Low-lying spectra of ' 'Dy, ' Er, and ' 'Yb are studied in the framework of the pseudo SU (3) model allowing natural parity neutrons alone to be active. Various interband and intraband B(E2) values are predicted and compared with experimental results and other model calculations. The agreement is quite reasonable. We predict a different level structure for the 2+ quasirotational band in ' 'Dy and 3+ quasirotational band in ' Yb. The present calculation shows that the enlargement of the natural parity neutron space will improve the predictions considerably. lÑ UCLEAR STRUCTURE 4Dy 6 Er ' Yb, Pseudo SU(3) model, only natural parity neutrons, Q. Q Interaction, calculated levels, B(E2), ' Er-I~, compared with experiment and other models.