Queen and Worker:
Head: Black. Worker has some yellow on back of head.
Thorax: Dense, short yellow hairs, including the sides right down to the legs. Centre with bare elongated spot, small with a few short black hairs.
Wings: Uniformly black with brown to blackish veins. Worker wings lighter.
Legs: Hair on legs very short, entirely black.
Abdomen: Segment 1 is yellow. Segment 2 is more yellow on queen; yellowish-brown on worker; the yellow is restricted to center of segment with curved side edges extending up along base of segment. Segments 3 to 5 black.
Head: Face has pale yellow hairs all over with a few black hairs intermixed on the top of the head. Face is narrow, huge eyes.
Thorax: Dense, short pale yellow hairs with small, central circular area grey to black hairs. Thorax sides all yellow.
Wings: Darkly tinted, veins yellowish-brown.
Legs: Fringe on thighs (femora) long and yellow. Lower legs have long, dark grey or black fringe. Abdomen: Segment 1 yellow. Segment 2 is yellow-brown at centre, the yellow-brown side edges curving out and extending along the base of the segment. Segments 3 to 6 are black.
Similar Species: Two Spotted Bumblebee Bombus bimaculatus has side edges of yellow on segment 2 straight up and down, not curved, queen and worker have yellow on top of head.
Size: Queen 20 to 22 mm. Worker 13.5 to 18 mm. Male 15 to 19 mm.
Habitat: Meadows, forest edges, nesting in dry soils above the ground.
Food: Generalist pollen and nectar feeder from a wide variety of flowers.
Flight Time: Mid-April to late September.
Life Cycle: Nest can have about 35 workers. Workers are very aggressive in defence of the colony. Males share in the brood care by warming pupae. They are often found with worn wings.
Comments: Essex County only in Leamington and Wheatley after 1980. In Colchester, Kingsville, Point Pelee and Pelee Island before 1980 per Colla. Common in rest of Ontario.