Bug FAQHarris's Three-Spot
Harrisimemna trisignata · Order: Lepidoptera · Family: Noctuidae
Also called: Harris Threespot, Harris' Three Spot, Harris's Three-spot Moth
The adult moth has a wingspan of about 30 to 36 mm. It lives across much of North America, from Canadian provinces such as Ontario and Nova Scotia down to U.S. states as far south as Arizona.
Source: Wikipedia
How to recognize it
Harris's three-spot moth belongs to the Noctuidae family.
Source: Wikipedia
Size
Wingspan ranges from 30 to 36 mm.
Source: Wikipedia
Where it lives
Found in many parts of North America, from eastern and central Canada to the western United States.
Source: Wikipedia
When you see it
Adults are active from May through August in Canada.
Source: Wikipedia
Where it comes from
Its native range covers Canadian provinces and U.S. states including Arizona.
Source: Wikipedia
Where it is found in the US
Recorded in 39 of 51 states and DC. Most records: Massachusetts, Texas, Ohio, Michigan, Alabama, New York, Connecticut, Louisiana.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada; native in United States. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
When can I see adult Harris's three-spot moths?
Adults are on the wing from May to August in Canada.
Source: Wikipedia
Same family (Noctuidae)
Ipsilon Dart MothAgrotis ipsilonDamages trees, gardens or crops
Fall Armyworm MothSpodoptera frugiperdaDamages trees, gardens or crops
Army Cutworm MothEuxoa auxiliarisDamages trees, gardens or crops
Large Yellow UnderwingNoctua pronubaDamages trees, gardens or crops
Silver ΥAutographa gamma
American DaggerAcronicta americanaCan irritate skinSources
- Wikipedia: https://en.wikipedia.org/wiki/Harrisimemna_trisignata
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-23.