Bug FAQHemlock Looper Moth
Lambdina fiscellaria · Order: Lepidoptera · Family: Geometridae
Also called: Hemlock Looper, Mournful Thorn
Source: Wikipedia
The hemlock looper moth has a wingspan of about 35 mm and belongs to the Geometridae family.
Source: Wikipedia
Size
The moth’s wingspan is roughly 35 mm.
Source: Wikipedia
Life cycle
Adults are on the wing from August through early October, depending on location.
Source: Wikipedia
When you see it
Flight season runs from August to early October.
Source: Wikipedia
Where it comes from
Its native range covers the same North American area as its habitat.
Source: Wikipedia
Lookalikes
It is a member of the Geometridae family, which includes many similar-looking moths.
Source: Wikipedia
Where it is found in the US
Recorded in 38 of 51 states and DC. Most records: Vermont, Massachusetts, Idaho, Maine, New York, New Hampshire, Washington, Pennsylvania.
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
Are they a problem for my garden or trees?
Yes, their caterpillars feed on a variety of trees such as hemlock, fir, spruce and oak, which can damage foliage.
Source: Wikipedia
Same family (Geometridae)
Willow BeautyPeribatodes rhomboidaria
Pale BeautyCampaea perlataDamages trees, gardens or crops
Large Lace-border MothScopula limboundataDamages trees, gardens or crops
Riband WaveIdaea aversata
Yellow Shell MothCamptogramma bilineata
Large Maple Spanworm MothProchoerodes lineolaDamages trees, gardens or cropsSources
- Wikipedia: https://en.wikipedia.org/wiki/Lambdina_fiscellaria
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-22 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.