Bug FAQLethal Pyrausta
Pyrausta lethalis · Order: Lepidoptera · Family: Crambidae
Also called: Lethal Pyrausta Moth
The Lethal Pyrausta has a wingspan of about 16 mm and shows purplish-brown forewings with a dark exterior line, a pale-brown subterminal area shaded whitish, and pale fuscous hindwings with a black terminal line. It occurs in the southwestern United States, from California’s Mojave Desert and Los Angeles through southern Nevada and Arizona to Texas’s Big Bend region. Adults are on the wing from March through October.
Source: Wikipedia
How to recognize it
The area near the wing edge is pale brown with whitish shading. Hindwings are pale fuscous and end with a black line.
Source: Wikipedia
Size
The wingspan measures about 16 mm.
Source: Wikipedia
Where it lives
It is found in North America, recorded from California, Nevada, Arizona and Texas.
Source: Wikipedia
When you see it
Adults have been observed flying from March to October.
Source: Wikipedia
Where it comes from
Its native range is North America, specifically the western and southwestern United States.
Source: Wikipedia
Where it is found in the US
Recorded in 9 of 51 states and DC. Most records: California, Texas, Arizona, New Mexico, Montana, Colorado, Nebraska, Oregon.
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 are Lethal Pyrausta adults active?
Adults are on the wing from March through October.
Source: Wikipedia
Where might I find a Lethal Pyrausta?
They have been recorded in California’s Mojave Desert and Los Angeles, southern Nevada, southern Arizona, and Texas’s Big Bend region.
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/Pyrausta_lethalis
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.