the sublateral light stripes of the mesonotum reaching the mesonotal hind margins in the apterous form ( Fig. 5 ). It may be distinguished from congeners in Southeast Asia by the boldly contrasting and dark color pattern, whereas in O . pallidus Andersen (known from Malaysia ), the pattern is reduced and color pale. Discussion. This species has been recorded from China , Malaysia , Thailand , and Vietnam ( Andersen 1980 ; Zettel & Chen 1996 ; Cheng et al. 2001 ; Cheng et al. 2006 ). In Thailand , O . esakii has been recorded from waterfalls in northern, central, northeastern, and southern Thailand ( Andersen 1980 , Vitheepradit 2000 ). This species, as well as its congeners, are typically found on rock surfaces in streams or rock walls splashed by waterfalls ( Andersen 1980 , Vitheepradit 2000 ). In this study, this species is widespread throughout the mountain range. Material examined. THAILAND : Chaiyaphum Province : Nam Nao NP, stream before Heaw Sai Waterfall, 16°40’N 101°41'E , 566 m , 5-V-2004 , A. Vitheepradit, L-665 (1 wingless male); Loei Province : Amphur Phu Rua, Song Korn Waterfall, 17°21’N 101°24'E , 728 m , 10-V-2004 , A. Vitheepradit and T. Prommi, L-676 (4 winged males, 4 wingless males, 1 winged female, 2 wingless females); Phu Rua NP, Sam Chan Waterfall, 17°29’N 101°20'E , 1147 m , 20-XII-2012 , KU team, C-233 (10 winged males, 16 winged females); Phetchabun Province : Nam Nao NP, stream behind visitor center, 16°44'N 101°34'E , 820 m , 9-III-2002 , A. Vitheepradit, L-275 (1 wingless female); Tad Mok NP, Song Nang Waterfall, 16°22’N 101°22'E , 800 m , 30-IV -2004 , A. Vitheepradit, L- 654 (1 winged male); Nam Nao NP, Sum Ma Cow, 16°41'N 101°40'E , 562 m , 20-XII-2012 , KU team, C-238 (1 wingless female); Phitsanulok Province : Phu Hin Rongkla NP, Waterwheel Fall and stream, 16°59’N 101°00'E , 1280 m , 10-III-2002 , R.W. Sites, A. Vitheepradit, and K. Kirawanich, L-285 (1 winged female); Phu Hin Rongkla NP, Romglao Waterfall, 16°59’N 101°00'E , 1190 m , 11-III-2002 , R.W. Sites, A. Vitheepradit and K. Kirawanich, L-288 (1 winged male, 1 winged female); Phu Hin Rongkla NP, Nam Tok Palad, 16°59’N 101°00'E , 300 m , 12-III- 2002 , R.W. Sites, A. Vitheepradit and K. Kirawanich, L-289 (1 winged male); Phu Hin Rongkla NP, Huai Kha Mheun, 16°59’N 101°00'E , 1253 m , 6-V-2003 , A. Vitheepradit and T. Prommi, L-505 (8 winged males, 1 wingless male, 6 winged females, 3 wingless females); Phu Hin Rongkla NP, Romglao Waterfall, 16°59’N 101°00'E , 1190 m , 6-V-2003 , A. Vitheepradit and T. Prommi, L-507 (1 wingless female).