The average sizes of amorphous grains plotted versus the accretion rate of the central stars. The grain sizes are derived in the warmer region of the IRS spectra. The filled symbols show the CTTSs, and the open symbols represent the WTTSs. The targets in MBM 12 are shown as circles, in η Cha as squares, and in the Coronet cluster as triangles. The diamonds show the targets from Olofsson et al. (2010). The pentagram marks object ID#10 in ϵ Cha. The thick dashed lines are the fit to the relation between the accretion rates and the grain sizes for Ṁ_acc > 10^-9 M_⊙ yr^-1.