Sentence:  The upshot is, we are guided by a party of shock-headed Arcadians, who are going in the direction of the excavations, and a <WSD>Megapolitan</WSD> boy who has probably an eye to gain. 
Meaning of the word marked with <WSD> tags:  Of, pertaining to, or from the ancient city of Megalopolis (now Megalopoli) in Greece.