An alleged serial bank robber nicknamed by authorities the "Straw Hat Bandit" struck again Saturday in Montgomery County, authorities said.

Around 10:10 a.m., the man - who concealed his appearance with a tan hat and a makeshift mask of fabric with eyeholes - robbed the PNC bank at 1216 Welsh Rd. in North Wales, the FBI said in a statement.

After brandishing a black semiautomatic handgun and ordering customers to the floor, he demanded money from tellers, then fled on foot after receiving an undisclosed amount of cash.

The Straw Hat Bandit - nicknamed as such for a previous disguise - is believed to be responsible for 10 other bank robberies in Montgomery and Bucks Counties over the last four years.

The FBI and police are seeking the public's help in finding the man. He is white, believed to be in his 50s or older, and is about 6 feet tall with a muscular to stocky build.

In the latest holdup, he was wearing a dark-colored suit jacket over a light-colored dress shirt and navy tie, dark-colored pants and shoes, and white rubber gloves.

Anyone with information is asked to call the FBI at 215-418-4000 or the Montgomery Township Police Department at 215-362-2301. Tipsters can remain anonymous.

There may be a reward from law enforcement for the man's arrest, and PNC also is offering a $10,000 reward for information leading to his arrest and conviction, the FBI said.

Almost exactly a year ago - on July 3, 2015 - the man allegedly robbed the Wells Fargo Bank at 1675 Limekiln Pike in Dresher.

He is also believed to have robbed a Colonial American Bank in Horsham on June 8, 2012; a First Federal Bank in Wrightstown on Sept. 28, 2012; a Wells Fargo Bank in Yardley on Jan. 18, 2013; a PNC bank in Ambler on March 30, 2013; and a Harleysville Savings Bank in Royersford on May 24, 2013.

And he is suspected to be behind the robberies of a Univest bank in Schwenksville on May 24, 2013; a Wells Fargo Bank in Ambler on Aug. 30, 2013; a First Priority Bank in Blue Bell on Jan. 2, 2014; and a Wells Fargo Bank in Plymouth Meeting on Jan. 6, 2015.