Extracted from 2017 “Bees of Maryland: A Field Guide” http://bio2.elmira.edu/fieldbio/beesofmarylandbookversion1.pdf
Familiar to many people for their habit of nesting in the soft woods of houses, benches, decks, and outbuildings, but often confused with Bumble Bees.
Field Marks: ♀♂Uniformly large, Bumble Bee-like. Face with only dark hairs. Thorax covered in dense off-white hairs. Abdomen, first segment with narrow fringe of pale hairs at the base, rest with sparse, short dark hairs. Abdomen shiny because dark hairs are generally sparse enough that glossy, weakly bluish, integument shows beneath. Face round, equally wide or wider than length. Unique, but difficult to see in the field, the marginal cell is 7X long as wide. Wings dark, but not opaque. ♀Face, between the antennae, has a small, but sometimes noticeable, projecting semicircular mound like the edge of a buried Frisbee. ♂Face, below antennae almost entirely creamy white. Eyes large compared to those of female and most bee species, nearly meeting together at top of head.
Flight Season: Throughout.
Size Relative to Honey Bee: 1.5X.
Position of Wings Feeding on Flowers: Held at 45° to body.
Location of Pollen Carrying Hairs: Hind femur, tibia, basitarsus.
Similar Genera: Bombus - Holds wings to it sides or across its back. Abdomen, hairs, except in old individuals, dense, hiding surface, many species; many species have extensive yellow/pale hair beyond the first segments. Face long, longer than wide. Workers smaller than Xylocopa. ♀Hind tibia, wide and bare in center, carry large, noticeable mixed masses of pollen/nectar (rare species are parasitic and look like males), Xylocopa never have large masses of pollen on their legs, pollen usually hidden among hairs. ♂Face entirely black though may have yellow hairs. B. griseocollis/B. auricomus has round face/ large eyes similar to Xylocopa but no white on face. Ptilothrix - Legs much longer. Wings held across back. Overall narrower. Feeds mostly on rosemallow (Hibiscus spp.). Hair on thorax lacks central bare spot of Xylocopa. ♂ No white on face. Anthophora - Smaller. Uncommon. Abdomen often with extensive pale hair. Wings held folded over back. ♀Head, top, flattened, evenly rounded in Xylocopa. ♂Eyes not larger than females and do not nearly meet at top of head. Abdomen, pale hairs more extensive.
Nest: Excavates short tunnels in soft wood, often in man-made structures.
Flowers: Uses a variety of large, tall forbs and woody plants.
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