Belenus angulatus Distant

Belenus angulatus Distant 1909 p . 116

Belenus bengalensis Distant 1909 p . 117, new synonymy

Material examined. 1F, Bien Hoa, 25.II.1969, at light, C.R. Joyce coll. (BPBM); 1F, Bien Hoa, 10.IX.1969, at light, C.R. Joyce coll. (BPBM). 1 spec, prov. Nam ha, TuongLinh, nr. Phu Ly, N° 565, 25 /V/1966, leg. Topal (HMNH). 1F + 1M, Cuc Phuong, 14/09/14, 21°27’30.7”N – 105°38’43.4”E, light trap, Ouvrard & Soulier rec., (MNHN); 1F + 1M, Cuc Phuong, Milinh station, 10/09/14, 21°23’30”N – 105°42’42”E, light trap, Bourgoin rec. (MNHN); 1F, Cuc Phuong, 11/09/14, 20°15’01”N – 105°42’52”E, light trap, Bourgoin rec. (MNHN); 1M, Cuc Phuong, 13/09/14, 20°21’01”N – 105°35’38”E, light trap, Bourgoin rec. (MNHN).

Discussion. Belenus angulatus and Belenus bengalensis, described by Distant (1909). were separated by the size of the costal area and colour. The two types, deposited at the Natural History Museum, London, exhibit these slight differences. The type of B. bengalensis is distinctly darker and the costal and subcostal areas are slightly wider. However, long series of collected specimens of both species show variation in the size of the costal area and apical angles of the paranota, without variation in colour, and conversely, variation of colour with the same size of costal area and paranotal angles, indicating that these characters are not suitable for separating species. In addition, the two species share almost the same distribution: B. angulatus is known from Burma and New Guinea, whereas B. bengalensis is known from India, Thailand, and New Guinea (Drake & Ruhoff 1965a). Therefore, B. bengalensis is here synonymized under the name of B. angulatus .