Distribution of the subdwarfs from the Savcheva et al. (2014) catalog in the [CaH1, TiO5] index diagram and histogram of their proper motions. The subdwarfs were selected by a [CaH2+CaH3]–TiO5 relation defined in Lépine et al. (2007) from SDSS DR7. The black curve on the left diagram is the original subdwarf selection criterion, i.e., the CaH1–TiO5 relation defined in Gizis (1997) and abandoned by Lépine et al. (2007). There are 1447 targets (red dots as group I) in this “subdwarf” sample that do not fulfilling the CaH1–TiO5 relation, which thus might be misclassified M dwarfs. The other ones, which could be considered as reliable subdwarfs, are figured as blue dots (group II). The right panel shows that most group I stars do not exhibit large proper motions.