Douglas Fir Tussock Moth (Orgyia pseudotsugata)

Caterpillar

They have a light tan or dark gray body, covered with long black hairs emerging from tiny red tubercles, and initially measure 3-6mm. Upon maturation, the hair on their dorsal region eventually thickens to form four tufts of hair or tussocks marked with brown or reddish tips. Fully mature caterpillars have two black hairy “horns” right behind their head that project forward and another horn protruding from their posterior ends. On reaching their final instar, they can reach lengths of up to 3.2 cm.

Alchetron.com

Pupa

They appear light to dark brown, covered with short, straw-colored hairs. Pupae remain encased within a gray cocoon, shaped like a spindle, partially made out of shed larval hairs.

Upload.wikimedia.org

Adult Moth

Sexual Dimorphism: Present

The females have tiny wings that do not allow them to fly and threadlike antennae. In contrast, males have much larger wings and feathery antennae. Males are also larger at a length of 3.2 cm compared to females measuring 1.9 cm.

Color and Appearance:

Their bodies are gray-brown, with the females being darker near the posterior end.

Forewings: When they are open, two white spots are observed near the outer edges, alongside two faint wavy black bands against a grayish-brown background with a mottled pattern. When closed, the patterns remain visible but less prominent.

Hindwings: They are brown and seen only when the wings are opened.

The moths inhabiting the northern region of their range have an overall darker coloration than their southern counterparts.

Average wingspan: 2.5 – 3.2 cm

Flight pattern: Consistent

Season: July/August to November

Extension.usu.edu

Egg

Eggs are white, 1.3 cm in diameter, and laid in large masses of up to 350 to protect them in winter. They hatch in spring.

Bugwoodcloud.org