Bob Hope traded girlfriends with Bing Crosby and kept beautiful women in apartments near his home so he could visit them on his midnight strolls, Groucho Marx's son claims in an unauthorized biography.

A Hope spokesman described "The Secret Life of Bob Hope" by Arthur Marx as "just a lot of old stuff, nothing new."Marx, whose book is being published this month, said the 90-year-old entertainer had an active extramarital sex life.

"It's believed Bob Hope has made love to more beautiful women than Errol Flynn, my Uncle Chico and Bing Crosby combined," Marx wrote.

Stories of Hope's sexual activities have circulated in Hollywood for decades, some privately told by the comedian himself. An occasional magazine article touched on them, but Hope always brushed aside the reports publicly.

Marx's book is the first to suggest such activities. Among its allegations as excerpted in this week's supermarket tabloid Star:

- "Hope and Crosby used to trade girlfriends - the bimbo, one-night-stand types so common on studio lots. If Crosby found a girl he thought was particularly good in bed, he'd promptly introduce her to Hope, and vice versa."

- Hope once told an agent about an appearance: "The money's OK. Just be sure to get me the best hotel suite, the best masseur and the best hooker in town."

- Hope kept beautiful women in apartments near his suburban Toluca Lake home and visited them during his midnight strolls.

- Hope often chose beauties for his overseas tours from those he expected would bed with him.

- Dolores Hope, the comedian's wife for 59 years, was aware of her husband's transgressions but would never divorce him because of her Roman Catholic religion.

"I think Bob has done a lot of good things in the world," Marx said in a telephone interview Wednesday. "I'm not throwing rocks; I'm just telling the story of his life. If a few rocks come at him, that's the way he lived."

Asked for a reply, Hope publicist Ward Grant said: "We're not dignifying the book with any comment. I always deplore those who make a living off the degradation of others. I hope (Marx) makes a lot of money off the book so he can buy his own damned life."

Marx, 72, has written a book about his father, "Life with Groucho" ("he threatened to sue me"), as well as unauthorized biographies of Red Skelton, Dean Martin and Jerry Lewis, Mickey Rooney and Samuel Goldwyn.