Melanippus is a 'noble' propitious name and a number of men were so called, including the lover of Comaetho, the son of Astacus and the son of Theseus and Perigune who was a famous runner. The name means 'black horse', or put another way 'he of the black steed', from meias and hippos (like Melanippe). Notice that Theseus' son was a runner, as is a horse (of any colour).