(Ἀπόμυιος) "driving away the flies," a surname of Zeus at Olympia. On one occasion, when Heracles was offering a sacrifice to Zeus at Olympia, he was annoyed by hosts of flies, and in order to get rid of them, he offered a sacrifice to Zeus Apomyius, whereupon the flies withdrew across the river Alpheius. From that time the Eleans sacrificed to Zeus under this name. (Paus. 5.14.2.)
[L.S]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890