The adult stages of Multidendrolaelaps bialowiezae (Hirschmann et Wiśniewski) comb. nov. are described for the first time on the basis of specimens from Slovakia. The species was originally known from phoretic deutonymphs found on a cerambycid beetle in Poland and was placed in the subgenus Insectolaelaps Shcherbak. The female of M. bialowiezae is characterized by a modified laelapid type of sperm access system associated with the coxae III, which is specific to the digamasellid genus Multidendrolaelaps Hirschmann, and therefore the species is newly transferred to this genus. Some interspecific morphological characters that could be used to distinguish the deutonymphs of the (sub)genera Multidendrolaelaps and Insectolaelaps are discussed.