(Figs 1E, 4B, 18C, 26S, 42A, 58F, 65G, H, 72B)

Semnostoma poecilopa Meyrick, 1918: 128; 1925: 103; Gaede, 1937: 307; Clarke, 1969: 367. TL: Assam, India. TD: NHMUK. Comb. nov.

Type material (Figs 65G, H, 72B). Lectotype ♀, INDIA, Assam, Khasi Hills, ix.1906, genitalia slide no. J. F.G.C. 8385 (NHMUK).

Additional material examined. CHINA: Yunnan Province: 5 ♂♂, 2 ♀♀, Mt. Xiaohei, 2300 m, Longling County, 10.viii.2005, leg. Yingdang Ren, genitalia slide nos. ZJL05391f, ZJL05392m; 2 ♂♂, 3 ♀♀, Xiaoheishan Nature Reserves (24.52°N, 98.84°E), 1974 m, Longling County, 18−19.vii.2013, leg. Shurong Liu, Yuqi Wang and Kaijian Teng, genitalia slide no. 16135m; 2 ♂♂, 1 ♀, Taiyanghe Nature Reserves (22.79°N, 100.98°E), 1450 m, 30.v−19.viii.2014, leg. Zhenguo Zhang; 1 ♀, Yexianggu (22.17°N, 100.87°E), 762 m, Xishuangbanna, 13.vii.2015, leg. Kaijian Teng and Xia Bai; 2 ♂♂, 1 ♀, Baoshan (24.82°N, 98.78°E), 2009 m, 9, 17.viii.2014, leg. Kaijian Teng, Shurong Liu and Hua Rong, genitalia slide no. LGE18178f; 54 ♂♂, 27 ♀♀, Linjiapu (25.29°N, 98.70°E), 2144 m, Tengchong County, 14−16.viii.2014, leg. Kaijian Teng, Shurong Liu and Hua Rong, genitalia slide nos. LGE16136f, LGE18172f, LGE 19029m; 7 ♂♂, 3 ♀♀, Baoshan (24.82°N, 98.78°E), 2009 m, 16, 17.vii.2015, leg. Kaijian Teng and Xia Bai, genitalia slide nos. LGE 16128m, LGE 18171m, LGE18173; 13 ♂♂, 4 ♀♀, Xiaoheishan Nature Reserves (24.52°N, 98.84°E), 1974 m, Longling County, 27−30.vii.2015, leg. Kaijian Teng and Xia Bai, genitalia slide no. LGE16129f; Xizang Autonomous Region: 1 ♂, Pai Town (29.51°N, 94.86°E), 2900 m, Milin County, 1.viii.2010, leg. Houhun Li et al., genitalia slide no. LGE16134; 1 ♀, 80K (29.66°N, 95.49°E), 2059 m, Motuo County, 8.viii.2017, leg. Mujie Qi and Xiaofei Yang.

Diagnosis. Adult (Figs 1E, 4B, 18C). Wingspan 10.0−13.0 mm. This species is unique in the genus as both sexes have long scale tuft on the ventral surface of the labial palpi (Fig. 1E). It is striking that segment III of the labial palpi is white-banded, and the forewing ground is brassy yellow marked with white streaks and spots. The general coloration and the markings of T. poecilopa are similar to those of T. leucochalca (Meyrick, 1918) described from India, but the markings are more distinct and a white spot near the base of costa is absent in the former. The male genitalia (Fig. 42A) are diagnosed by the fan-shaped uncus, the narrow valva evenly elongated from base to 2/3 and the elliptical anellus lobe. The female genitalia (Fig. 58F) are typical to the pancratiastis -group in having a spinous segment VIII, strongly produced anterior margin of sternum VIII, a small sclerite at the base of ductus bursae and a round signum consisting of minute denticles, but the corpus bursae are somewhat smaller and the signum is situated more posteriorly compared to its congeners.

Variation. The forewings can be strongly or weakly mixed with fuscous.

Distribution. China (Yunnan, Xizang), India.

Remarks. Thiotricha poecilopa and a related species T. scatebrosa are unusual in the genus as both sexes have a tufted segment II of the labial palpi. The two species were originally described in the genus Semnostoma along with T. leucochalca and T. barathrota, but that genus was synonymized with Thiotricha by Lee et al. (2021). Here we propose new combinations for the four species: T. barathrota (Meyrick, 1918) comb. nov., T. leucochalca (Meyrick, 1918) comb. nov., T. poecilopa (Meyrick, 1918) comb. nov. and T. scatebrosa (Meyrick, 1918) comb. nov. Thiotricha poecilopa is recorded from China for the first time in this study.