The spermatheca is part of the female reproductive organs.
It is the place, where the sperms are stored, after they entered
through the spermathecal duct [D]. Sometimes the spermatheca
is paired [taxonomical importance]. It is a cuticular organ.
When an egg passes along the oviduct, stored sperm from the
spermatheca is released and moves into the bursa copulatrix.
A ring of glands is surrounding the bulga and secrets nutrient
material into the lumen, before the organ receives sperm.
Fine ridges in the bulga. These corrugations are filled with
secretion from the spermathecal glands in mature fleas, and
the sperms are packed tightly between those ridges.