Leaf mine on lettuce.
No interactions present.
Not many contenders here: the most likely is Chromatomyia 'atricornis' - follow up on the Leaf Miners web site for the complexities of this "species"
As Robert suggests, see:
Entomologist and biological recorder
Not alot of help here, but its a good guide.
Before posting my own I visited every post of Chromatomyia 'atricornis' to see if I could learn more - I did. But like every good iSpotter I have returned to agree where possible.
Now, British records of syngenesiae, horticola or 'atricornis' on hosts other than Asteraceae in Britain, are assumed to represent horticola. is from http://www.ukflymines.co.uk/Flies/Chromatomyia_syngenesiae.php.
I may return then to add another ID. In the meantime, however Martin, I have agreed - so now you owe me a response to my Admin pleas - PLEASE.
So now why not look at mine http://www.ispotnature.org/node/740413
Lat/Lng: 52.7, 0.3
OS grid ref: TF5820