Handbook of Nearctic Chalcidoidea

If you know what a nearctic chalcid is and need help identifying them, then this guide is for you. For everyone else, a chalcid wasp gets its name from khalkos, which means "copper" in Greek and refers to their metallic color.

Over 150,000 species of Hymenoptera (bees, wasps, and ants) have been identified, with many 10s to 100s of thousands yet to be found or described. Wasps are a suborder of this group, which are then broken down into 14+ super-families. Chalcidoidea is one of these super-families and contains 22,000 known species and could contain up to 500,000 if all the different species were to be found and described. 

Nearctic refers to those chalcids that live in North America and this guide by HymAToL.org (Hymenoptera -- Assembling the Tree of Life) helps with identifying this group of insects.