CLOSED: What butterfly or moth could these caterpillars be from?

I found them crowded on an oak tree leaf some days ago.

grape leaf skeletonizers, what a great picture!!!!!!!!

Thanks kitten, but the problem is they are not on grape leafs but on oak leafs...

It doesn't matter what you find them on. They can eat up a storm try sprating with something like malathion for a small tree, I use products that contain permethrin or liquid sevins. It depends on how tall the tree is. Lowes or homedepot has bug sprays anything shold take them out, there not a tough kill bug.

Are they on a lot of leaves or just a few? I can't tell you what a WOW picture that is. I know for you it's not great but again, WOW!

These more likely are larvae of the buff-tip moth (Phalera bucephala ) - see http://insektenfotos.de/Phalera%20bucephala%20(Mondvogel),%20Raupengesellschaft_004.jpg
They live gregariously and feed on a number of different deciduous trees, including oaks.
See http://pbc.codehog.co.uk/bhs/pics/200506/buff-tip_27jun05_800_20.jpg for an adult moth.

YOur right, again I didn't notice the black going down, instead I thought side to side, either way an easy kill.

Thanks Suunto! But the link to the German site didn't want to open on my computer.
I found this image of the caterpillar of Phalera bucephala on the Wikipedia site but it doesn't really look like mine..

http://images.google.be/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/thumb/c/c6/Phalera_bucephala_20050909_453_part.jpg/450px-Phalera_bucephala_20050909_453_part.jpg&imgrefurl=http://commons.wikimedia.org/wiki/Image:Phalera_bucephala_20050909_453_part.jpg&h=600&w=450&sz=54&hl=nl&start=4&tbnid=9VPdmlGcOB1ASM:&tbnh=135&tbnw=101&prev=/images%3Fq%3DPhalera%2Bbucephala%26gbv%3D2%26hl%3Dnl%26sa%3DG

just get any insect liquid and spray the tree, make sure it's earlyin the day or later at night or the pesticide could burn the leaves. Also, make sure the wind isn't over 5 mph, some say 10 but play it safe. If you squirt a little dish soap in the sparyer it will help the pesticide stick better to the leaves. If you don't have a sprayer, just buy a bottle of something and set it to stream itf it's too far away and spray if it's close. When you look at the bugs look at the pattern of the black, it's going down the back. I thought it was going side to side, 2 different bugs. Never mind how bright the colors are just look at the pattern of them.Oh, once the chemical dries the kids, pets and you can go around the tree.

Thanks for the advise kitten, I know you mean well but I've never used any pesticide in my life and have no plans to ever do that as my philosophy is to live and let live... Besides that the tree is not in my garden, but in a Nature Reserve where Nature is supposed to be left intact. The tree is very healthy and can take some minor damage of caterpillars..

Well, in that case enjoy the veiw I think if the insect is not causeing too much trouble then enjoy watvhing

This caterpillar can be quite variable in appearance as it matures - http://www.rodeland.de/fotos/lepidoptera/phalera_bucephala.htm and http://farm1.static.flickr.com/22/40430853_4f8a865403.jpg?v=0

Oh, now I see! It's definitely the one. Thank you so much Suunto!