13 Types of Moths in Washington State, from Common Pests to a Record-Breaking Giant
October 10, 2026
In 2022, a University of Washington professor found something unexpected clinging to a garage wall in Bellevue: a moth with a wingspan of nearly 10 inches, the largest moth species ever recorded in the United States. That single sighting is a reminder that the types of moths in Washington state range from backyard nuisances to genuine biological rarities. Between invasive tree-defoliators, imperiled dune specialists, and giant silk moths with owl-like eyespots, the state’s moth population is far more varied than most residents realize.
This guide walks through 13 moths you’re likely to encounter across Washington, from the Puget Sound lowlands to the shrub-steppe east of the Cascades. Some are common garden visitors; others are protected species you may never see in person. For a broader look at the state’s insect life, the different types of insects found across ecosystems offer useful context for how moths fit into the bigger picture.
Pro Tip: Most moths are strongly attracted to porch lights and outdoor fixtures after dusk. Checking lit walls and windows between May and September is one of the easiest ways to spot several species on this list without any special equipment.
1. Yellow-collared Scape Moth
The yellow-collared scape moth (Cisseps fulvicollis) is a day-flying species that many people mistake for a wasp at first glance. Its slender black body and narrow, smoky wings give it a slightly menacing look, but the moth is harmless and gets its name from the thin yellow-orange band circling the back of its neck. It belongs to the tiger moth subfamily within Erebidae, a group known for producing several wasp and bee mimics.
This species favors open, sunny habitats such as meadows, roadsides, and wetland edges, where the caterpillars feed on grasses and sedges. Because so many stinging insects share similar coloring, homeowners sometimes confuse this moth with the stinging insects found in Washington state, even though it has no stinger and poses no threat to people or pets.
2. Spongy Moth
The spongy moth (Lymantria dispar) is one of the most closely watched invasive insects in the Pacific Northwest. According to the Washington State Department of Agriculture, the caterpillars start out extremely tiny but rapidly grow up to 3 inches long, and can be identified by a yellow head, hairy body, and a distinctive row of five blue dot pairs followed by six pairs of red dots along the back.
The species is considered one of the worst forest pest insects in the country, capable of stripping leaves from more than 500 kinds of trees and shrubs, according to the Washington Invasive Species Council. Most new populations arrive on vehicles, firewood, or outdoor gear brought in by travelers, and the council notes that Washington sees new introductions every year despite ongoing eradication efforts. State agriculture crews place roughly 20,000 traps across Washington each summer to catch new arrivals before they can establish.
Important Note: This species was long known as the “gypsy moth.” The Entomological Society of America formally adopted “spongy moth” as the accepted common name, a change reflected in current state and federal pest-tracking materials.
3. Tent Caterpillar Moth
Unlike its invasive relative, the tent caterpillar moth is a native species that Washington residents encounter every spring without much cause for alarm. The Washington State Department of Agriculture notes that the tent caterpillar is very common in Washington and is much less destructive than the spongy moth. The caterpillars are easy to tell apart once you know what to look for.
Tent caterpillars build obvious silk tents in the forks of tree branches each spring, while spongy moths never construct tents at all. Coloring offers another clue: tent caterpillars tend to show orange and blue markings rather than the paired blue and red dots seen on spongy moth larvae. Gardeners dealing with similar defoliating pests elsewhere might also compare notes with growers facing the types of insects found in Ohio, where related tent-building caterpillars are equally common each spring.
4. Big Poplar Sphinx Moth
Among the state’s heavyweight moths, the big poplar sphinx moth (Pachysphinx occidentalis) stands out for sheer bulk. Moth identification resources note that Washington is home to some stunningly beautiful moths, with the largest belonging to the silkmoth and hawk moth families, and the big poplar sphinx is frequently cited as one of the largest species found in the state.
This sphinx moth has heavy, mottled gray-brown forewings that resemble tree bark at rest, but a sudden flash of blue or pink patches on the hindwings when disturbed. Caterpillars feed on poplar, cottonwood, and willow leaves, which keeps this species tied closely to riparian corridors. Its range extends well beyond Washington into neighboring provinces, overlapping with many of the types of insects found in Canada that share similar poplar and willow habitat.
5. Polyphemus Moth
Few moths in Washington draw more attention than the polyphemus moth (Antheraea polyphemus). According to Bird Watching HQ, Polyphemus Moths are easily recognized for their large, stunning eyespots, and the pattern on the upper wings closely resembles the face of a great horned owl, a trait that startles predators long enough for the moth to escape.
In Washington, this giant silk moth turns up in forests, orchards, wetlands, and urban areas, and it is easily spotted thanks to its size and coloring. Its adult life is remarkably brief: Polyphemus Moths have an extremely short lifespan as adults, living only about four days, just long enough to mate and lay eggs before dying. Moth enthusiasts tracking the species elsewhere can compare sightings with the types of moths in Florida, where the same species also appears in a very different climate.
6. Ceanothus Silkmoth
The ceanothus silkmoth (Hyalophora euryalus) is another giant silk moth with a striking visual signature. Bird Watching HQ describes how the easiest way to identify this species is the comma-shaped marking on their wings, sometimes likened to the “Nike Swoosh.” Coloring varies widely across its range, but that curved mark is a consistent identifier.
These moths occupy a wide range of elevations and habitat types, and researchers note they can be found in coastal forests, montane woodlands, mixed hardwood forests, and hilly brushland. They produce just one generation per year, with adults typically emerging between January and July depending on elevation. Anyone cataloging Washington’s larger insects alongside this species might also browse the types of beetles in Washington state for a sense of how many other oversized insects share the same forest habitats.
7. Pug Moth
Pug moths belong to the genus Eupithecia, a sprawling group of small geometrid moths documented across Washington by regional identification databases. Unlike the giant silk moths on this list, pugs rarely exceed an inch in wingspan, and their gray or brown mottled patterns make them easy to overlook against tree bark or fence posts.
Because the genus contains dozens of look-alike species, positive identification often requires close inspection of wing venation or, in scientific settings, genitalia comparison. For casual observers, the safest approach is simply recognizing the general pug shape: a small, wedge-like moth that rests with its wings flattened against a surface. Anyone curious about how such tiny species compare to insects worldwide can look at the broader different types of insects found across various families and orders.
8. Fall Webworm Moth
The fall webworm moth (Hyphantria cunea) lives up to its name by showing up later in the season than most defoliating caterpillars. The Washington State Department of Agriculture notes that the fall webworm, as its name implies, appears in the fall and begins to feed on trees, producing webs that can look similar to spring tent caterpillar nests at first glance.
The two are simple to distinguish once compared side by side. Fall webworm caterpillars are usually brownish in color and lack the blue and red spots of the spongy moth, and their webbing tends to enclose leaves at branch tips rather than forming a tight tent in a branch fork. Because this species also ranges widely across the southern United States, it’s worth comparing notes with residents dealing with similar late-season pests among the types of insects in Texas.
9. White-lined Sphinx Moth
The white-lined sphinx moth (Hyles lineata) is one of the more theatrical moths a Washington gardener might encounter, mostly because it’s so often misidentified as something else entirely. Bird Watching HQ points out that White-lined Sphinx Moths in Washington are sometimes mistaken for hummingbirds, since they can rapidly beat their wings to hover at flowers and reach in to sip nectar with their long proboscis.
Look closely and the differences are obvious: the moth has a heavy, torpedo-shaped body, olive-brown forewings streaked with white lines, and pink-and-black hindwings. It’s active at dusk and dawn, feeding on a wide range of garden flowers, which makes it a familiar sight in pollinator gardens. Gardeners comparing notes on this fast-flying species can also check the types of moths in Texas, another state where this same sphinx moth is common.
10. Sand-verbena Moth
Few moths on this list carry the conservation weight of the sand-verbena moth (Copablepharon fuscum). The Washington Department of Fish and Wildlife notes the species was discovered on a few coastal beach sites on Vancouver Island, British Columbia, Canada, and Whidbey Island, in northwestern Washington, and described as a new species in 1995. It remains one of the rarest moths documented in the state.
Its entire life cycle depends on yellow sand-verbena, a dune plant found only on a handful of beaches. A 2025 report covered by news coverage of a Center for Biological Diversity lawsuit notes that the sand-verbena moth, Copablepharon fuscum, is found on a few coastal beaches on Vancouver Island, British Columbia and Whidbey Island, with just six known populations remaining, three of them at Cattle Point/American Camp, Deception Pass, and Fort Worden. The Entomological Society of Canada adds that the species is considered an endangered species under Canada’s Species at Risk Act, even though it has not yet received the same formal protection south of the border.
Key Insight: The sand-verbena moth is currently classified as a Species of Greatest Conservation Need in Washington. Reporting sightings to WDFW helps biologists track one of the state’s most vulnerable insects, much the way birdwatchers track rare sightings among the types of eagles in Washington state.
11. Atlas Moth
The atlas moth (Attacus atlas) is not native to Washington, which is exactly what made its 2022 discovery in Bellevue such a notable event. NBC News reported that a moth with a wingspan of 10 inches has been found in the U.S. for the first time, after a University of Washington professor spotted it and reported it to state officials. Sven Spichiger, the state’s managing entomologist, called it a “‘gee-whiz’ type of insect, because it is so large.”
Native to Southeast Asia’s tropical forests, the atlas moth is prized in the exotic silk moth hobby, which is the most likely explanation for how one ended up on a Bellevue garage wall. The Washington Department of Agriculture asked residents to report any additional sightings, since an established population could threaten native tree species. Anyone interested in how exotic moths end up far from their native range might also enjoy learning about the types of insects kept as pets, a hobby that occasionally leads to accidental releases like this one.
12. Riding’s Forester Moth
Riding’s forester moth (Androloma maccullochii) is a day-flying species with a look that surprises people expecting typical nocturnal moth camouflage. Its wings are glossy black with scattered white or cream spots, giving it a pattern more reminiscent of a butterfly than a moth. It’s most often seen in open woodland edges and clearings where its host plants, wild grape and Virginia creeper, grow along fences and forest margins.
Because it flies during daylight hours and visits flowers for nectar, this species is frequently mistaken for a small butterfly rather than logged as a moth sighting. Ground-dwelling insects like ants often share the same forest-edge habitat that this moth’s caterpillars favor, which makes it worth cross-referencing sightings with the types of ants in Washington state when surveying a particular clearing or trailhead.
13. Ornate Tiger Moth
The ornate tiger moth (Apantesis ornata) rounds out this list as one of the more colorful tiger moths found in Washington’s drier eastern habitats. Adults show a bold combination of black, cream, and orange-pink patterning on the wings and abdomen, a warning coloration typical of the broader tiger moth group that signals unpalatability to predators.
Caterpillars of this species are generalist feeders on low-growing plants and are most active in open grassland and shrub-steppe country east of the Cascades. Because tiger moth caterpillars and adults are a known food source for insect-eating songbirds, they play a small but real role in supporting the diets of the types of finches found in Washington state and other seed- and insect-eating birds common to the same shrub-steppe landscape.
Comparing Washington’s Giant Moths at a Glance
Several species on this list stand out simply because of their size. The table below compares the state’s largest and most notable moths side by side for quick reference.
| Common Name | Approximate Wingspan | Status in Washington |
|---|---|---|
| Atlas Moth | Up to 10 inches | Non-native, exotic escapee |
| Big Poplar Sphinx Moth | 4–5.5 inches | Native |
| Polyphemus Moth | 4–6 inches | Native |
| Ceanothus Silkmoth | 3–4 inches | Native |
| White-lined Sphinx Moth | 2.5–3.5 inches | Native |
| Sand-verbena Moth | About 1.4–1.6 inches | Native, Species of Greatest Conservation Need |
| Pug Moth | Under 1 inch | Native |
The size range in that table alone helps explain why moth identification in Washington can be so confusing for beginners: a garden visitor might genuinely be a 5-inch giant silk moth one week and a moth barely bigger than a fingernail the next. For readers comparing regional insect diversity more broadly, the wide contrast between an inch-long pug moth and a tropical atlas moth escapee is a small-scale version of the differences seen among the types of insects found in the Amazon rainforest, where scale and camouflage vary just as dramatically.
Washington’s moth population reflects the state’s own geographic split between wet coastal forests and dry eastern shrub-steppe, which is why native giants like the polyphemus and ceanothus silkmoth share the landscape with fragile specialists like the sand-verbena moth and occasional invasive surprises like the spongy moth. Learning to tell these species apart, whether by wingspan, host plant, or flight season, makes it easier to know when a sighting is simply a curious backyard visitor and when it’s worth reporting to state wildlife or agriculture officials.