In Greek mythology, Cytisorus (Ancient Greek Κυτίσωρος; also Cytissorus, Cytorus) is a son of Phrixus and Chalciope, grandson of Aeetes, and brother of Argus, Melas, and Phrontis. Raised in Colchis, he and his brothers sail toward Orchomenus, join Jason after rescue, and share the flight when the Golden Fleece is taken; Herodotus also knows a Cytisorus who saves Athamas from sacrifice.
Adapted from Wikipedia, "Cytissorus" · CC BY-SA 4.0
I.Phrixid brother on the Argo's return
Apollodorus (1.9.1) names Cytisorus among Phrixus and Chalciope's sons. Apollonius (Argonautica 2.1140–1145) has Argus introduce "Cytissorus, Phrontis, Melas, and me" after the brothers are rescued; they return to Aea and flee with Medea when the Fleece is stolen.
Herodotus (7.197) tells another tale: Cytisorus comes from Aea and delivers his grandfather Athamas from sacrificial death, bringing divine anger on his descendants. Some geographers make him founder or eponym of Cytorus.
II.Homonym care
The atlas id cytisorus-colchis is the Phrixid alone. Keep him distinct from Argus son of Arestor (the shipwright) and from other Colchian Argus nodes.