Illustrated keys to adults reflecting the current higher classification are provided for families of Cicadomorpha (cicadas, spittlebugs, leafhoppers, and treehoppers) and for subfamilies and tribes of Cicadellidae (leafhoppers), excluding Deltocephalinae. The following families (and superfamilies) are recognized: Cicadidae and Tettigarctidae (Cicadoidea); Aphrophoridae, Cercopidae, Clastopteridae, Epipygidae, and Machaerotidae (Cercopoidea); Aetalionidae, Cicadellidae, Melizoderidae, Membracidae, Myerslopiidae (Membracoidea). The higher classification of Cicadellidae is currently undergoing revision, but a provisional key to subfamilies and tribes (except Deltocephalinae) is provided. Two new synonymies are proposed: Signoretiinae Baker, 1915 equals Phlogisinae Linnavuori, 1979, new synonym; Iassini Walker, 1870, equals Hyalojassini Evans, 1972, new synonym.

A data set comprising DNA sequences from 388 loci and >99,000 aligned nucleotide positions, generated using anchored hybrid enrichment, was used to estimate relationships among 138 leafhoppers and treehoppers representative of all major lineages of Membracoidea, the most diverse superfamily of hemipteran insects. Phylogenetic analysis of the concatenated nucleotide sequence data set using maximum likelihood produced a tree with most branches receiving high support. A separate coalescent gene tree analysis of the same data generally recovered the same strongly supported clades but was less well resolved overall. Several nodes pertaining to relationships among leafhopper subfamilies currently recognized based on morphological criteria were separated by short internodes and received low support. Although various higher taxa were corroborated with improved branch support, relationships among some major lineages of Membracoidea are only somewhat more resolved than previously published phylogenies based on single gene regions or morphology. In agreement with previous studies, the present results indicate that leafhoppers (Cicadellidae) are paraphyletic with respect to the three recognized families of treehoppers (Aetalionidae, Melizoderidae, and Membracidae). Divergence time estimates indicate that most of the poorly resolved divergence events among major leafhopper lineages occurred during the lower to middle Cretaceous and that most modern leafhopper subfamilies, as well as the lineage comprising the three recognized families of treehoppers, also arose during the Cretaceous.

Previous phylogenetic analyses of the leafhopper family Cicadellidae based on morphological and molecular data suggested that Deltocephalinae, as traditionally defined, is polyphyletic. These analyses recovered a large clade comprising Deltocephalinae and several other subfamilies. To further elucidate relationships within this large clade of deltocephaline‐like leafhoppers, an expanded dataset of 119 morphological characters and 68 taxa was compiled and analysed using cladistic methods. The taxon sample included one or more representatives of nearly all previously recognised tribes of Deltocephalinae, representatives of the non‐deltocephaline family‐group taxa which grouped with Deltocephalinae in previous analyses, and six putative outgroup taxa drawn from other cicadellid subfamilies. The resulting most parsimonious trees consistently recovered the putative ingroup as monophyletic. However, in agreement with previous analyses, most subfamilies and tribes represented by multiple exemplars were not resolved as monophyletic groups. Based on these results, subfamilies derived from within the deltocephaline lineage include Acostemminae, Arrugadinae, Drakensbergeninae, Eupelicinae, Koebeliinae, Mukariinae, Paraboloponinae, Penthimiinae, Selenocephalinae and Stegelytrinae. The phylogeny indicates that grass specialisation is much more phylogenetically conservative than implied by the current higher classification of leafhoppers. A list of synapomorphies on the strict consensus tree and an illustrated key to all family‐group taxa of deltocephaline‐like leafhoppers are provided.