According to Apollodorus, Hephaestus attempted to rape Athena but was unsuccessful. His semen fell on the ground, impregnating Gaia, who gave birth to Erichthonius, the future king of Athens. Gaia didn't want the infant, so she gave it to Athena. Athena in turn gave the baby in a small box to three sisters, Herse, Pandrosus, and Aglaulus, warning them to never open it. Aglaulus and Herse opened the box despite these instructions, went insane at the sight, and threw themselves off the Acropolis.
P. Rubens, The daughters of Cecrops finding the infant Erichthonius of Athens, 1616
An alternative version of the same story is that, while Athena was away from Athens, bringing a mountain from Pallena to use in the Acropolis, the sisters, minus Pandrosus again, opened the box. A crow witnessed the opening and flew away to tell Athena, who fell into a rage and dropped the mountain (now Mt. Lykabettos). As in the first version, Herse and Aglaulus went insane and threw themselves off a cliff to their deaths.
Pandrosus and Hermes later had a son, Ceryx.