Binhon atrum Pic – a junior synonym of Plastocerus thoracicus, with nomenclatural notes on Plastocerus (Coleoptera: Elateridae: Plastocerinae)

//Binhon atrum// Pic, 1922, an enigmatic genus and species described in the family Dascillidae based on a single female from Vietnam, is illustrated, diagnosed and formally synonymised with //Plastocerus thoracicus// Fleutiaux, 1918 (Elateridae: Plastocerinae). The species is recorded from China (Guangxi, Yunnan) for the first time. The taxonomic history of the genus //Plastocerus// Schaum, 1852 (not //Plastocerus// LeConte, 1853) with emphasis on its synonyms, is briefly summarised