Megachile (Rhyssomegachile) are medium-sized bees with overall black integument, sometimes with reddish-brown coloration on the mandible, legs, tegula, and sterna. They often have white apical hair bands on the terga and can range in body length from 8–12 mm (Gonzalez et al. 2018).
(modified from Gonzalez et al. 2018)
Megachile (Rhyssomegachile) may be confused with bees within the subgenera M. (Aporiochile), M. (Ptilosarus), and M. (Austromegachile) because they all have a strong preoccipital carina behind the gena (Gonzalez et al. 2018). M. (Rhyssomegachile) females can be differentiated these other subgenera by the lack of white fasciae beneath the scopa and incomplete cutting edge on the third interspace. Further, males can be separated by the lack of a spine on the front coxa and the strong preapical carina on T6 (Michener 2007; Gonzalez et al. 2018).
Floral associations are unknown.
Nesting behavior is unknown.
Megachile (Rhyssomegachile) consists of four species (Gonzalez et al. 2018); none are known to occur in the U.S. or Canada.
There are no known invasives.
Megachile (Rhyssomegachile) are known only from South America and have been collected from Columbia to southern Brazil (Gonzalez et al. 2018).