16. Zeus’s Wife Visited Her Vengeance Upon His Mistress With a Gadfly
To lull Argus Panoptes to sleep, Hermes set out to shoot the breeze with the many-eyed giant. He played the flute and told stories to get him to relax, and Argus began to shut his hundred eyes, one by one. When the giant was finally zonked out, Hermes grabbed a stone and smashed his head in. He then freed Io from her tether so Zeus could get some loving time with his cow mistress. A lived Hera found out what had happened, and sent a gadfly to torment the heifer and sting her nonstop.
A gadfly might not seem like much vengeance, but Zeus’ wife knew what she was doing. The constant buzzing and biting drove the bovine Io mad with pain, and forced her to wander the earth in an attempt to escape the irritant. She swam the straits between Europe and Asia, which became known as the Bosporus (Greek for “ford of the cow”), and the sea southwest of Greece, which became known as the Ionian Sea. She eventually swam to Egypt, where Zeus finally restored her to human form. There, Io bore Zeus a son and daughter, who gave rise to a line of legendary descendants whose numbers include Hercules.