2MASS J − H vs. H − K_s diagram of Galactic evolved stars. This diagram does not allow for a photometric classification. SR variables are taken from Alard et al. (2001), large amplitude variables (LAVs) stars from Glass et al. (2001), and AGBs with SiO maser emission from Messineo et al. (2002). OH/IR stars are from Sevenster (2002). The selection of RSGs is described into the text. WR stars are from van der Hucht (2001); Messineo et al. (2009, 2011), LBVs are from Clark et al. (2005); Messineo et al. (2011); Gvaramadze et al. (2010); Mauerhan et al. (2010, 2011). The continuous line near the bottom left corner is the locus of dwarf stars (Koornneef 1983), two dashed lines mark the traces of an O9 (lower) and an M5 (upper) star with increasing interstellar extinction. A reddening vector for A_Ks = 1 mag is also shown (Messineo et al. 2005). Typical errors are within 0.05 mag in both axis.