Urophora, indeed. Most likely is U. jaceana, but U. cuspidata and U. solstitialis are similar in general built and wing pattern. The only reliable way to separate them is the tip of the ovipositor (R.E.S. Handbook work, sorry). Blowing up the image leads me to believe that U. jaceana is the best match, which is very convenient as it is also by far the commonest of the three species. Without details of location and (possible) host plant there is little more I can add.