Bug FAQRocky Mountain Parnassian
Parnassius smintheus · Order: Lepidoptera · Family: Papilionidae
Also called: Mountain Parnassian
The Rocky Mountain Parnassian is a white to pale yellow-brown butterfly with red and black spots that warn predators it tastes bad. It lives in sunny mountain meadows of the Rocky Mountains from Yukon and Alaska down to New Mexico, avoiding forested areas.
Source: Wikipedia
How to recognize it
Its wings are mostly white or pale yellow-brown with contrasting red and black markings that signal unpalatability.
Source: Wikipedia
Where it lives
It prefers open meadows and stays away from forests because it likes bright light.
Source: Wikipedia
What it eats
Caterpillars feed on the leaves of the plant Sedum lanceolatum, while adults sip nectar from flowers.
Source: Wikipedia
Life cycle
From November to February the host plant’s leaves are toxic, killing any larvae that try to eat them. If snow melts early, eggs may hatch while the leaves are still poisonous, causing the larvae to die.
Source: Wikipedia
When you see it
Males emerge from pupae before females and patrol for newly emerged females that have not yet taken flight.
Source: Wikipedia
Where it comes from
The species is native to the Rocky Mountains of North America. Its range includes the mountainous regions of Yukon, Alaska, British Columbia, and extends south to New Mexico.
Source: Wikipedia
Lookalikes
It is often confused with the closely related Parnassius phoebus, a Holarctic species. Some researchers split the North American population into two or three separate species.
Source: Wikipedia
Where it is found in the US
Recorded in 16 of 51 states and DC. Most records: Colorado, Wyoming, Montana, South Dakota, Washington, Idaho, California, Utah.
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
What does the Rocky Mountain Parnassian look like?
It is mostly white or pale yellow-brown with red and black spots that warn predators it is unpalatable.
Source: Wikipedia
Where can I find this butterfly?
It lives in sunny mountain meadows of the Rocky Mountains from Yukon and Alaska down to New Mexico.
Source: Wikipedia
Why do some larvae die early in the season?
Because the host plant’s leaves are toxic from November to February, and early snow melt can cause eggs to hatch while the leaves are still poisonous.
Source: Wikipedia
Same family (Papilionidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Parnassius_smintheus
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.