Epigyne

The epigyne or epigynum is the female genital opening in spiders.

It is of special interest to people who study spiders because the exact shape of the epigyne is often the only way to determine the exact species within a genus. The palps of male spiders have a similar importance in determining species.

This is a consequence of the mating habits of spiders which do not include normal copulation by joining the sexual openings of male and female; instead the male deposits his sperm on a specially built little web and sucks it up in his palp, after which he is ready for courtship. The palp must fit the epigyne.