Bug FAQFrosted Elfin
Callophrys irus (formerly Thecla irus) · Order: Lepidoptera · Family: Lycaenidae
How to recognize it
The underside of the hindwings is frosted gray with a dark spot and an irregular dark line.
Source: Wikipedia
Size
Adults are slightly larger than most similar elfins, ranging from about 1.00 to 1.25 inches (26 to 32 mm).
Source: Wikipedia
Where it lives
Historically it inhabits natural barrens, grassy openings, and savannahs. It prefers very dry, sandy soils, though the Baptisia-feeding form can also occupy rocky outcrops and glacial till.
Source: Wikipedia
What it eats
Caterpillars eat the flowers and developing seedpods of their host plants. Larval host plants include members of the pea family such as Baptisia tinctoria, Lupinus perennis and Crotalaria sagittalis.
Source: Wikipedia
Life cycle
The entire life cycle is completed within one year. Chrysalids hibernate in loosely formed cocoons beneath leaf litter below the host plant.
Source: Wikipedia
When you see it
In the southern part of its range adults fly from March to April; in the north they are on the wing from mid-May to early June.
Source: Wikipedia
Where it comes from
The frosted elfin is native to North America.
Source: Wikipedia
Where it is found in the US
Recorded in 25 of 51 states and DC. Most records: Massachusetts, New York, Connecticut, New Jersey, New Hampshire, Texas, Michigan, North Carolina.
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 a frosted elfin?
In the south they fly in March-April; in the north they appear from mid-May to early June.
Source: Wikipedia
What plants do frosted elfin caterpillars eat?
They feed on flowers and seedpods of plants in the pea family, such as Baptisia, lupine and rattlebox.
Source: Wikipedia
Where does the frosted elfin live?
It prefers dry, sandy habitats like natural barrens and grassy openings, and is also common on human-made sites such as powerlines and gravel roads.
Source: Wikipedia
How big is a frosted elfin?
Adults have a wingspan of about 1 to 1.25 inches (26 to 32 mm).
Source: Wikipedia
Same family (Lycaenidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Callophrys_irus
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-24 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-24.