Home / Saturniidae Moths (Saturniidae) / Ceanothus Silk Moth (Hyalophora euryalus)

Ceanothus Silk Moth (Hyalophora euryalus)

The Ceanothus Silk Moth is a member of the family of saturniid moths. They are found in North America in dry and temperate parts of the continent.

Ceanothus Silk Moth


Scientific Classification

  • Family: Saturniidae
  • Genus: Hyalophora
  • Scientific Name: Hyalophora euryalus

Description and Identification


The larva changes color through its various instars, with the mid instar being brightly colored with yellow spines. Whereas. in the later instars it turns green with white spines.

Ceanothus Silk Moth Caterpillar



They overwinter as a pupa inside a teardrop-shaped cocoon, attached to a twig or a leaf on the outer part of the host plant.

Ceanothus Silk Moth Cocoon


Adult Moth

Sexual Dimorphism: Present. The antennae of the male is more feathery than the female, while the abdomen of the female is larger than the male.

Color and Appearance

Forewing: When the wings are opened, they are red to brownish red. When the wings are closed, the areas outside the thin white postmedian lines are also red to brownish red, but with black over scaling.

Hindwing: When the wings are opened, they show similar coloration to the forewing. A white discal spot shaped like a comma can be seen on the wing. When the wings are closed, the comma like spot remains visible.

Average wingspan: 8.9 – 12.7 cm

Flight pattern: Erratic

Season: January to July


The eggs can be either laid singly or in clusters. They are glued to the host plant by the females.

Ceanothus Silk Moth Eggs


Quick Facts

Other namesRobin moth
DistributionNorth America, ranging from British Columbia to western Montana, south through west coast states to Baja California.
HabitatChaparral forests, coastal areas, conifer forests, and intermontane valleys
Lifespan of Adults7 days
PredatorsBirds like jays and woodpeckers, deer mice and other rodents, and some parasitoid flies
Host PlantsAlder, buckbrush, gooseberry, madrone, manzanita, mountain mahogany, and willow
Adult DietDoes not feed

Did You Know

  • French lepidopterist Jean Baptiste Alphonse Déchauffour de Boisduval first described this species in 1855.
Ceanothus Silk Moth Image


Hyalophora euryalus


Picture of Ceanothus Silk Moth


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