Cobweb On Bush

[Mccracker]

On a bush near my nearest bus stop it is totally covered with a cobweb like it is enveloped in it ,it is under a tree there are hundreds of black caterpiller type bugs about a centimetre long all over the cobweb.Any idea what they are
Many thanx in advance

[FredPuli43]

These are the webs created by the ermine moth caterpillar. The caterpillars are present in great numbers on the trees and the web is for protection . They will pupate, emerge as moths and be gone within weeks.

[Mccracker]

Thanx FredPuli43 they are all over the place down there

[Chipchopper]

Any idea of what kind of bush they are on ?
The reason I ask is because some species of moth or butterfly have specific food plants, this may help determine and identify what they are.