Megachile (Rhyssomegachile)

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Megachilini
Genus: Megachile Latreille, 1802
Subgenus: Rhyssomegachile Michener, 1965
Common name: none

Overview

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).

Diagnostic characteristics

(modified from Gonzalez et al. 2018)

Preoccipital carina strong laterally.
Scutum with punctures densely and coarsely punctate.
Female mandible four-toothed, with the innermost tooth truncate and incised, sometimes giving the appearance of being five-toothed.
Female mandible with cutting edges present, but incomplete and small so they can be difficult to see, in the second and third interspaces.
Female T6 straight in profile.
Male front coxa without spine.
Male tibial spurs present on the middle legs.
Male mandible three-toothed.
Male mandible without basal projection on lower margin.
Male T6 with preapical carina strong and medially emarginate with a shallow emargination and a small, lateral tooth on the posterior margin.

May be confused with

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).