Identified Class I YSOs in the field of bipolar nebulae, using two indicators. The underlying diagram is that ofthe region G316.80–00.05 (Fig. B.9), although the diagram of any other region could have been used. The colours give the nature of these sources according to their [8]–[24] colours. Green, blue, and black circles identify Class I, flat-spectrum, and Class II YSOs, respectively. Black “X” sources are for probable evolved stars. Small red dots are for sources of unknown nature because their 24 μm magnitude is unknown. The extinction law is that of Indebetouw et al. (2005).