Symbolism, Imagery, Allegory
Prince Fabrizio is thrown off his game when he first learns that Don Calogero, the mayor of Donnafugata, has become even wealthier than him. He knew that the day would come when "self-made men" would start becoming more powerful than old world aristocrats, but he has trouble coming up against it face-to-face.
He's even humiliated when he learns that Don Calogero is going to visit him wearing a "suit with tails." A suit with tails symbolizes wealth and status. Fabrizio can't believe that some local nobody is going to waltz into his house wearing fancy clothes like this just because he's made a few bucks in his time. We hear about Fabrizio's concern directly when the book says,
Now, with his sensibility to presages and symbols, he saw revolution in that white tie and two black tails moving at this moment up the stairs of his own home. Not only was he, the Prince, no longer the major landowner in Donnafugata, but he now found himself forced to receive, when in afternoon dress himself, a guest appearing in evening clothes. (2.65)
Fabrizio has heard throughout this book that a revolution is happening in the streets, but it's not until he sees a man he considers beneath him wearing a suit with tails that he truly feels the impact of social change.
In the end, he's happy to find that Calogero's coat is horrifically tailored, which reassures him that people with new money will never be able to have the sense of style that it takes generations of wealth to produce. As the book tells us, "Though perfectly adequate as a political demonstration, it was obvious that, as tailoring, Don Calogero's tailcoat was a disastrous failure" (2.66). Failure or not, though, Fabrizio can see the writing on the wall. The future belongs to men like Calogero, and not him.