Cops found a missing 8-month-old girl in the back of a livery cab with her biological mother after the Queens woman snatched the baby from her foster mother, who had taken her to a hospital for a doctor visit, authorities said.

Leila Rajnarie, 40, was nabbed last night about eight hours after she had suddenly bolted from Queens General Hospital with the child in her arms.

Rajnarie does not have custody of her daughter.