Characters common to the family include:
- Glossa elongate; galeal and spitial combs absent
- One subantennal suture below each antenna
- Episternal groove absent except in the tribe Fideliini- Basitibial plate absent
- Forewing with 2 submarginal cells except 3 cells in the tribe Fideliini- Metasomal scopa is the primary pollen carrying location
There are 2 subfamilies: Fideliinae and Megachilinae.
Separated as:
Fideliinae - Forewing with 3 submarginal cells (except 2 in Fideliini); mandible either simple or with a single tooth; T6 with a pygidial plate
Megachilinae - Forewing with 2 submarginal cells; mandible with 3 or more teeth; T6 without a pygidial plate
There are 6 tribes as: Pararhophitini, Fideliini, Lithurgini, Anthidiini, Megachilini and Osmiini.
Source: Michener (2007). Bees of the World. John Hopkins University Press
