To study the effect of nucleon number on nuclear levels of odd-mass rare-earth isotopes, enriched isotopes of Er and Yb were irradiated with protons in the ORNL 86-inch Cyclotron. After chemical separation, the decay chains leading to stable isotopes were analyzed with internal-conversion, photographic-recording, permanent-magnet spectrographs. Precise energy values as well as photometrically measured intensities of conversion lines of 8 to 1600 kev energy were obtained. Very light isotopes of Lu and Tm, each eight mass units from the mass stability line, were produced. The following activities were studied: Tm161, (~30 min), Ho161m (E3, 211 kev), Tm163 (2 hr), and Lu167 (54 min), all previously unreported, as well as Tb161, Ho161, Tm165,167, Yb167, Lu169,171,173, Hf173, and possibly Yb169m. Genetic relationships and partial level schemes for decay chains of masses 151 to 173 are shown. Where comparison is possible, excellent agreement with the predictions of Mottelson and Nilsson is obtained, particularly for the case of the various isotopes of Tb (Z=65), Ho (Z=67), and Tm (Z=69), where striking similarities in the level structure are observed.