X-ray emission quantities as functions of stellar mass for 16, 011 stellar members of the MYStIX/SFiNCs regions. The stars are color coded according to their evolutionary status in the Hertzsprung-Russell diagram: stars on the Hayashi track (teal), Henyey track (orange), and ZAMS or beyond (blue). The black curves are spline fits to the 25%, 50%, and 75% quartiles of the X-ray distribution. In the first panel, the straight lines are regression fits from (COUP; Preibisch et al. 2005) (blue) and (XEST; Telleschi et al. 2007) (red) surveys.