Region of MHO 2102 and MHO 2151. Top-left: the H₂ image with MHOs and YSOs labeled; top-right: the Ks image for the same region; bottom-left: the continuum-subtracted H₂ image with MHOs labeled; bottom-right: the H₂ image with the PMs marked. The YSOs from Evans et al. (2009) are marked with white or black circles and the X-ray sources from Pillitteri et al. (2010) are labeled with red crosses. The positions of the sub-millimeter sources from Johnstone et al. (2000) are marked with green filled diamonds and the positions of the millimeter sources from Young et al. (2006) with blue filled squares. The PM vectors of MHOs are shown with arrows and the dashed lines show the errors of PA. The black arrows represent reliable PMs and the red arrows represent uncertain PMs. Source designations used are as follows: [EDJ2009] is from Evans et al. (2009), [GY92] is from Greene & Young (1992b), GSS is from Grasdalen et al. (1973), LFAM is from Leous et al. (1991), YLW is from Young et al. (1986b), BBRCG is from Barsony et al. (1989), WLY is from Wilking et al. (1989), WSB is from Wilking et al. (1987), WL is from Wilking & Lada (1983), and EM*SR is from Struve & Rudkjøbing (1949).