Source  –  A hirsute perv flew under the radar, until his victim recognized him nearly a month later — and snapped this photo, police said.

Police are now searching for the man who they say stared down a woman while he exposed himself on November 16.

The bearded stranger’s pants were already unzipped when he sat near his 31-year-old victim on a northbound R train just after 7:30 a.m., police said.

Without saying a word, he then showed her his penis.

When the train pulled into the Pacific Street station, the man stood up, zipped up and sauntered off the train.

The incident went unreported until almost a month later on December 12, when the woman spotted the man at the Pacific Street station and took photos on her cell phone, cops said.

Police describe the man as approximately in his 30s, 150 to 160 lbs with a beard, and believe him to frequent the Pacific Street subway station.