On the same clump of knapweed as the Urophora jaceana from ten days earlier, but here the pattern on the wings is slightly different so I think this one is probably Urophora stylata (Diptera: Tephritidae).
Photos taken in the Wilderness, Whiteknights Park, Reading University grounds, Reading, UK, on 2010-06-25.
Last year I saw one of these flies on yarrow (Achillea millefolium) but, at the time, conjectured that it had just been blown off some nearby thistles. Well, the above fly was in the same area so it seems more likely that last year's fly was blown off the knapweed onto the yarrow.
A few weeks ago I saw another species of gall fly, Urophora jaceana, on knapweed, but that was over in the Wilderness, quite a way away.
Photo taken in Whiteknights Park, Reading University grounds, Reading, UK, on 2010-07-04.
I was walking up from the town with my shopping last Saturday morning when I noticed this rather splendid moth on the path. I bent down and took it up on my finger, where it stayed all the rest of the way home. I set it down on our living room window where I took a few photos before releasing it through the window.
Photos taken in Reading, UK, on 2010-07-03.