Only in America would you find an outfit like Tucson, Ariz., quintet the Mollys. The main ingredients of their multi-ethnic musical stew are Anglo-Celtic and Mexican-American roots, with sprinkles of country, blues, rock ‘n’ roll, and even polka, spicing up the arrangements as appropriate. So at times they sound more like Los Lobos with an Irish accent and other times like the Pogues with a hint of Tex-Mex. But on their latest recording, Moon Over the Interstate, there’s even a cut that sounds like a collision between rock ‘n’ roll and old Appalachian mountain music—”Up Spoke the Baby.” And if you ever thought there might be a connection between Anglo-Celtic and Mexican folk traditions, ponder “La Llorona,” a song about a ghost who haunts Southwestern riverbeds, “looking for the bones of her drowned children,” that’s uncannily similar to the Irish myth of the banshee. The Anglo-Celtic/Tex-Mex rockin’ and reelin’ begins tonight at 9 p.m. at Iota, 2832 Wilson Blvd., Arlington. $7. (703) 522-8340. (Ken Roseman)