Overview
The Halictidae are recognised as a subfamily of Apidae in Michener (2000) and in the Lucid identification key on this website.
The following text is from Naumann (1991).
A large cosmopolitan family of minute to moderate-sized bees, usually black, often at least partly metallic green or blue, and frequently with their abdomen orange-brown. Pubescence is moderately abundant (except in the parasitic
Sphecodes
) and usually forms a pollen-carrying scopa on the hind leg from coxa to basitarsus and sometimes also on adjacent parts of the body. However, in
Homalictus
the scopa is chiefly confined to the underside of the metasoma.
Further information about the Apidae can be found in Melo & Goncalves 2005, Michener 1965, Michener 2000 and Naumann 1991.