Abstract
The logical basis of identification keys and the principles underlying character selection are briefly discussed. The key is dichotomous in form and is intended to identify all known Chalcidoidea species to family, or in some cases to a lower level incertae sedis taxon. A set of shortcuts is provided to direct users to major branch points in the key. The key itself is composed of 116 couplets, divided into 11 sections: Part 1: Divergent and early-branching groups; Part 2: Most taxa with 4 or fewer tarsomeres; Part 3: Species with 5 tarsomeres (at least in fore and hind legs); Part 3.1: Acropleuron expanded; Part 3.2: Metafemur with ventral teeth; Part 3.3: Antenna with 8 or fewer flagellomeres; Part 3.4: Eyes ventrally divergent; Part 3.5: Antenna with 10 or fewer flagellomeres; Part 3.6: Generalized taxa with 11 or 12 flagellomeres in some members; Part 3.6.1: Occipital carina always present; and Part 3.6.2: Occipital carina either absent or present. Each couplet is illustrated with figure embedded directly in the body of the key.