You use the semicolon with an independent clause when you join two of the independent clauses in a sentence without using a conjunction. So basically the semicolon replaces the conjunction when you're combining two independent clauses.
Answer:
The tone of the poem changes along the lines "The teeming autumn, big with rich increases, bearing the wanton burden of the prime, like widow'd wombs after their lord's decease"
Explanation:
The poem has a tone of melancholy and sadness, but the lines "The teeming autumn, big with rich increases, bearing the wanton burden of the prime, like widow'd wombs after their lord's decease" cause a change of tone. This is because these lines talk about abundance, hope that provides a certain comfort to the reader, but quickly the tone returns to being melancholy, removing this comfort previously achieved.
I think it would actually be Man vs. man, or person vs. person. The myth is about Atalanta's struggles with Hippomenes; she's a young woman, he's a clever man. He creates a situation that tricks her, or puts her into the conflict, so it'd be strictly him that she's got the conflict with. Not nature, society, or supernatural.