The clade Argidae + Pergidae is invariably retrieved as the sister group to Cimbicidae. The combined ‘CAP’ clade is supported by the absence of a postscutellum (char. 49:0; reversed in some Pergidae, paralleled in some Diprionidae), the cenchrus not being inflected posteriorly (char. 64:1; paralleled in Diprionidae), the metapleuron being fused dorsally with the lateral margins of tergum 1 (char. 69:1, Fig. 11B–D), the absence of the posteroventral metapleural apodeme and the associated posterior metapleuro‐furcal muscle (char. 70:0), and tergum 1 being continuous medially [char. 114:1 (Figs 10C, D and 17); some reversals, e.g. in Brasilabia (Fig. 10A)]. The CAP clade has been retrieved by other morphological analyses (e.g. Vilhelmsen, 2001, 2015), but not by molecular or combined analyses, which have placed Cimbicidae as sister to Diprionidae (Schulmeister, 2003; Schmidt & Walter, 2014; Isaka & Sato, 2015; Malm & Nyman, 2015) or a clade including Diprionidae (Heraty et al., 2011; Ronquist et al., 2012; Klopfstein et al., 2013). These studies all have very incomplete sampling of Cimbicidae; Malm & Nyman (2015) which otherwise has the most comprehensive sample of the family (five genera, eight species) did not include any South American cimbicids.