Bagworm Moth

This bagworm caught my attention for two reasons: 1. The bag appears to be entirely made of silk, I can't see any hint of any other collected materials. 2. This Bagworm seems to have affixed itself to the branch by a strap or belt, rather than the sticky silk pad which is, as far as I have observed, the more common method. I think I am right in saying that neither Wikipedia nor Philippine Lepidoptera mentions the exact material(s) used in attachment. Wiki calls it "the attachment substance".