Polyphemus moth vs Imperial moth
These two are easy to mix up. Here's how to tell a Polyphemus moth from an imperial moth, and whether either one bites or stings.
Polyphemus moth
Antheraea polyphemus
Imperial moth
Eacles imperialis
≠The key differences
Imperial moth has yellow and purple mottling and a different wing shape and pattern; no large round blue-centered eyespots like Polyphemus.
Polyphemus is tan to reddish-brown with a large eyespot containing a clear window on each hindwing, lacking the yellow ground colour and purple-brown blotches of the imperial moth.
⚖︎Side by side
| Polyphemus moth | Imperial moth | |
|---|---|---|
| To humans | Non-toxic | Non-toxic |
| Size | 11-15 cm wingspan | Wingspan 80-175 mm (3-7 inches), typically 90-150 mm in many populations |
| Colours | Reddish brown, Tan, Olive-brown, Sky blue (eyespot center) | Yellow, Orange, Rusty brown, Purple-brown markings |
| Family | Saturniidae | Saturniidae |
| Habitat | Deciduous woodlands, suburban yards, parks and areas with host trees | Deciduous and mixed woodlands, forest edges, suburban yards with host trees |
| Range | Widespread across much of the United States and southern Canada, extending into Mexico | Eastern and central North America from Canada (southern Ontario, Quebec) south through the eastern United States to Mexico; exact range and form vary regionally |
| Active | Spring and early summer (one or two broods depending on latitude); adults are nocturnal | Mostly spring to early autumn depending on location; adults are nocturnal and fly at night |
| Pest? | No | No |
🔍How to spot a Polyphemus moth
- Very large wingspan (11-15 cm) with broad, rounded wings
- Distinctive large circular eyespot on each hindwing with a clear center ringed with yellow, blue and black
- Overall reddish-brown to tan coloration with wavy crosslines across wings
- Males with notably feathered antennae; females with thinner antennae
🔍How to spot an imperial moth
- Large wingspan (typically 90-150 mm) with rounded fore- and hindwings.
- Ground colour yellow to orange with distinct purple-brown blotches and wavy crosslines.
- Small dark discal spot on each wing and males with feathery antennae.
- Caterpillars large, green or brown/orange, with long whitish hairs and short horns behind the head.
?Frequently asked questions
What is the difference between a Polyphemus moth and an imperial moth?
Imperial moth has yellow and purple mottling and a different wing shape and pattern; no large round blue-centered eyespots like Polyphemus. Polyphemus is tan to reddish-brown with a large eyespot containing a clear window on each hindwing, lacking the yellow ground colour and purple-brown blotches of the imperial moth.
Is a Polyphemus moth or an imperial moth more dangerous?
Polyphemus moth: Non-toxic. Imperial moth: Non-toxic. Polyphemus moths do not bite or sting. Imperial moths and their caterpillars are not venomous.
Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.