From Warhammer 40k - Lexicanum
Spinewyrms are creatures whose larvae are collected by the Blood Angels, in order to produce the taffeta used to make the Chapter's standards and ceremonial tabards. They will spare no effort to have access to the creatures and the Blood Angels have even fought wars to attain the Spinewyrms' larvae.
- 1: Codex Supplement: Blood Angels (9th Edition), pg. 7 - Heritage of Sanguinius