Stub entry. Mortal king of Tegea in Arcadia; killer of Hyllus son of Heracles in single combat at the Isthmus of Corinth — the defeat that delayed the Heraclidae return-to-the-Peloponnese for three generations. Per Herodotus, the Tegean privilege of holding one wing of the Greek battle-line at Plataea was traced to Echemus' victory over Hyllus.