Arthur J. Haggerty, who pioneered David Letterman’s Stupid Pet Tricks and played Mr. Clean at trade shows, died July 3 in West Palm Beach, Fla., of cancer. He was 74.Services will be held Aug. 8 at 11 a.m. at Our Lady of Peace Church, 237 E. 62nd St., New York. Born in the Bronx, he was a commanding officer of the K9 Corps in the U.S. Army. After the Korean War, he founded Captain Haggerty’s School for Dogs in New York, which trained dogs for celebrities including Brooke Shields, Liza Minnelli and Hugh Hefner. His theatrical dog agency trained and supplied dogs for “All My Children,” “The Guiding Light,” the Broadway production of “Annie” and many commercials. He appeared on “The David Letterman Show” 26 times with his Stupid Pet Tricks act. While supplying dogs for Burt Reynolds starrer “Shamus,” the tall, imposing bald trainer was selected to play a villain. He went on to appear in films including “Annie Hall,” “Married to the Mob” and “Honeymoon in Vegas.” He is survived by a daughter, a brother and two grandchildren. Donations may be made to the AKC Canine Health Foundation, Take the Lead or the Hospice of Palm Beach County.