Apollodorus Library 3.8.2

[2] But when Nyctimus succeeded to the kingdom, there occurred the flood in the age of Deucalion; ¹ some said that it was occasioned by the impiety of Lycaon's sons.
  But Eumelus and some others say that Lycaon had also a daughter Callisto; ² though Hesiod says she was one of the nymphs, Asius that she was a daughter of Nycteus, and Pherecydes that she was a daughter of Ceteus. ³ She was a companion of Artemis in the chase, wore the same garb, and swore to her to remain a maid. Now Zeus loved her and, having assumed the likeness, as some say, of Artemis, or, as others say, of Apollo, he shared her bed against her will, and wishing to escape the notice of Hera, he turned her into a bear. But Hera persuaded Artemis to shoot her down as a wild beast. Some say, however, that Artemis shot her down because she did not keep her maidenhood. When Callisto perished, Zeus snatched the babe, named it Arcas, and gave it to Maia to bring up in Arcadia; and Callisto he turned into a star and called it the Bear.