In Greek mythology, Lynceus was a prince of Egypt, son of Aegyptus, and the only one of Aegyptus' fifty sons to survive the Danaids' wedding-night massacre. Spared by Hypermnestra, he became king of Argos after Danaus and, through their son Abas, founded the Danaid–Abantiad line that leads toward Perseus. He is distinct from Lynceus the keen-eyed Apharetid Argonaut.
Adapted from Wikipedia, "Lynceus (son of Aegyptus)" · CC BY-SA 4.0
I.Family
Lynceus is one of fifty sons of Aegyptus; Apollodorus names Argyphia as mother of Lynceus and five full brothers (Proteus, Busiris, Enceladus, Lycus, Daiphron). Aegyptus is twin of Danaus, so Lynceus marries his cousin, the Danaid Hypermnestra (Amymone in a rare pairing). Their son Abas succeeds him as king of Argos.
Homonym care: lynceus-apharetid in this atlas is the Messenian Argonaut of supernatural sight, brother of Idas — a different figure entirely.
II.Wedding night and flight
Aegyptus sent his sons to force the marriages Danaus had refused. Under siege Danaus consented to a mass wedding but armed the Danaids to kill their husbands in sleep. Forty-nine sons died; Hypermnestra spared Lynceus — often because he respected her virginity — and helped him flee to Egypt or to Lynceia in the Argolid. Torch signals between Lynceia and Larissa mark their mutual safety; the town was said to take his name.
Ovid's Heroides 14 gives Hypermnestra's letter from that night.
III.Kingship
In one strand Lynceus and Aegyptus return with an army and Lynceus kills Danaus before uniting with Hypermnestra and taking the throne. Apollodorus instead has no invasion: Danaus dies in time and the crown passes peacefully to Lynceus, then to Abas.
Through Abas the Argive stem runs toward Acrisius, Danae, and Perseus.