“It’s silliness; it just got insane,” Ms. Higgins said. “This is what your tax dollars are paying for. The agents are coming down here on vacation, going to bars and taking pictures of cats.”

At one point, the agency recommended a night watchman for the cats. It later threatened to confiscate them. A federal judge in the case even led an impromptu field trip to the museum; federal marshals cleared a path of tourists for the suit-wearing contingent. The legal back-and-forth filled six boxes.

The rumpus has caused no consternation in the lives of the Hemingway cats (and there is a question as to whether Hemingway ever even owned a six-toed cat, but that is another story).

One recent afternoon, a furry Lionel Barrymore nibbled on kibble then hopped off a rock and sauntered away. Hairy Truman sprawled languorously on the patio table, soaking up rubs. And Francis, named for a 2004 hurricane that hit Key West, nestled comfortably on Papa’s pillow as guests oohed and aahed.

Some took as much delight in the Hemingway cats as they did in Hemingway lore.

“Hemingway gets you here the first time,” said Elizabeth Zettler, 28, who visits every year from Jacksonville, Fla., as she zoomed her lens in tight on Francis. “But the cats keep us coming back.”