This study provides an updated description of the type species of Weiseronyssus Samšiňák, W. mirus Samšiňák, with redescription of the female and male based on paratype slides and newly-collected mites. Specimens of W. mirus were collected in China from laboratory-reared Allomyrina dichotoma (Coleoptera: Scarabaeids: Dynastinae) larvae. A key to both sexes of Weiseronyssus species is provided.