Bombus perplexus is medium-tongued bumble bee species with long dark yellow or light orange hairs. Gynes emerge from hibernation approximately in mid-May, then establish a nest belowground in abandoned mouse nests or rodent burrows. Workers begin emerging in early or mid-June, males mid- or late-July, and gynes at the end of July or early August.
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Generally, Bombus perplexus is a northerly species, occurring in the northern two-thirds of Minnesota. It is infrequently observed in the Twin Cities metropolitan area. Aptly named, the confusing (or perplexing) bumble bee has multiple and variable color patterns. Consistent features include the thorax with long dark yellow or light orange hairs, usually lacking any dark hairs or defined spot. On females, dark hairs occur on the side of the thorax, below the wing bases. For males and females, the abdomen has yellow hairs on the first through third tergites (T1-T3), and for males, occasionally on the fourth tergite (T4). Females can have white hairs on the apex of T5 and part of T6, males on T7. For males, the third flagellum is three times as long as the scape, and the eyes are similarly-sized as females (not enlarged like some other male Bombus species). Both males and females have yellow hairs on the face and yellow hairs on the vertex.