Extracted from Jonathan Koch, James Strange,Paul Williams.2012. Bumble Bees of the Western United States. A product of the U.S. Forest Service and the Pollinator Partnership
with funding from the National Fish and Wildlife Foundation|
Select food plant genera: Chamerion, Lupinus, Geranium,
Symphoricarpos, Trifolium, Achillea
Tongue Length: Medium
Distribution: Northern Intermountain West and high elevation
Rockies; few records in eastern U.S
Can be confused with B. mixtus and B. balteatus
Females (queens and workers, colors refer to ‘hair’)
Thorax and T1-2 predominantly yellow, with a
black band between the wing bases, sides of the
thorax yellow, T4 orange at least apically, T5 orange
occasionally faded to yellow.
Mid leg basitarsus with the distal posterior corner
rounded. Cheek as long as broad. Hair of the face
black or with some yellow hairs, corbicular fringes
extensively pale orange. T2 anterio-laterally without
scattered black hairs intermixed. Hair length long.
Extracted from: Laverty T.M., & Harder L.D., (1988). The Bumble Bees of Eastern Canada. Can. Ent. 120: 965-987.
Description. Body size of all castes small to medium. Head rounded; malar space square in female, longer than wide in male. Tongue short. Individuals from tundra and forest tundra have typical B. frigidus colouration (Fig. 8a and c) with bright yellow pile on thorax and TI-T2, and red pile on T5-T6. Specimens from southern localities (originally described as B. couperi) have much duller yellow pile on thorax and T5 (Fig. 8b and 4. Most of these individuals can be separated from B. sandersoni by their distinct interalar spot or band and presence of yellow pile on T5.