Bug FAQMourning Ethmia
Ethmia semilugens · Order: Lepidoptera · Family: Ethmiidae
The moth has forewings 8.7 to 12 mm long and a brown-black ground color with a wide white edge along the dorsal side. It lives in arid parts of the southwestern United States and northern Mexico, where the larvae feed openly on the leaves of Phacelia calthifolia and Phacelia crenulata.
Source: Wikipedia
How to recognize it
The forewings are brownish-black with a broad white margin along the dorsal edge. The hindwings are whitish, becoming brownish toward the apex and often mostly brown except near the base.
Source: Wikipedia
Size
Forewing length ranges from about 8.7 to 12 mm (0.34 to 0.47 in).
Source: Wikipedia
Where it lives
It inhabits arid regions from Colorado through central Texas, New Mexico, Arizona, southern California, and into northern Chihuahua, Mexico.
Source: Wikipedia
What it eats
Larvae feed on the leaves of Phacelia calthifolia and Phacelia crenulata in California. The caterpillars live openly on the leaves without building shelters.
Source: Wikipedia
Life cycle
There are two generations each year.
Source: Wikipedia
When you see it
Adults are on the wing from late February to March in southwestern Texas and continue through September in Chihuahua.
Source: Wikipedia
Where it comes from
Its native range includes the United States and Mexico in the dry western and southwestern areas.
Source: Wikipedia
Where it is found in the US
Recorded in 8 of 51 states and DC. Most records: Texas, Colorado, New Mexico, Nevada, California, Oklahoma, Arizona, Wyoming.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in United States. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
When are the adult moths active?
Adults fly from late February through March in southwestern Texas and can be seen as late as September in Chihuahua.
Source: Wikipedia
What do the larvae eat?
The caterpillars feed on the leaves of Phacelia calthifolia and Phacelia crenulata.
Source: Wikipedia
Where is this moth found?
It lives in arid parts of the southwestern United States and northern Mexico, from Colorado and Texas to Arizona, southern California, and northern Chihuahua.
Source: Wikipedia
Same family (Ethmiidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Ethmia_semilugens
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.