SeasonalityFlight period of queens ranges from late April to early September; workers: early May to early September; males: early May to early October (Thorp et al., 1983).
IdentificationBombus centralis belongs to the diverse subgenus Pyrobombus Dalla Torre which is characterized by a malar space of medium length but longer than its apical width and antennal flagellum 2.5 to 3x the length of the scape. The penis valves of the males are usually hook shaped (Thorp et al., 1983).
Bombus centralis has a large, densely yellow haired body with a distinct black band between the bases of the wings. Females have reddish-orange pile on third and fourth abdominal segments (Curry 1984) while males have reddish pile on abdominal segments 3 thru 5 (Thorp et al. 1983). Pile at the base of the legs is often light (Franklin 1912). Body size and wingspan varies between castes: queens are 12.5 to 16 mm with wingspans of 29 to 33 mm, workers range between 9.5 to 12.5 mm with wingspans of 23 to 28 mm, and males are 10 to 13 mm with wingspans of 22 to 29 mm. Wings are lightly stained brown in all castes (Franklin 1912). Male genitalia are similar to B. flavifrons with smoothly rounded, sickle shaped penis valves, narrow valsellae and a weakly trilobate sternite 8 that is apically membraneous (Thorp et al. 1983, Franklin 1912).