By using tunneling microscopy and spectroscopy techniques we investigated the atomic and local electronic structure of the rare-earth metals Gd and Tb onW(110) in the submonolayer coverage regime. Both elements arrange themselves in similar superstructures on top of theW(110) surface. LEED investigations and topographical images obtained with a tunneling microscope show virtually no difference between the Gd and the Tb superstructures. Only investigation by tunneling spectroscopy reveals small but systematic differences in the electronic structure.