Leaf Mines on Dock

From last summer: a leaf mine on a dock leaf (Rumex sp).  The yellowish larvae can be seen in the lower right. The black particles are are waste matter that the larvae have excreted.  The larvae are probably those of a species of fly, maybe a Pegomya sp (Diptera: Anthomyiidae).

This is the full dock plant:

I took one of the mined leaves home with me, put it in a plastic tub and left it for a few days to see what developed. 

After about a week I found the following larva in the tub:

And also several puparia like this:

Then I forgot all about the tub and didn't look again at it until several months later.  What I found then will be the subject of tomorrow's post.

First photo and specimens taken in Whiteknights Park, Reading, UK, on 2013-06-23.