Project Noah

Project Noah is a tool to explore and document wildlife and a platform to harness the power of citizen scientists everywhere.

Join Project Noah Today

Evergreen Bagworm

Thyridopteryx ephemeraeformis


The Evergreen Bagworm is a moth that spins its cocoon all its larval life, decorating it with bits of plant material from the trees on which it feeds, so what you see here is the cocoon. Newborn larva are blackish and turn brown to tan as they grow, mottled with black. Adult males resemble bees, having a 25 mm wingspan with transparent wings and black furry bodies. Adult females are wingless, maggot-like with yellowish-white soft bodies 19 to 23 mm long and small tufts of hair near the end of the abdomen. The evergreen bagworm thrives in the eastern United States as far west as Nebraska, north into New England and bordering the Gulf of Mexico south throughout Texas. Large populations in forested areas are rare. With scarce predators in urban areas, evergreen bagworms often thrive in urban habitats.


Arborvitae and red cedar are the favored hosts trees of the evergreen bagworm, but cypress, juniper, pine, spruce, apple, birch, black locust, elm, maple, poplar, oak, sycamore, willow, and over 100 other species are also attacked. Leaves and buds are both fair game for food.


Eggs hatch from early April to early June (earlier in the south) and larvae emerge from the carcass of their mother in her case. Newborn larva emerge from the bottom of the hanging case and drop down on a strand of silk. The wind often blows the larva to nearby plants where it begins its new case from silk and fecal material before beginning to add leaves and twigs from its host. When mature in mid-August, the larva wraps silk around a branch, hangs from it, and pupates head down. Adult males transform into moths in four weeks to seek out females for mating. The female never leaves the cocoon, requiring that the male mate with her through the open end at the back of the case. She has no eyes, legs, wings, antennae, and can't eat, but she emits a strong pheromone to attract a mate. After her death with hundreds to several thousand eggs still inside, her offspring hatch and pass through her body, pupal shell and case over several months emerging to start their own cases. Later, her pupal case can be found, full of the yellow remains of eggshells.

No species ID suggestions

1 Comment

keithp2012 7 years ago

Evergreen Bagworm

New York, USA

Lat: 40.70, Long: -73.35

Spotted on Sep 13, 2010
Submitted on Sep 14, 2010

Related spottings

Bagworm Bagworm Moth Bagworm Moth Evergreen Bag Worm Moth Bag

Nearby spottings

"Ice King" Daffodil Flowering Plum European Beech Ring-Billed Gull