epigynum
From ZooTerms (Dictionary of Invertebrate Zoology)
epigynum also epigynium (noun; plural epigyna; Greek epi, upon; gyne, woman): (Arthropoda: Chelicerata) 1. A sclerotized structure of certain female spiders and mites, variable in form, covering the genital opening. 2. In mites also referred to as epigynial plate or genital plate.
