Histograms for different samples (and subsamples) described in Sect. 3 and identified with different techniques: optical, mid-infrared, and X-rays. The vertical dotted and long-dashed – magenta – segments locate the detection limit of each survey for cluster members. In these three subpanels – a top, middle and bottom, solid – black – lines correspond to the whole sample analyzed in each subpanel; dotted – gray – lines are used for subsamples spatially included in the XMM-Newton field-of-view, whereas dashed – red – lines describe the data with X-ray detections. Subpanel at the top – Probable and possible members from Barrado y Navascués et al. (2004b) and Barrado y Navascués et al. (2007), with an initial selection based on optical photometry. The less massive objects detected in the XMM-Newton data are LOri-CFHT-090 and LOri-CFHT-098, with  ~0.12 M_⊙. Subpanel in the middle – Members listed by Dolan & Mathieu (1999), originally selected from optical photometry (including narrow-band Hα – i.e., active stars or with accretion), and confirmed based on high-resolution spectroscopy. The thick dotted long-dashed – silver – histogram includes members in common with Barrado y Navascués et al. (2004b). The completeness limits correspond to the whole photometric survey described in Dolan & Mathieu (1999) and Dolan & Mathieu (2002) –0.35 and 0.22 M_⊙, respectively. Subpanel at the bottom – New members from Morales-Calderón (2008), composed by Class II sources (Classical TTauri stars and few members with transition disks). Initial selection based on mid-IR data from Spitzer.