Polyphemus Moth vs Cecropia Moth
Antheraea polyphemus vs Hyalophora cecropia
Look at the spots. Polyphemus has one huge round eyespot in the middle of each hindwing. Cecropia has crescent-shaped red-and-white spots on all four wings and no eyespot. Both are enormous, both are harmless, and neither can bite — as adults they have no working mouthparts.
The one thing that settles it
Round eyespot versus crescent. The polyphemus eyespot is a large, round, staring eye ringed in yellow and blue, sitting in the middle of the hindwing. Cecropia has no such thing — its markings are crescent-shaped, red with a white centre, and the same on every wing. This is visible in any photograph that shows the moth with its wings open.
Side by side
| Character | Polyphemus Moth | Cecropia Moth |
|---|---|---|
| Danger | Harmless | Harmless |
| Hindwing marking | One huge round eyespot ringed in yellow and blue | A crescent-shaped red spot with a white centre |
| Overall colour | Tan to reddish brown | Charcoal to grey-brown with a band of red shading near the body |
| Body | Furry and the same colour as the wings | Fat, furry, banded in red and white |
| Size | Wingspan 100–150 mm | Wingspan 110–150 mm — the largest moth native to North America |
| Season | April–May and July–August in the south; a single May–July flight in the north | A single flight, early April into June |
| Cocoon | Spun in a leaf, often falling to the ground in autumn | A tough spindle bound lengthways along a twig, staying up all winter |
Why they get confused
They are both giant silkmoths, they are both far larger than anything else that turns up on a porch wall, and both are brownish at a glance in poor light — which is the light most people see them in, because both come to lamps at night. Anyone meeting one for the first time reaches for "huge brown moth", and that description fits either.
If you still can’t tell
Neither identification carries any risk, so take your time. If the wings are closed and you cannot see the markings, wait — both species sit still for hours and will usually open up. The cocoon is a good secondary clue if you find one in winter: cecropia's is bound along a twig and stays put, while polyphemus wraps a leaf that generally comes down with the leaf fall.
Common questions
What do I feed it?
Nothing. Adults of both species emerge without functioning mouthparts. They live one to two weeks on reserves built up as caterpillars, mate, and die. One dying a few days after you found it is not something you did.
Are they rare?
Not rare, just rarely seen. Polyphemus is the most widespread giant silkmoth on the continent and turns up in nearly every state. They fly at night and live about a week, so seeing one is a matter of timing.
Can either of them hurt me?
No. No sting, and no mouth to bite with. They are safe to let sit on your hand, and safe for children to look at closely.
Full records
- Polyphemus Moth Harmless
- Cecropia Moth Harmless
Where this was checked
- iNaturalist — Antheraea polyphemus checked 2026-07-30
- iNaturalist — Hyalophora cecropia checked 2026-07-30
- Missouri Department of Conservation — Polyphemus Moth 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.