Bumble Bees of Montana
Bombus (Pyrobombus) frigidus Smith, 1854 Frigid Bumble Bee
Bombus frigidus is known to inhabit the tundra/taiga and boreal regions of North America, from eastern Canada west to Alaska and in the mountains of the western U.S. to Oregon and Colorado (Williams et al. 2014). In Montana, it has been collected in the mountains of the western counties, in the foothills of Golden Valley County, and in the Little Rocky Mountains of Blaine County.
Recorded Montana Distribution
Bombus frigidus has a cheek that is approximately as long as it is wide. Its body hairs are long and uneven, the hairs on the face are black, and the hairs on the thorax in front of the wings are yellow without black intermixed. Abdominal T2 is yellow without black hairs laterally and T5 (and often T4) is orange.
This species is most easily confused with B. mixtus and B. kirbiellus. Bombus mixtus has many black hairs intermixed with the yellow on the thorax in front of the wings. Also, B. mixtus usually has black hairs on the sides of T2 and often has orange hairs on T3. Bombus kirbiellus has a color pattern very similar to B. frigidus, but has an obviously longer-than-wide cheek.