A revision of the Encarsia mexicana species-group (= Dirphys Howard) (Hymenoptera: Aphelinidae), gregarious endoparasitoids of whiteflies (Hemiptera: Aleyrodidae) in the Neotropical Region.

The genus Howard 1914 is synonymized with Förster, and treated as a species-group of , referred to henceforth as the species-group. The monophyly of is discussed in relation to . The new synonymy is based on phylogenetic analyses of the nuclear ribosomal 28S-D2 gene region (43 taxa, 510 bp). The species-group is recovered as strongly monophyletic within All species of the species-group are revised. The group includes six previously described species, and fourteen newly described species. All species are described (or redescribed) and illustrated. Detailed distributional data, and, where available, plant associate and host records are provided for all species. Kresslein and Polaszek is here proposed as a replacement name for Myartseva, now preoccupied by (Howard). A dichotomous identification key, supplemented by an online multiple-entry key, is provided for all species.