Larry Donovan is a passenger conductor on the railroad and sort of professional ladies' man. Ántonia ends up completely infatuated with him, and so he takes advantage of her. Larry asks her to marry him, and then uses up her money and gets her pregnant before abandoning her. Cather does spend about a paragraph describing him after Jim learns of what he's done to Ántonia. We learn that Larry is an entirely unsympathetic character: apparently he complains a lot, uses women, and doesn't get along with men. We get the sense that Jim is right to dislike this guy. The fact that Jim knows he's bad news from the start is another testament to Jim's emotional sensitivity.