aedeagus

thumb|Aedeagus of Pentodon idiota thumb|Photomicrograph of the aedeagus of water scavenger beetle [[Tormissus linsi (from above)|right|220px]]

An aedeagus ( or aedeagi) is a reproductive organ of male arthropods through which they secrete sperm from the testes during copulation with a female. It can be thought of as the insect equivalent of a mammal's penis, though the comparison is fairly loose given the greater complexity of insect reproduction. The term is derived .