$\sim 10^{11}\,M_\odot$ galaxy in the LOSS sample. Assuming $Z_g$ and $t_g$ to be separable, we use the 16/84% ranges in log $Z_g$ from @Gallazzi:2005df to again weight the galaxy distribution at fixed mass and introduce an overall term to account for the effect of metallicity in Eq. (\[eq:rate\]), either $f_{0.85}(Z)$ or $f_{0.70}(Z)$.

![The total masses of known WD-WD systems along with their calculated merger times due to gravitational wave losses. Shown are the three systems from the collection in @Nelemans:2005qb in which both WDs have masses exceeding 0.5 $M_\odot$: two with firm masses ([*circles*]{}) and one with only a lower limit on the mass of the secondary ([*triangles*]{}). Assuming these to have all resulted from stars with $Z\sim0.02$, we show the “expected” total masses for a range of metallicities (as labeled) using the final masses derived in @Umeda:1998ij. The resulting merger times assume initial orbital separations as presently inferred for each. \[masses\]](masstime){width="3.35in"}

The specific SN Ia rates resulting from using the two metallicity scalings are shown in Fig. \[Iarate\]. For the $f_{0.85}$ model, $\phi_* = 1.1\times 10^{-3}\,$$(10^{10}\,M_\odot)^{-1}\,$yr$^{-1}$ with $\Delta t_{\rm Gyr}^{-0.8}$ (dashed line), while the $f_{0.70}$ model has $\phi_* = 1.3\times 10^{-3}\,(10^{10}\,M_\odot)^{-1}\,$yr$^{-1}$ and $\Delta t_{\rm Gyr}^{-0.9}$ (dotted line). After accounting 