Bug FAQAchyra occidentalis
Achyra occidentalis · Order: Lepidoptera · Family: Crambidae
The western yellow moth has forewings that measure about 10 to 12 mm long. It occurs in the western United States, specifically Arizona, California and Nevada. Two colour forms exist: a dark form that flies in early spring and a pale form that appears in summer.
Source: Wikipedia
How to recognize it
There are two colour forms, one dark and one pale.
Source: Wikipedia
Size
The forewings are 10 to 12 mm (0.39 to 0.47 in) long.
Source: Wikipedia
Where it lives
It has been recorded in Arizona, California and Nevada.
Source: Wikipedia
Life cycle
Adults of the dark form appear in early spring, while adults of the pale form appear in summer.
Source: Wikipedia
When you see it
Dark-form adults are on the wing from March to April. Pale-form adults are on the wing from June to August.
Source: Wikipedia
Where it comes from
It is native to North America, found in the western United States.
Source: Wikipedia
Where it is found in the US
Recorded in 4 of 51 states and DC. Most records: California, Idaho, Arizona, Washington.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
When can I see these moths?
The dark form flies from March to April and the pale form from June to August.
Source: Wikipedia
Where are they found?
They have been recorded in Arizona, California and Nevada in the United States.
Source: Wikipedia
Same family (Crambidae)
Box Tree MothCydalima perspectalisDamages trees, gardens or crops
Celery Leaftier MothUdea rubigalis
Elegant Grass-veneerMicrocrambus elegans
Hawaiian Beet Webworm MothSpoladea recurvalisDamages trees, gardens or crops
Garden Grass-veneerChrysoteuchia culmellaDamages trees, gardens or crops
Bluegrass Webworm MothParapediasia teterrellusDamages trees, gardens or cropsSources
- Wikipedia: https://en.wikipedia.org/wiki/Achyra_occidentalis
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-27 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-27.