Answer:
The trait that helps illustrate a contrast between Eumaeus and Melanthios is Xenia.
Step-by-step explanation:
The trait Xenia means hospitality. In The Odyssey, Eumaeus and Melanthios both face a situation with Odysseus where they both reacted in very opposite ways. First Eaumaeus gives shelter and offers help to Odysseus without knowing who he was, whiles Melanthios does the opposite by taking advantage of Odysseus when he believed he was a vagabond.