Below the waist, they wear studded punk-rock belts, jeans and sneakers. Above the waist, they wear Gryffindor ties, grey V-neck sweaters and round black spectacles. On stage, they introduce themselves as “Harry, Year 4” and “Harry, Year 7.”

Together they are Harry and the Potters, two brothers — Paul, 25, and Joe, 17, DeGeorge — who are on tour this summer playing songs based on and inspired by Harry Potter.

This year the Boston natives released their second album, “Voldemort Can’t Stop the Rock!” During the school year, the band plays only one or two shows a month, but this summer it will be playing at least 20 shows on both coasts and several Midwest shows, including last Tuesday’s show at the Women & Children First bookstore in Chicago.

Harry and the Potters was created when two bands scheduled to play a concert in the brothers’ shed canceled, so Joe and Paul sat down and wrote seven Potter-themed songs in an hour, quickly rehearsed them and performed them for a crowd of eight people.

Nine months later, as the fifth Harry Potter book was nearing its release date, the brothers released their eponymous first album. When “Harry Potter and the Order of the Phoenix” hit bookshelves, they started playing shows in Borders bookstores and libraries.

“We thought the juxtaposition was pretty hilarious: Libraries are nice, quiet places,” said Paul, who works in the process development group at the vaccine company Acambis. “We’re not even going to play acoustic, we’re going to play as loud as we can get away with.”

The band plays mostly free concerts, with the exception of benefits and “normal” non-library collaborations with other bands, Paul said.

Not surprisingly, the DeGeorge brothers are huge fans of J.K. Rowling’s best-selling novels.

“What really amazes me is (the Harry Potter books have) become this thing that’s crossed so many generations,” Paul said. “It gives kids a way to relate to adults in a way that they never could before.”

This fall the brothers will probably take off some time to fill out college applications: undergraduate schools for Joe and engineering graduate schools for Paul. The duo is uncertain how much further their Potter fling will take them.

“I’m not really sure what to think of it,” said Joe, a rising high school senior. “It started as a joke, but now we ended up on tour. If people like it, I guess we’ll keep doing it. I mean, I’m in a band to entertain, right?”

Lyrics excerpts by Harry and the Potters

Platform Nine and Three-Quarters:

Oh the bus don’t go to Hogwarts

You gots to take the train

Diagon Alley:

Diagon Alley is neat

For wizards it can’t be beat

It’s the place they go to get stuff

My Teacher is a Werewolf:

He’s liable to bite someone in class

That would be so bad

He’s been locked inside the Shrieking Shack

But he’s the best Dark Arts teacher we’ve had

Scene Editor Ben Rosen is a Weinberg senior.

He can be reached at [email protected].