I was about to tie up this streamer pattern but realized I didn't understand the recipe. Hoping someone can help. Here are the ingredients of the recipe, as written:
TAG Flat silver tinsel
TAIL Red schlappen
BODY Flat silver tinsel
BELLY White bucktail
THROAT Black schlappen
UNDERWING Four to six peacock herls
WING Four black hackles
CHEEK Jungle cock
TOP Red schlappen
HEAD Carrie Stevens tied it with a black head with an orange band
SOURCE Flat silver tinsel

What part of the fly is the 'Source'? I've never come across that term.

Thanks in advance.

Allan