Bug FAQMead's Sulphur
Colias meadii · Order: Lepidoptera · Family: Pieridae
Mead's sulphur is a small butterfly with a wingspan of 35 to 44 mm that lives in high-mountain arctic-alpine tundra and rocky slopes near the tree line. Its range covers the Rocky Mountains of Canada and the United States, and adults fly in July and August, feeding on alpine sunflower and aster nectar while the caterpillars eat various alpine legumes.
Source: Wikipedia
Size
Its wingspan ranges from about 35 to 44 millimetres.
Source: Wikipedia
Where it lives
It lives on arctic-alpine tundra and rocky slopes near the tree line in high mountains.
Source: Wikipedia
What it eats
Caterpillars feed on Trifolium species, Astragalus alpinus, Oxytropis deflexa and Vicia americana. Adults sip nectar from alpine sunflowers and asters.
Source: Wikipedia
Life cycle
Adults are on the wing from July through August.
Source: Wikipedia
When you see it
Their flight season occurs in midsummer, July and August.
Source: Wikipedia
Where it comes from
Its range includes the Rocky Mountains of Canada and the United States.
Source: Wikipedia
Where it is found in the US
Recorded in 10 of 51 states and DC. Most records: Colorado, Wyoming, Montana, Idaho, Utah, New Mexico, Kansas, Nebraska.
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 Mead's sulphur?
Adults fly in midsummer, typically from July to August.
Source: Wikipedia
What do the caterpillars eat?
The larvae feed on Trifolium, Astragalus alpinus, Oxytropis deflexa and Vicia americana.
Source: Wikipedia
What flowers do the adults visit?
Adults drink nectar from alpine sunflowers and asters.
Source: Wikipedia
Same family (Pieridae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Colias_meadii
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.