Taxonomic study on the subspecies of Cyclommatus metallifer (Boisduval, 1835) from Indonesia (Coleoptera: Lucanidae)

The lucanid beetles of the subspecies of Cyclommatus metallifer from Indonesia are revised here. Five subspecies are known from Indonesia. Among them, Cyclommatus metallifer otanii Mizunuma and Nagai was confirmed to be a synonym of Cyclommatus metallifer aenomicans Parry. Moreover, a new subspecies, Cyclommatus metallifer butonensis ssp. nov., is described from Buton Island of Indonesia. The identification key, distributional data, photos of adults, genitalia, and figures for each subspecies are provided.