(KLU), where 1 KLU = $\rm 4.5 \times 10^{-19} ~ ergs ~cm^{-2} ~ s^{-1}~arcsec^{-2}$. Thus, a night integration of 5 ks corresponds to U(1032) = 3.9 KLU or a 3$\sigma$ LWRS upper limit of $\rm 1.56 \times 10^{-15} ~ ergs ~cm^{-2} 
~ s^{-1}$, assuming a filled aperture and an unresolved line width (106 $\rm km ~ s^{-1}$). This is more than two orders of magnitude below the measured F(1032) in the bright LMC remnant N49 (Blair et al. 2000b), although the line width in that case was over 400 $\VEL$.

Few of the non-detections can be attributed to short integration times (see Table 2), and the inferred upper limits on emission in O VI, at least at the observed locations, are quite small. Of course in many objects the region sampled by the $\fuse$ LWRS aperture is a tiny part of the projected surface area. A clumpy distribution of O VI emission could be present, so the absence of detected O VI does not necessarily indicate a complete absence of O VI emission from an object. For completeness, we indicate the $\fuse$ aperture positions on optical (MCELS) and X-ray images (when available) of all non-detections in Figures 19-24. Inspection of 