A review of the Augochloropsis (Hymenoptera, Halictidae) and keys to the shiny green Halictinae of the midwestern United States

Augochloropsis and other shiny green Halictinae have had various taxonomic issues and are often misidentified. One prevailing taxonomic issue is that Augochloropsismetallica (Fabricius) has two subspecies, that have long been recognized as morphologically distinct (Augochloropsismetallicametallica and Augochloropsismetallicafulgida (Smith), but the subspecies are inconsistently applied in the literature. Here, we review the Augochloropsis of the Midwest and further address the Augochloropsis species in the broader United States to resolve the outstanding taxonomic issues with the midwestern species. We provide identification keys and diagnoses for the genera and species of the shiny green Halictinae of the midwestern United States, which includes the genera Agapostemon, Augochlora, Augochlorella, and Augochloropsis. This work results in taxonomic changes to Augochloropsis. Augochloropsissumptuosa (Smith) is split into two species, with the name Augochloropsissumptuosa retained for the eastern form, and Augochloropsishumeralis (Patton), stat. nov., reinstated for the western form. Augochloropsismetallica is split into five species, with two of those species occurring in the midwestern United States: Augochloropsismetallica and Augochloropsisviridula (Smith), stat. nov. Examination of the holotype of Augochloropsisfulgida (Smith) revealed that it does not agree with the prevailing concept of Augochloropsismetallicafulgida; it is reinstated as Augochloropsisfulgida, stat. nov., but is currently known only from the holotype female from Florida. Augochloropsiscuprea (Smith), long considered to be a synonym of Augochloropsismetallica, is also distinct, and we are reinstating Augochloropsiscuprea, stat. nov., though the range of this species is unclear. We further recognize Augochloropsisfulvofimbriata (Friese), stat. nov., from South and Central America, as distinct. These changes result in a total of three Augochloropsis species in the Midwest and seven named species in the United States. We are aware of additional species from the southern and southwestern United States that are undescribed, and we highlight additional taxonomic work that remains to be done.