You know this Worm?

[vaca]

Hello,

I've found this little worm nesting inside one of my lettuces  >:(  It had made a little home for itself by wrapping one of the small new leaves around itself and closing it shut with some silk. And has also had a meal or two from one of the larger leafs.

Can anyone tell me what this worm is and more importantly what I can do to get rid of them?

I've also noticed that they've been at my trees in my garden as well and seem to like any new budding leaves to make a home for themselves.

Thanks,
vaca

[vaca]

[Robert_Brenchley]

Something which had gone there to pupate I'd say. It looks rather like a sawfly; what trees have you seen them on?