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We present ultraviolet (UV) and optical photometry of 26 Type Ia supernovae(SNe~Ia) observed from March 2005 to March 2008 with the NASA {\it Swift}Ultraviolet and Optical Telescope (UVOT). The dataset consists of 2133individual observations, making it by far the most complete study of the UVemission from SNe~Ia to date. Grouping the SNe into three subclasses as derivedfrom optical observations, we investigate the evolution of the colors of theseSNe, finding a high degree of homogeneity within the normal subclass, butdramatic differences between that group and the subluminous and SN 2002cx-likegroups. For the normal events, the redder UV filters on UVOT ($u$, $uvw1$) showmore homogeneity than do the bluer UV filters ($uvm2$, $uvw2$). Searching forpurely UV characteristics to determine existing optically based groupings, wefind the peak width to be a poor discriminant, but we do see a variation in thetime delay between peak emission and the late, flat phase of the light curves.The UV light curves peak a few days before the $B$ band for most subclasses (aswas previously reported by Jha et al. 2006a), although the SN 2002cx-likeobjects peak at a very early epoch in the UV. That group also features thebluest emission observed among SNe~Ia. As the observational campaign isongoing, we discuss the critical times to observe, as determined by this study,in order to maximize the scientific output of future observations.

Near-Ultraviolet Properties of a Large Sample of Type Ia Supernovae as Observed with the Swift UVOT