Upper panel: DSS-R image of RCW 78. The cross marks the position of the WR star. The box encloses the two star-forming regions analyzed in this paper. Bottom panel: the two star-forming regions at 60 μm (IRAS data). The grayscale goes from 200 to 500 MJy sr^-1, and the contour lines are from 240 to 300 MJy sr^-1 in steps of 20 MJy sr^-1, and from 350 to 500 MJy sr^-1 in steps of 50 MJy sr^-1. Regions B and C are indicated. The different symbols mark the location of candidate YSOs identified in Sect. 6: IRAS (star), CHII (triangle), 2MASS sources (crosses), and Spitzer sources (filled circles).