A study of 67 E and S0 galaxies located mostly in the field and in groups reveals that at any given luminosity the UBV colors become systematically bluer as the amount of fine structure (ripples, jets of luminous matter, X-structure, and boxy isophotes) increases. Figure 1 shows the resulting correlations between the color residuals δ(U – B)e,0, δ(B – V)e,0 (calculated as deviations from the mean color–luminosity relations) and the fine structure parameter Σ. These correlations closely resemble correlations found earlier between CN, Mg2, and Hβ line strengths and the same parameter Σ in 36 ellipticals (Schweizer et al., Ap.J. Letters 364, L33, 1990). Both sets of correlations are most likely due to systematic variations in mean age, rather than mean metallicity, of the stellar populations in these early-type galaxies. We model the evolution of galaxies undergoing a major merger by convolving a single-burst model (Charlot & Bruzual, Ap.J. 367, 126, 1991) with a star formation rate that declines exponentially with a long time constant (6–10 Gyr) before the merger and with a short time constant (0.1–0.5 Gyr) afterwards. Some of the model parameters are determined from observations of two 1–2 Gyr old merger remnants. Comparisons between the observed UBV colors and the models suggest that the bluest E + S0 galaxies in our sample formed through mergers only a few billion years ago, which also explains their high amount of fine structure.