A tourist from Los Angeles suffered severe head injury after she had been struck by a scooter in Manhattan on Friday — through a night of mayhem on the streets that left two boys together with significant injuries if they were struck by automobiles in different incidents in Queens, police said.

The 65-year-old girl in town by LA was crossing West 64th Street at Amsterdam Avenue at about 7:30 p.m. every time a guy on a black and red scooter collapsed in her and then fled the scene, authorities said.

She had been taken to St. Luke’s Hospital where she had been listed as seriously hurt, with severe head injury. Authorities are searching for the hit-and-run defendant, the NYPD said.

Afterwards in Forest Hills, a 10-year-old boy had been crossing 110th Street in Jewel Avenue a bit before 9:30 p.m., when he was hit by a Honda CRV, authorities said.

The motorist, a 20-year-old guy, remained on the scene. The child has been taken to Columbia Presbyterian with severe head injury, where he’s in critical condition, authorities said.

The boy had been walking in the crosswalk, according to detectives, however it’s uncertain when he’d the right-of-way.

Then at about 10 pm at College Point, a 16-year-old on a bike was struck with a shout motorist on College Point Avenue, authorities said.

The defendant fled 15th Street at College Point at a Nissan with a busted windshield, and has been hunted by detectives, cops said.

The teenager was hospitalized with a serious head injury, officials said.

The person was taken to Bellevue Hospital with head injury after the single-vehicle accident.