Corrected 2MASS K _s magnitude as a function of Galactic latitude for the samples from Deguchi et al. (2010; left) and our survey (right). Filled and open circles indicate SiO maser detections and nondetections, respectively. In the right panel, a data point with corrected K _s of 13.8 mag and Galactic latitude of 34° (with no SiO maser detected) is not shown, in order to visualize the distribution of the sample better.