Two Camp Springs teen-agers were arrested early yesterday in connection with two robberies and an unrelated assault that left a Chevy Chase student with 25 stitches in his head.

Police said the first incident occured about 1:15 a.m. on the Clavert Street Bridge in Northwest Washington when a Woodley Park woman was returning home after escorting some children to their home after a party.

A souped-up 1966 Dodge pulled up beside the woman and one of its passengers shouted, "Drop the purse." The woman refused and when one of the youths jumped out of the car, she began running along Connecticut Avenue.

A Maryland cabdriver pulled up beside her, she jumped in and they drove off.

The Dodge then followed the cab for a few blocks, its passengers yelling obscenities, and then sped off.

The second incident came at 1:45 a.m. at Military Road and Nebraska Avenue NW. One youth, said Detective Vincent Tolson, pulled what appeared to be a gun on a 20-year-old law student, took $90 and ordered her to, "run and not look back."

The third attack involved a 21-year-old Chevy Chase man who was riding his bicycle south on Neveda Avenue NW to pick up some keys he had left at a playground five blocks from his home, police said.

According to the student, "They just sort of appeared from between two parked cars." They hit me with the old 'Give me your money' line, and then they hit me with the iron club."

He was struck twice on the head and then ran down Neveda Avenue with his assailants in pursuit for about two blocks. The man, a junior at the University of Virginia, required 25 stitches on his head.

Police arrested two youths after issuing an all-points bulletin for the blue hotrod. Doug Adams, 18, of 6102 Hope Dr., Camp Springs, and a 17-year-old juvenile were charged with armed robbery, attempted robbery and assault with intent to rob.