The genus Halictus is a large assemblage of bee species in the family Halictidae. The genus is divided into 15 subgenera, some of dubious monophyly, containing over 200 species, primarily in the Northern Hemisphere (a few species occur in South America, Asia and Africa). Most species are black or dark brown, sometimes metallic greenish-tinted, with apical whitish abdominal bands on the terga (the related genus Lasioglossum, which is otherwise often similar in appearance, has the abdominal hair bands located basally, not apically). Many species in the genus are eusocial, with colony sizes range from very small (two to four bees) to large (>200). Nests are typically burrows in the soil, with several ovoid "cells" in which pollen mixed with nectar is provided as food for the developing larvae; a single egg is laid on a pollen mass, and the cell is sealed. In a few species, the cells are arranged in clusters resembling a honeycomb, but constructed of soil rather than beeswax. Like most ground-nesting bees, the brood cells are lined internally with a waterproofing secretion. A few species in the genus have extensive geographic distribution, such as Halictus rubicundus, which spans virtually the entire Holarctic region. Previously, Halictus ligatus was considered to range from Canada to Venezuela, including the Caribbean. However, genetic data show that there are at least three species previously considered within this one. One of them is restricted to Southeastern USA and the Caribbean, one is Central American, and true H. ligatus is found in northern and western North America. Common European species include Halictus quadricinctus and Halictus sexcinctus, as well as H. rubicundus. H. rubicundus is solitary at high altitudes and latitudes but has eusocial colonies in warmer areas. Species Species within this genus include: Halictus acrocephalus Blüthgen, 1926 Halictus adjikenticus Blüthgen, 1923 Halictus aegypticola Strand, 1909 Halictus aeneobrunneus Pérez, 1895 Halictus aerarius Smith, 1873 Halictus aestuans Ebmer, 1978 Halictus albozonatus Dours, 1872 Halictus alfkenellus Strand, 1909 Halictus argilos Ebmer, 2005 Halictus asperatus Bingham, 1898 Halictus asperulus Pérez, 1895 Halictus atripes Morawitz, 1893 Halictus atroviridis Cameron, 1906 Halictus bagirensis Blüthgen, 1936 Halictus balearicus Pérez, 1903 Halictus berlandi Blüthgen, 1936 Halictus beytueschebapensis Warncke, 1984 Halictus brunnescens (Eversmann, 1852) Halictus bucharicus Blüthgen, 1936 Halictus bulbiceps Blüthgen, 1929 Halictus caelestis Ebmer, 1976 Halictus carinthiacus Blüthgen, 1936 Halictus centaureae Ebmer, 1985 Halictus centrosus Vachal, 1910 Halictus cephalicus Morawitz, 1873 Halictus chalybaeus Friese, 1910 Halictus clangulus Warncke, 1984 Halictus cochlearitarsis