A hit-and-run driver fatally struck a female pedestrian early Saturday morning Queens, authorities said.

Betty Jean DiBiasio, 21, was crossing Ditmars Boulevard near 19th Street in Astoria around 2:30 a.m. when she was mowed down by a driver heading west on Ditmars, cops said.

Police said the motorist sped off, leaving DiBiasio lying in the road with a severe head injury.

First responders rushed her to Elmhurst Hospital Center, where she succumbed to her wounds.

Investigators scoured the intersection for witnesses and surveillance video of the crash Saturday morning.

A police source said a preliminary canvass indicated the vehicle may have been a silver sedan.