What is compared to a "newly formed Sporting and Amusement Club" in this analogy from "May Day" by F. Scott Fitzgerald?
Down Sixth Avenue swept the procession, joined here and there by soldiers and marines, and now and then by civilians, who came up with the inevitable cry that they were just out of the army themselves, as if presenting it as a card of admission to a newly formed Sporting and Amusement Club.
Sixth Avenue
an admission card
the national guard
the veterans' group