Planidia are free-living, mobile first-instar larvae that are notable in their ability to transition on a single host between different larval stadia, and for completing their development on the host prepupa as ectoparasitoids, effectively acting as larval-pupal external koinobionts. Within Chalcidoidea, a mega-diverse superfamily of parasitoid wasps, taxa with a planidium form a monophyletic group, the Planidial-Larva-Clade (PLC), which has been comprised of three recognized groups: Eutrichosomatinae (Pteromalidae), Perilampidae (Chrysolampinae, Perilampinae, Philomidinae and the unplaced genus Jambiya), and Eucharitidae (Akapalinae, Eucharitinae, Gollumiellinae and Oraseminae). To clarify the classification and better understand the evolution of this clade, we conducted a phylogenomic study of the PLC using anchored hybrid enrichment data. The phylogenetic analyses support the backbone relationship of PLC as: (Eutrichosomatinae, ((Philomidinae, Chrysolampinae), (Perilampinae, Eucharitidae))). Although excluded from the main analyses, the genus Jambiya, based on only 11 loci recovered, was placed as the sister of Chrysolampinae + Philomidinae or Perilampinae + Eucharitidae. Our results support the placement of Eutrichosomatinae at the base of the PLC phylogeny and demonstrate that Perilampidae (Philomidinae, Chrysolampinae and Perilampinae) are paraphyletic. In contrast to other studies, anchored enrichment data fail to recover the Ponerinae- Ectatomminae-Myrmeciinae (PEM) parasitoid clade within Eucharitinae, which may indicate a more complicated evolutionary history of ant-host shifts. Traits explored using Likelihood Ancestral State Reconstruction include the evolution of host associations, direct versus indirect hyperparasitism, ability to attack a host within a cocoon, soft versus hard planidial forms, and mobility of the planidium. Divergence dating based on four calibration fossils suggests that the planidial clade arose approximately 111 Ma and the evolution of ant parasitism at least 64 Ma. A revised higher-level classification of the planidial larva clade is proposed with Eutrichosomatinae elevated to Eutrichosomatidae (Rev. Stat.), Chrysolampinae and Philomidinae placed in Chrysolampidae (Rev. Stat.), Perilampidae (Rev. Stat.) restricted to what was referred to as Perilampinae, and Eucharitidae maintained with four subfamilies, with Akapalinae (unknown biology) as sister group to the core Eucharitidae, all of which are ant parasitoids. Jambiya is treated as an incertae sedis taxon within the planidial clade.