Megachile (Chrysosarus) have black integument and can have reddish, tan, gray, or yellow hairs that often form apical bands on their terga (Michener 2007). They range in body length from 8–17 mm (Michener 2007).
Male Megachile (Chrysosarus) may be confused with bees in the subgenus Megachile (Zonomegachile) since they both have three-toothed mandibles, enlarged front tarsi, a spine on the fore coxa, and the T6 has a preapical carina with a strong median emargination (Michener 2007). Male M. (Chrysosarus), however, lack the strong hypostomal projection at the mandibular base that is present in M. (Zonomegachile). Female Megachile (Chrysosarus) can be differentiated from Megachile (Zonomegachile) by the lack of cutting edges on the mandible (Michener 2007).
Megachile (Chrysosarus) have been observed visiting the flowers of Asteraceae, Convolvulaceae, Fabaceae, Hydrophyllaceae, Lamiaceae, Lythraceae, Malvaceae, Onagraceae, Oxalidaceae, Passifloraceae, Ranunculaceae, Rubiaceae, Solanaceae, Verbenaceae, and Zygophyllaceae (Raw 2006; Raw 2007).
Megachile (Chrysosarus) nests are constructed out of chewed leaves in pre-existing cavities (Laroca 1971; Laroca et al. 1992; Zillikens and Steiner 2004). Brood cells differ from other Megachile subgenera in that they contain a layer of mud between layers of petals and leaves (Laroca et al. 1992; Raw 2007). Megachile (Chrysosarus) have been observed nesting in bamboo, bramble, wood, galls, trap nests, bromeliad leaves, the abandoned nests of digger bees (Centris) and potter wasps (Eumenidae), and in cane roofs of houses (Raw 2007).
Megachile (Chrysosarus) consists of fifty-six species (Raw 2007); none are known to occur in the U.S. or Canada.
There are no known invasives.
Megachile (Chrysosarus) occurs predominantly in South America where they are found in Guyana, Peru, Brazil, Paraguay, Argentina, and Panama (Raw 2007).