Effective temperature towards the end of the main sequence (Y_c > 0.8) and core He-burning for non-rotating (solid curves) and rotating (dashed curves) Ledoux (red) and Schwarzschild (blue) models. Upper row: masses between 7 and 15 M_⊙. Lower row: masses between 20 and 40 M_⊙. In each row, the vertical axes in all panels share the same limits, which are indicated in the leftmost panels.