Bug FAQConfusing Petrophila
Petrophila confusalis · Order: Lepidoptera · Family: Crambidae
Its forewings measure between 5 and 11 mm in length. The species lives near fast-moving streams and feeds as a caterpillar on green algae and diatoms.
Source: Wikipedia
How to recognize it
Petrophila confusalis, called the confusing petrophila moth, belongs to the Crambidae family.
Source: Wikipedia
Size
The forewing length ranges from 5 to 11 mm.
Source: Wikipedia
Where it lives
It is found living in and around fast-moving (lotic) streams.
Source: Wikipedia
What it eats
Caterpillars eat green algae and diatoms such as Cladophora, Synedra ulna and Gomphonema olivaceum.
Source: Wikipedia
Life cycle
The species was first described by Francis Walker in 1866.
Source: Wikipedia
When you see it
Adults are on the wing from April through September.
Source: Wikipedia
Where it is found in the US
Recorded in 12 of 51 states and DC. Most records: California, Oregon, Montana, Idaho, Washington, Nevada, Wyoming, Illinois.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
When are adult confusing petrophila moths active?
Adults fly from April to September.
Source: Wikipedia
Same family (Crambidae)
Box Tree MothCydalima perspectalisDamages trees, gardens or crops
Celery Leaftier MothUdea rubigalisDamages trees, gardens or crops
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/Petrophila_confusalis
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-24 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-24.