Pop singer-turned politician Sonny Bono, now mayor of Palm Springs, says students are welcome to spend the spring break in this desert resort - if they behave themselves.

Palm Springs, a resort of golf courses, swimming pools and 170 hotels, attracts thousands of students from Western states every spring, much as Fort Lauderdale, Fla., draws students from the East and Midwest.But in past years student activities in Palm Springs have turned into near-riots. In 1986, hundreds were arrested in a melee which erupted when female students bared their breasts on the streets.

Bono, who formed the hit duet "Sonny and Cher" with his then wife in the 1960s, and his fellow city councilors have decided that enough is enough.

So as of Friday tiny G-string bikinis are banned, along with the practice of male students baring their buttocks and "mooning" from cars. Poolside drinking after 11 p.m. is also out under new laws passed Wednesday.

"The new laws are not designed to stop the students having fun. But when they disrupt the lives of the citizens, certain measures have to be taken," a city council spokeswoman said.

The town, normally a haven for wealthy tourists and the elderly, experiences gridlock as students cruise the streets in cars and on motorcycles. If streets become clogged this year, police have orders to seal them off.

Fines for breaking the new laws range from $15 to $50 plus an "administrative fee" of up to $500 to pay for the police time involved in making arrests.