About Bombus bifarius Cresson, 1879
Description and identification: Bombus bifarius has a relatively small body. For workers, body length ranges from 8 to 14 mm (0.31 to 0.55 in), and for queens it ranges from 15 to 19 mm (0.59 to 0.75 in). Their entire bodies are covered in short, even hair. The hair on the faces of B. bifarius individuals is usually yellow or white, and the top of the head sometimes has black coloration. Black coloration is also present on at least the lowest third of the thorax. The hindlegs and pollen baskets are brownish-orange, and the hairs on the second and third metasomal tergites are red. Distribution: Bombus bifarius occurs in mountainous regions of western North America, and is specifically limited to northern Arizona, Colorado, northern New Mexico, Utah, and southern Wyoming. All populations that were formerly classified as B. bifarius in other areas actually belong to the species B. vancouverensis instead.
