spermatheca

thumb|Spermatheca of Acanthoscurria geniculata (Brazilian Giant White Knee Tarantula) thumb|Variety of the structure of spermathecae in Phlebotominae (Diptera, Psychodidae) thumb|Female tarantula molt

The spermatheca (pronounced : spermathecae ), also called receptaculum seminis (: receptacula seminis), is an organ of the female reproductive tract in insects, e.g. ants, bees, some molluscs, Oligochaeta worms and certain other invertebrates and vertebrates. Its purpose is to receive and store sperm from the male or, in the case of hermaphrodites, the male component of the body. Spermathecae can sometimes be the site of fertilisation when the oocytes are sufficiently developed.