Species of Dicyphus (Dicyphus) (Insecta: Heteroptera: Miridae: Bryocorinae: Dicyphini) are routinely used as biocontrol agents of vegetable crop pests in the Northern Hemisphere. However, they are notoriously difficult to identify. In response, we employed an integrative approach, combining molecular, morphometrics and morphological data, for the delimitation of species. Sequences of three mitochondrial genes (COI, 16S and 12S) for 15 putative Dicyphus (Dicyphus) species were analysed using phylogenetic and genetic methods. Morphometric data were analysed using PCA and Ctree analyses to test their previous use in species differentiation. External and male genitalia morphology were re-examined as an additional partition for testing species boundaries. Twenty-one Dicyphus (Dicyphus) species, based on genetic distances >1%, external and male genitalic characters were determined. The subgenus and all of the included species are diagnosed, and previously recognized species that we determined as valid are redescribed. The following new synonyms are proposed: D. marocannus Wagner and D. bolivari altanticus Wagner are synonymized with D. bolivari Lindberg; D. umbertae Sanchez and Cassis is synonymized with D. cerastii Wagner; and, D. baezi Ribes is synonymized with D. rubicundus Blote. Two new species from Spain (D. argensis sp. nov.) and Turkey (D. caycumensis sp. nov.) are described.
