Abstract: The subject of the talk is a spinless particle in a homogeneous magnetic field whose motion is restricted to a layer with Dirichlet boundary conditions perpendicular to the field. The presence of a periodic family of point interactions causes a change of the spectrum which will contain bands in addition to the generalized Landau levels. Using the Landau-Zak transformation together with Krein's formula we are able to describe these bands and find their number in the case of a rational flux through the elementary cell.