There are five figures in Greek mythology named Argus:
Argus Panoptes guarding the white (or golden) cow Io
LEADER: Here in this Argive land-so runs the tale Io was priestess once of Hera's fane.
Hermes, double-headed Argus Panoptes and Io
1. Argus Panoptes, (Argus "all eyes") was a giant with a hundred eyes. He was thus a very effective watchman, as only a few of the eyes would sleep at a time; there were always eyes still awake. Argus was Hera's servant. His great service to the Olympian pantheon was to slay the chthonic serpent-legged monster Echidna as she slept in her cave (Homer, Iliad ii.783; Hesiod, Theogony, 295ff; Apollodorus, ii.i.2). Hera's last task for Argus was to guard a white heifer from Zeus. She charged him to "Tether this cow safely to an olive-tree at Nemea". Hera knew that the heifer was in reality Io, one of the many nymphs Zeus was coupling with to establish a new order.
To free Io, Zeus had Argus slain by Hermes. Hermes, disguised as a shepherd, first put all of Argus's eyes asleep with boring stories. To commemorate her faithful watchman, Hera had the hundred eyes of Argus preserved forever, in a peacock's tail (Ovid I, 625).
2. Argus (or Argos) is also the name of a long-lived dog owned by Odysseus in Odyssey. When Odysseus returns from his voyages and wears the disguise of a beggar that Athena places upon him, only Odysseus's old dog, Argus, recognizes him and dies afterwards.
3. Argus , the builder of the Argo, the ship of the Argonauts, was according to Apollodorus (ii. 9. §§ 1, 16), a son of Phrixus. Apollonius Rhodius (i. 112) calls him a son of Arestor, and others a son of Hestor or Polybus. (Schol. ad Apollon. Rhod. i. 4, ad Lycophr. 883; Hygin. Fab. 14; Val. Flacc. i. 39, who calls him a Thespian.) Argus, the son of Phrixus, was sent by Aeetes, his grandfather, after the death of Phrixus, to take possession of his inheritance in Greece. On his voyage thither he suffered shipwreck, was found by Jason in the island of Aretias, and carried back to Colchis. (Apollon. Rhod. ii. 1095, &c.; Hygin. Fab. 21.) Hyginus (Fab. 3) relates that after the death of Phrixus, Argus intended to flee with his brothers to Athamas.
4. Argus was the eponym of Argos. The son of Zeus and Niobe, daughter of Phoroneus, he succeeded his uncle Apis as King of Phoronea, which he renamed after himself. According to one account, he married Evadne, the daughter of Strymon and Neaera, and bore Ecbasus, Peiras, Epidaurus and Criasus. According to another account, his wife was nameless, and his sons were Peiras, Phorbas, and Tiryns.
5. Argus was the eldest son of Phrixus and Chalciope, daughter of Aeetes. Argus and his brothers set out to return to their grandfather's kingdom of Orchomenus, but were shipwrecked and rescued by the Argonauts. Argus and his brothers aided Jason and the Argonauts in their quest, and later returned with them to Greece.
Juno and Argus, Peter Paul Rubens, c. 1620
Hermes and Argus, Pyotr Ivanovich Sokolov c. 1775