ID This Caterpillar Eating Our Ixora?

[Greenside]

A big area of our Ixora hedge is infested with these which are now starting to emerge from little bundles of stuck together branch tips.  They ate a lot of the leaves before they got to this stage...  Some kind of butterfly, I assume but I can't find a picture of one to match.  Any ideas?

[cooked]

I did see a butterfly (or maybe moth) one year, it was a small, uninteresting beast. I keep our Ixora inspected and I'm afraid I spray with a systemic as soon as I see signs of infestation. Repeated two times as the eggs can't be got at. They seem to reappear at the same place so dormant eggs is the problem.

Nice fotos btw