Nairnshire,
United Kingdom 
Elder trees covered in tough gauze type webs. Black something inside this gauze and the leaves are all disappearing
28 Jun, 2010
Answers
Probably Ermine Moth larvae. They seem particularly widespread this year.
28 Jun, 2010
Previous question
There are a couple of species of Moth that have almost colonial larvae and build huge webbing to protect themselves from bird and parasatoid insect predation. It does sound like one of these.
28 Jun, 2010