Like so many 30-something bachelors, the heroes in the Milwaukee Repertory Theatre's latest production, The Bachelors, refuse to acknowledge the responsibilities of adulthood. Instead, they spend their days hanging out in a college-like apartment in Madison, WI, at least until they encounter a mysterious delivery girl who may be the reincarnation of a woman they both wronged in a previous life. The musical comedy, which continues its limited, two-week run tonight with a 7:30 p.m. production at the Marcus Center, is a thematic successor to two popular Rep productions, Guys on Ice and Lumberjacks in Love.