Stellar masses (in M_⊙) of the lens galaxies as a function of redshift (spectroscopic when available, photometric otherwise). Black crosses: stellar masses inferred using the method described in Bundy et al. (2006). Grey stars: stellar masses inferred for the IRAC sources in Ilbert et al. (2010). Black and grey lines: the respective least-square fits, with a slope of  +0.8 ± 0.3 (black line) and  +0.7 ± 0.3 (grey line).