The NYPD has busted a serial subway perv who is a “poster child” for prolific transit offenders — renewing the call to ban such recidivists for life.

Cops nabbed James Hunt — one of the “Dirty Dozen” repeat offenders who has scores of arrests for subway sex crimes — at the 42nd Street Bryant Park station Thursday for groping a 13-year-old girl who was buying a MetroCard, officials said.

Hunt, who allegedly likes to masturbate in front of commuters while sucking his thumb, has racked up at least 78 arrests, including 32 for transit sex crimes, according to sources.

Sgt. Christopher O’Connell, commanding officer of the Transit Special Victims Squad, called Hunt the “poster child” for serial subway crimes and said he should be barred from the trains for life.

“I believe he should be banned from the subway,” he said. “Regular people get up and go to work, they go to school, to doctors appointments, and he’s out there preying on people. This is all he does.”

The grimy groper was panhandling inside the entrance to the station at about 3:20 p.m. when he approached the young girl and asked for money, police said.

When the teen refused, he grabbed her arm, rubbing and kissing it while moaning.

The frightened girl wrestled out of his grasp and then ran for the nearby transit officers, cops said.

He was arrested and charged with forcible touching, public lewdness and acting in a manner injurious to a child.

O’Connell, who has been with the NYPD 17 years, reiterated the need for a lifetime ban for offenders like Hunt, who leave officers frustrated with the lack of any permanent solution for keeping the pervs from riding the rails.

“He’s a menace, just by his record alone. It’s a terrible thing, and it shouldn’t be OK,” he said.

His squad keeps tabs on the transit creeps, tracking their movements through the subway and monitoring Crime Stoppers tips from riders.

“The public has been a great, great help in the majority of our cases,” he said. “It’s through media, through The Post, through the Instagram page — all of that has been monumental in helping us solve our cases.”

Last week the NYPD said that serial sickos who are convicted of transit crimes more than once could be banned from the MTA permanently — and Gov. Andrew Cuomo came out in support of such a ban earlier this month.

“They’re highly recidivist, all of them,’’ NYPD Chief of Detectives Dermot Shea told The Post recently. “They get over and over arrested for the same things. They ride the same train lines.”

There have been 624 sex-related subway complaints in the city so far this year — up from 609 for the same period last year, records show.