I did a post on Twig Wilter Bugs about 18 months or so ago after finding a number of them in my garden. It seems that they appear seasonally as a little while back I had a whole "invasion" of them on a creeper plant in my back yard. They live off the sap of the plants causing the plants to wilt. Hence the name.
Seeing that they produce a foul-smelling secretion as a defence I decided to keep my distance, although they kept on turning around and moving off when I got too close with my camera.