Other Common Names
Often cited as "Redbelted" Bumble Bee, but use of a hyphen is generally preferred when citing common names (see AOU and BOU bird checklists).
Explanation of Names
Common name refers to the reddish band across the abdomen.
Author: Cresson, 1863.
queen: body length 16-18 mm
worker: 11-12.5. Workers are often notably small.
Those with red on the metasoma are often confused with various Pyrobombus whereas those without can be confused with Bombus bimaculatus and various other species, but in rufocinctus the malar space is exceptionally short.
In females with red on the metasoma the red is on the apicolateral corners of T2 and on T3 and T4, with T1 and most of T2 yellow, whereas in species such as ternarius and huntii T2-T3 are entirely red and T4 is yellow. Bombus centralis can be confusing in that its metasoma is yellow basally and red apically, but in that species T2 is entirely yellow and the facial hairs are all yellow (also usually true of huntii and bifarius but not ternarius, sylvicola, or rufocinctus). The dorsum of the scutum has black as in other species, but this is often a rather diffuse blotch as opposed to a narrow, well-defined interalar band (as in huntii) or clearly extending to form a notch in the scutellum posteriorly (as in bifarius and to a lesser degree ternarius). However, rufocinctus females can have a complete, broad interalar band.
The female castes can differ in color of facial hairs as this is often yellow in queens but mostly black in workers.
Males have large eyes and are relatively small. Those with red on T3-T4 are distinctive but those without can be confused with griseocollis (not black corners on T2 in most of those) and nevadensis (note yellow on T3 in that species). Antennal proportions are quite helpful. The eyes are less closely approximated above than in nevadensis.
see detailed description of queen, worker, male at discoverlife.org
Transcontinental. Best known at northern sites and in the western mountains. Very local in occurrence in the northeastern United States but locally numerous at some sites, such as near Albany, New York. Some surprising, disjunct records are known from New York and also New Jersey (J. S. Ascher, unpublished).
Typical open sites, especially prairies, but also mountain meadows and sometimes unusual places such as quarries or pine barrens. Not generally distributed and seems to avoid cities.
The Hosts section of its Discover Life species page
lists known associations based on specimen records and images.
page creation based on John S. Ascher's identification of this image
18 pinned adult images
plus detailed description of queen, worker, male, distribution, seasonality (discoverlife.org)
common name reference; PDF doc
(Committee on Common Names of Insects, Entomological Society of America)