What are these paper-mache-like hexagonal cells doing on the ground?
These are the remains of a bald-faced hornet nest! These large black and white yellowjackets create their papery nests by combining saliva with chewed wood. Legend has that they inspired paper making in China. The inside of the nest is made up of horizontal tiers of brood comb, the paper cells in which eggs are laid and young are raised. The outer nest is an insulating multi-layered paper ball with an entrance/exit hole at the bottom. The different colored stripes are from different kinds of wood, and each stripe represents a single hornet’s contribution.
So why is the nest on the ground at this time of year? In the fall, the queen lays her last eggs as fertile males and females (new queens). These offspring disperse and mate, and the males die soon after. This is the end of the functioning colony, and the ruling queen and workers also die (mid-September through late November depending on the size of the nest). The nest is then abandoned (if there are any dead larvae inside they might be eaten by gorging bears or Bohemian Waxwings). The newly fertilized queens spend the winter dormant in crevices, under bark, or rotting logs and emerge in the spring to begin their own nests.
In New England, after a few hard frosts is the time of year to go for a nest search and dissect one!