Picture of Why Hermes is Hermes Argeiphontes.
Hermes Kills Argus. Image ID: 1624645. Mercury kills Argus, who is represented with his body covered with eyes. (1844-1861). Fourquemin, fl. 1835-1853 -- Lithographer
Housselin, Alexis Louis Pierre -- Engraver.
NYPL Digital Gallery
In epic poetry, the epithet argeiphontes is sometimes substituted unambiguously for the name of Hermes. Traditionally, "argeiphontes" is said to mean "Argus-slayer" and in the accompanying picture, you can see why, assuming you recognize the guy with the sword as Hermes.
Argus, child perhaps of Zeus and Niobe, is the eponymous creature of Argos (Oxford Classical Dictionary). You may be familiar with him as Argus Panoptes, the many-eyed monster whose eyes came to grace the tail of Hera's peacock after Hermes killed him. Argus was standing watch over Io on Hera's orders. Zeus wanted access to Io, so he sent his son Hermes to get rid of the guard.
For more, see Thursday's Term to Learn - Argeiphontes
