Obviously a symbol of mortality. The symbol appears fairly frequently and appears in some American 3rd “craft” degree. Sometimes it is an element in the ‘preparation room’.
The Scythe
Is an emblem of Time, which cuts the brittle thread of life, and launches us into eternity. Behold ! what havoc the scythe of Time makes among the human race ! If by chance we should escape the numerous evils incident to childhood and youth, and with health and vigor arrive to the years of manhood ; yet, withal, we must soon be cut down by the all-devouring scythe
Ahiman Rezon. Rituals of Freemasonry by Daniel Sickels (1870)
cut-out from unknown Symbol Chart