Interspecific hybrids have been occasionally found in the field. Here were describe a male of the interspecific hybrid between Paracercion sieboldii and P. melanotum with intermediate phenotypes between the two parent species from Japan. Nuclear and mitochondrial DNA analyses indicated that this individual was derived from interspecific mating between a female P. sieboldii and a male P. melanotum. To our knowledge, this is the only report of the hybrid between these two species.