sphragis
From ZooTerms (Dictionary of Invertebrate Zoology)
sphragis (noun; Greek spragis, seal): (Arthropoda: Insecta) In some Lepidoptera, a structure formed by male glandular secretions or actual male genital parts remaining in the female after insemination that inhibits subsequent copulations of the female; spermatophragma
See also: mating plug.
