Spitzer/IRAC color–color diagram for Collinder 69 for all X-ray sources with masses in the mass range 0.3–1.2 M_⊙. Solid circles – blue – represent probable members identified in the XMM-Newton survey. The large, dotted circle (in black) represent one of the two objects with excess at 24 micron (the second one has no IRAC data). Previously known members from Dolan & Mathieu (1999), Barrado y Navascués et al. (2007) and Morales-Calderón (2008) within the XMM-Newton field-of-view and with no X-ray detections are included with plus – red – symbols.