Four Stafford County, Va., teenagers, apparently coming home from school, were fatally injured yesterday afternoon when their Volkswagen Beetle skidded on a curve and crossed into the path of a school bus that was empty of passengers, state police reported.

The collision occurred about 3 p.m. on Route 643, about a mile south of North Stafford High School near Garrisonville,, a State Police spokeswoman said. The site is about 40 miles south of Washington.

The four teenagers were identified by police as James E. Thomas Jr., 18, the driver of the car; Victor Guzman, 16; Dwight M. Alexander, for whom no age was given, and Vi Do, who was described only as a ninth-grade student. Police said all lived in Stafford.

Investigators said the students' car was headed south at a speed considered too great for the curve when it went out of control on the two-lane road and skidded into the path of the northbound bus, according to police spokeswoman Lucy Caldwell.

She said the car was struck broadside on the passenger side, pushed about 30 or 40 feet and severely damaged. She said the bus was also damaged extensively.

The bus driver, Gloria Graham, 40, of Stafford, was treated at Potomac Hospital in Woodbridge and released. Authorities said she was was wearing a seat belt. Caldwell said none of those in the car was wearing a belt. Caldwell said that at the time of the crash the bus driver was apparently on her way to pick up intermediate school students after taking elementary school students home. Rescuers found three victims trapped in the car. A helicopter was called to take the fourth to Washington Hospital Center, but he apparently died on the way.