Location of the pulsating Am stars in the HR diagram. The circles are pulsating Am stars, with the filled circles indicating those with spectral classification noted as δ Del. The crosses are the Fm δ Del stars which were not found to pulsate. The solid lines indicate the location of the ZAMS and the fundamental radial mode red and blue edges of the instability strip (Dupret et al. 2005). The large cross indicates the typical uncertainties in log T_eff and log L.