SFD98 reddening images of the six selected areas: a) SA 147; b) SA 148; c) SA 149; d) SA 170; e) SA 171; and f) SA 173. The lines-of-sight for which colour excesses have been estimated are overlaid upon the images. The sizes of the symbols scale with the estimated value of E(b − y) according to the scale shown in the upper corner inset, the negative colour excesses being assumed to be null. The stellar sample was subdivided into three ranges of distances: d ≤ 200 pc (open circle), 200 < d ≤ 400 pc (filled upper half circle), and d > 400 pc (filled circle). (A colour version of this figure is available in the online journal.)