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) .