The first Asian species of Polycaon Castelnau, and a new montane species of Melalgus Dejean from China (Coleoptera: Bostrichidae: Polycaoninae) Author Liu, Lan-Yu Department of Science Communication, National Pingtung University- Pingshi Campus, No. 1, Linsen Rd, Pingtung City, Pingtung County 90049, Taiwan Author Beaver, Roger A. 161 / 2 Mu 5, Soi Wat Pranon, T. Donkaew, A. Maerim, Chiangmai 50180, Thailand text Zootaxa 2023 2023-07-10 5315 3 271 281 http://dx.doi.org/10.11646/zootaxa.5315.3.5 journal article 58478 10.11646/zootaxa.5315.3.5 27c8db3e-eaa9-4a88-a65c-0a4d99a18c0a 1175-5326 8130647 3B99C8B1-72B1-4D90-86EE-11EC31FD95AA Melalgus batillus ( Lesne, 1902 ) Heterarthron batillum Lesne, 1902: 223 . Melalgus batillus (Lesne) : Rai, 1967: 22 . Heterarthron talpula Lesne, 1911: 47 . Synonymy: Borowski & Węgrzynowicz, 2012: 439 . Melalgus japonicum [sic] Chûjô, 1973: 10 . syn. n. Taxonomy. The male holotype of M. batillus (MNHN) has been examined by LYL, and we have examined further specimens of both sexes from China ( Hong Kong , Zhejiang). Melalgus japonicum [ sic ] Chûjô was described from a single male in a very brief paper in Japanese ( Chûjô 1973 ). He compared the species with M. batillus , noting differences in the head, mentum and elytra without specifying what the differences were. The paper was overlooked by Borowski & Węgrzynowicz (2007) , as noted by Ivie (2010) , and the species omitted from the treatment of the genus by Borowski & Węgrzynowicz (2012) . The holotype was redescribed and illustrated by Yoshitomi (2021) , together with further specimens of both sexes from Japan . It is evident from Yoshitomi’s (2021) excellent description, photographs, and illustrations of the male genitalia, that the species falls within the range of intraspecific variation of M. batillus , a species which is rather variable in size and details of morphology.Accordingly, we here synonymise M. japonicus with M. batillus . New record. CHINA : Hong Kong , Fu Tei BBQ Area , 22.40577[N], 113.98865[E], 139m , 21‒28.iv.2022 , FIT Vane, MTH[amer]/MR[Liang], FTB2V1–3 ( 1 female ) . Distribution. China ( Hainan , Hong Kong , Zhejiang), India ( Assam ), Japan , Vietnam . Biology. Beeson & Bhatia (1937) obtained adults in March from the cut branch wood of Vatica lanceifolia (Roxburgh) Blume ( Dipterocarpaceae ).