As the fibroin is pushed through these glands, it is coated with a gumlike substance called sericin. Before coming out of the spinneret, located at the worm’s mouth, two fibroin fibers are stuck together by the sericin.
Izdaloties no šiem dziedzeriem, fibroīns pārklājas ar līmveida vielu sericīnu, kas salīmē kopā abas fibroīna šķiedras, pirms tās iznāk no kāpura mutes.