New species of Calloserica Brenske, 1894 from Sikkim and Nepal (Coleoptera, Melolonthidae, Sericini)

Four new species of the genus Calloserica Brenske, 1894 are described: Calloserica bertiae n. sp. (Sikkim), Calloserica lachungensis n. sp. (Sikkim), Calloserica cambeforti n. sp. (Sikkim) and Calloserica delectabilis n. sp. (Nepal). C. bertiae n. sp. and C. lachungensis n. sp. differ from each other by size of parameres and aedeagus, both can be distinguished from the genitalitary very similar C. brendelli Ahrens, 1999 by the shorter parameres. In contrast to all other Calloserica species, C. delectabilis n. sp. is characterized by an erect lamina on ventral portion of aedeagal phallobasis. In C. cambeforti n. sp., the lateral apophysis of aedeagal phallobasis is ventrally largely produced and curved, apically not produced, the parameres are shorter than those of C. trigrina Brenske. A checklist of the genus Calloserica, new records of C. trisuliensis Ahrens, C. brendelli Ahrens, and C. tigrina Brenske and a modified key to the species are given. Male genitalia of the new species and the distribution of all species of the genus are illustrated.