The San Mateo County Arts Commission told sculptor Bill Iaculla to add a fig leaf to his life-size statue of a male sleepwalker. The work, suggested by the Italian opera "La Sonnambula," went on display last week as part of an exhibit at San Mateo County headquarters. But an hour after it was set up, an anonymous critic covered the genital area with brown wrapping paper. A short time later, Iaculla was advised by the commission that his statue was too graphic. "They said they were going to go out and buy a swimsuit to put on it," the 52-year-old artist said. Instead, Iaculla fashioned a fig leaf out of paper, glued it to a loincloth and set it in place. "In Europe, male and female nudes are acceptable," Iaculla grumbled. "Here in America, what are we trying to hide?"