Artemis, one of the key figures of the female Greek pantheon, is the ancient virgin goddess of the hunt, wilderness, animals, childbirth, and a protector of young girls, later associated with the moon. Artemis is the equivalent to the Roman Diana, but a fresher and more distinctive, if offbeat, choice.
Artemis was the twin sister of Apollo, one of the twelve deities who lived on Mount Olympus. She features in three of the fifth century plays of Euripides.
Artemas, on the other hand, is a male name, though some gender confusion could arise from the Artemis Fowl novels.