Leiodidae (Coleoptera) of the Hainan Island with new faunistic records from China and with notes on the unique body modifications in the genus Agathidium

Agathidium (Agathidium) pilulum sp. nov., Agathidium (Macroceble) cornigerum sp. nov., Agathidium (Macroceble) apiforme sp. nov., and Dermatohomoeus pennatus sp. nov. from Hainan Island (China) are described and distinguished from other similar species. A key for identification of the Leiodidae subfamilies, tribes, genera and species occurring in Hainan is provided. Unique morphological modifications of the legs and the male genitalia in Agathidium Panzer, 1797 from Hainan are illustrated and discussed. New faunistic records of the genus Agathidium from the mainland China are also presented: Agathidium (Agathidium) formosum Angelini & De Marzo, 1984 from Jiangxi, Agathidium (Microceble) venustum Angelini & De Marzo, 1995 from Sichuan, Agathidium (Agathidium) kabateki Angelini, 2000 from Yunnan, and Agathidium (Agathidium) puetzi Angelini & Švec, 2000 from Gansu.