Noun
A small sac connected with the female reproductive organs of insects and many other invertebrates, serving to receive and retain the spermatozoa.
Source: Webster's dictionaryThe sperm cells are stored in the same area of the gonad as the oocytes until the first oocyte pushes the sperm into the spermatheca (a chamber wherein the oocytes become fertilized by the sperm). Source: Internet
In addition to the greater size of the queen, she has a functional set of ovaries, and a spermatheca, which stores and maintains sperm after she has mated. Source: Internet
The spermatozoa move to the spermatheca in the roof of the cloaca where they remain until ovulation which may be many months later. Source: Internet