Synonyms and other taxonomic changes
Bombus occidentalis of western North America has often been treated as a subspecies of Bombus terricola but is now most often regarded as distinct.
queen: body length 17-19 mm
male: 13-17 mm
worker: 9-14 mm
for detailed descriptions of queen and male; worker resembles queen in general, but pubescence relatively longer
northern and eastern North America? Most records from the Rocky Mountains of the USA mapped in the Williams et al. guide surely pertain to misidentified occidentalis.
The Hosts section of its Discover Life species page
lists known associations based on specimen records and images.
Declines of this species were first noted by John S. Ascher at Ithaca, New York, ca. 2001. In the 1990s this was one of the most common bumble bees in that region, but afterwards few individuals were detected. The species persists in relatively large numbers at some sites, especially in the northern portion of its range, but it has undoubtedly declined severely.
24 pinned adult images
plus detailed description of queen, worker, male, distribution, seasonality, flower records, similar species (discoverlife.org)
discussion of taxonomic status
(Paul Williams, Natural History Museum, UK)
common name reference; PDF doc
[Yellowbanded Bumble Bee] (Committee on Common Names of Insects, Entomological Society of America)
IUCN Red List
(Vulnerable listing with explanation)