Bug FAQSilvery Blue
Glaucopsyche lygdamus · Order: Lepidoptera · Family: Lycaenidae
The silvery blue butterfly has a wingspan of about 18 to 28 mm and shows light blue uppersides in males and dull gray-blue in females. It lives in many western North American habitats such as alpine meadows, dunes, shale barrens, and wooded areas, and its larvae feed on lupine plants.
Source: Wikipedia
Size
Wingspan ranges from 18 to 28 mm.
Source: Wikipedia
What it eats
Caterpillars feed on Lupinus (lupine) plants.
Source: Wikipedia
Lookalikes
Eastern tailed-blue (Cupido comyntas) and western tailed-blue (Cupido amyntula) look similar but have small tails on the hindwings.
Source: Wikipedia
Where it is found in the US
Recorded in 45 of 51 states and DC. Most records: California, Vermont, Alaska, Oregon, Washington, Colorado, Michigan, Idaho.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in United States; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
Can I confuse a silvery blue with a tailed-blue butterfly?
Yes, the eastern and western tailed-blue species look similar but can be told apart by the tiny tails on their hindwings.
Source: Wikipedia
Same family (Lycaenidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Glaucopsyche_lygdamus
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.