Home / Saturniidae Moths (Saturniidae) / Regal Moth (Citheronia regalis)

Regal Moth (Citheronia regalis)

Regal moth, a native of North America, belongs to the Saturniidae family. Danish zoologist Jonathan Christian Fabricius described them first in 1793.

Regal Moth


Scientific Classification

  • Family: Saturniidae
  • Genus: Citheronia
  • Scientific Name: Citheronia regalis

Description and Identification


The larva at the onset is small with a yellow body. In the initial stages of their life, they are solitary feeders, eating primarily at night. During the day, they mostly remain curled up like a j-pattern, closely resembling a bird’s dropping. Each instar varies from the other in color and pattern, but in the fifth and final stage, they turn bright green and develop large red horn-like projections, tipped in black. At this time, they grow long enough to about 15 cm. They may look dangerous, but are completely harmless, as the spines do not sting and prick. When the larva is about to pupate, it expels its stomach and changes color from green to turquoise. Its skin at that moment is tight and a little stretched attaining a shiny texture.

Regal Moth Larva


Regal Moth Caterpillar



The pupa is black or dark brown with a comparatively small cremaster.

Regal Moth Pupa


Adult Moth

Sexual Dimorphism: Present

Color and Appearance: When opened, the forewings are grayish-green or gray with orange veins. It also has about nine yellow spots scattered throughout in rows. The hind wings are majorly orange with yellow spots or patches occupying the anal and costal margins. When closed, the color and pattern remain the same, with about four to five visible spots.

Though similar in color and pattern, male regal moths are smaller than their female counterparts.

Sexual Dimorphism: Present

Average wingspan: 9.5 – 15.5 cm

Flight pattern: Fast and erratic

Season: May to September

Citheronia regalis


Regal Moth Images



The eggs, oval and yellowish, hatch between six and ten days from being laid. They have a diameter of about 2mm. The female mostly lays the eggs singly or in a group of four on the upper sides of the host plants’ leaves.

Regal Moth Eggs


Quick Facts

Other NamesRoyal walnut moth, hickory horned devils ( as the larvae are called)
DistributionSeveral parts of the United States, including Pennsylvania, Massachusetts, Missouri, Texas, and Florida
HabitatDeciduous forest areas 
PredatorsSpecies of tachinid and sarcophagid flies, and also wasps
Lifespan of adultsApproximately 10 days
Host plantsCarya, Rhus, and Gossypium species,  Liquidambar styracifluaJuglans cinereaDiospyros virginiana   
Adult dietsMostly nectars

Did You Know

  • Since the larva mainly thrives on walnut leaves, they are known as the royal walnut moth.
  • The unique coloration and horned appearance of the larva in their last instar stage earns them the name hickory horned devil.
Regal Moth Pictures


Hickory Horned Devils


Royal Walnut Moth


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