Comparison between non-rotating Galactic Z Bonn evolutionary tracks on the MS published by Brott et al. (2011, black dashed), and our MESA models calculated with a similar setup (colored lines). A step overshoot parameter, α_ov = 0.335, was used. Stars above 40 M_⊙ are still on the main sequence at rather low effective temperatures. The lack of hooks at higher masses is due to envelope inflation (N. Langer, priv. comm.), treated similarly in STERN and MESA.