Surface layer of cocoon is called as

Solution(By Examveda Team)

Surface layer of cocoon is called as Floss.
Floss silk is the filaments from the soft, internal covering of a silkworm cocoon, and in particular from the places where the cocoon is not damaged by the caterpillar. Floss silk is normally classed as a continuous filament. The silk is unravelled off the cocoon, dyed and then made into hanks.
Silk fibroin (SF) is a crystalline protein-based fiber surrounded by layers of the gum sericin protein, which reinforces the cocoon structure, where it is very suitable for the subsequent development and metamorphosis of the matured larvae to pupae.