Hyginus, Astronomica 2.2
In the meantime in the district of the Athenians many girls without cause committed suicide by hanging, because Erigone, in dying, had prayed that Athenian girls should meet the same kind of death she was to suffer if the Athenians did not investigate the death of Icarius and avenge it. And so when these things happened as described, Apollo gave oracular response to them when they consulted him, saying that they should appease Erigone if they wanted to be free from the affliction. So since she hanged herself, they instituted a practice of swinging themselves on ropes with bars of wood attached, so that the one hanging could be moved by the wind. They instituted this as a solemn ceremony, and they perform it both privately and publicly, and call it alétis, aptly terming her mendicant who, unknown and lonely, sought for her father with the God. The Greeks call such people Alétides.