Cecropia Moth

Hyalophora cecropia

Cecropia Moth

Hyalophora cecropia

Harmless

Not dangerous

Harmless. The largest moth native to North America has no sting and no working mouthparts — it cannot bite, and it cannot feed. Nothing about its size makes it dangerous.

SizeWingspan 110–150 mm

MarkingsEnormous — wingspan up to about 150 mm, the largest native moth on the continent · Charcoal to grey-brown wings with a band of red shading near the body

WhereWoodland edges, hedgerows, parks and suburban gardens with broad-leaved trees. Adults come to lights at night.

SeasonAdults fly from early April into June, in a single brood

How to tell it apart

Enormous — wingspan up to about 150 mm, the largest native moth on the continent
Charcoal to grey-brown wings with a band of red shading near the body
A crescent-shaped red spot with a white centre on every wing, not a round eyespot
A fat red-and-white banded body, noticeably furry
Broad feathery antennae mean a male

Where you’ll find it

Most of North America east of the Rocky Mountains — from the Canadian Maritimes south to central Florida and west across the eastern plains.

Woodland edges, hedgerows, parks and suburban gardens with broad-leaved trees. Adults come to lights at night.

Adults fly from early April into June, in a single brood.

How it behaves

Adults emerge from a large papery cocoon fastened lengthways to a twig, usually in the morning, and are on the wing for about two weeks. They do not feed. Males find females by scent alone and will travel a long way on it. The caterpillar is as striking as the adult: very large, sea-green with rows of orange, yellow and blue knobs along its back and sides.

You’ve found one indoors

Nothing needs doing. If you find a cocoon on a twig in winter, leave it where it is — moving it indoors makes the moth emerge months early into a house with nothing to mate with. If you want to help the species, the useful thing is leaving leaf litter and native shrubs alone.

Common questions

Is this the biggest moth in North America?

Yes, by wingspan it is the largest moth native to the continent, reaching about 150 mm across. The polyphemus moth runs it close.

Do cecropia moths bite?

No. The adults have small or absent mouthparts and cannot eat, let alone bite. They live about two weeks on reserves built up as a caterpillar.

What do the caterpillars eat?

A wide range of broad-leaved trees and shrubs — maples including box elder, willows, cherries, plums, apples, dogwoods and lilacs among many others. They do not occur in numbers that damage a tree.

I found a big brown papery cocoon on a branch. Is it this?

Very likely. Cecropia spins a tough spindle-shaped cocoon bound along the length of a twig, so it stays attached through winter rather than dropping with the leaves. Leave it outside and it will emerge in spring.

Commonly confused with

Polyphemus Moth Harmless
Luna Moth Harmless

Side-by-side comparisons

Polyphemus Moth vs Cecropia Moth

Keep identifying

Identify another animal from a photo or return to the Moths guide.

Next: Hummingbird Moth

Where this was checked

BugGuide — Hyalophora cecropia (Cecropia Moth, Hodges#7767) checked 2026-07-30
Missouri Department of Conservation — Cecropia Moth checked 2026-07-30

Last reviewed 2026-07-30. We identify, we don’t diagnose — what we can and can’t tell you.