Bug FAQWestern Poplar Sphinx
Pachysphinx occidentalis · Order: Lepidoptera · Family: Sphingidae
Also called: Big Poplar Sphinx Moth, Western Poplar Sphinx Moth
The western poplar sphinx has a wingspan of about 130 to 150 mm and comes in a pale yellow-brown form or a darker gray form, both with clear lines and a variable crimson patch on the hindwing. It lives in riparian zones and suburban areas across Canada and the United States, where its larvae feed on cottonwood (Populus) and willow (Salix) trees. In southern Arizona there are two generations each year with adults on the wing from May to September, while farther north there is one generation with adults from June to August.
Source: Wikipedia
How to recognize it
The wing patterns have well-defined lines and bands, and the hindwing upperside shows a crimson patch of varying size plus two dark lines that do not make a distinct triangle.
Source: Wikipedia
Size
The wingspan ranges from 130 to 150 mm.
Source: Wikipedia
Where it lives
It inhabits riparian areas and suburban environments.
Source: Wikipedia
What it eats
The caterpillars feed on cottonwood (Populus) and willow (Salix) species.
Source: Wikipedia
Life cycle
In southern Arizona there are two generations per year, with adults flying from May to September.
Source: Wikipedia
When you see it
Adults are active May-September in southern Arizona and June-August farther north.
Source: Wikipedia
Where it comes from
It is found throughout Canada and the United States.
Source: Wikipedia
Where it is found in the US
Recorded in 17 of 51 states and DC. Most records: Arizona, New Mexico, California, Colorado, Utah, Texas, Nevada, Oregon.
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
How many generations does the western poplar sphinx have each year?
In southern Arizona it has two generations per year, while farther north it has one generation per year.
Source: Wikipedia
When are adult western poplar sphinx moths active?
Adults are on the wing from May to September in southern Arizona and from June to August in more northern areas.
Source: Wikipedia
What do the larvae of the western poplar sphinx eat?
The caterpillars feed on cottonwood (Populus) and willow (Salix) trees.
Source: Wikipedia
Where can I find western poplar sphinx moths?
They live in riparian zones and suburban habitats across Canada and the United States.
Source: Wikipedia
Same family (Sphingidae)
White-lined SphinxHyles lineataDamages trees, gardens or crops
Eurasian Hummingbird HawkmothMacroglossum stellatarum
Snowberry ClearwingHemaris diffinis
Carolina SphinxManduca sextaDamages trees, gardens or crops
Hummingbird ClearwingHemaris thysbeDamages trees, gardens or crops
Elephant HawkmothDeilephila elpenorSources
- Wikipedia: https://en.wikipedia.org/wiki/Pachysphinx_occidentalis
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.