Where does “Εὐμολπίδης” come from?

Εὐμολπίδης (Ancient Greek) comes from Ancient Greek Εὔμολπος, from Ancient Greek εὖ, from Ancient Greek ἐΰς, from Proto-Hellenic ehu-, from Proto-Indo-European h₁su-, from Proto-Indo-European h₁wes- — good; to be cheerful, happy; to eat, to feast.

Εὐμολπίδης (Ancient Greek): a child of Eumolpus; one of the Eumolpidae; a Eumolpid