Ichneumonidae is one of the largest families of insects with a mega-diversity of specialized morphological and biological characteristics. We newly sequenced 92 mitochondrial genomes of ichneumonid wasps and found that they have a conserved base composition and a lower evolutionary rate than that of other families of parasitic Hymenoptera. There are 38 types of gene order in the ichneumonid mitochondrial genome, with 30 novel types identified in 104 ichneumonids. We also found that the rearrangement events occur more frequently in Ophioniformes than in Ichneumoniformes and Pimpliformes. Furthermore, the higher Ophioniformes and their relative lineages shared the transposition of trnL2 to trnI-trnQ-trnM tRNA cluster. We confirmed five higher-level groupings of Ichneumonidae: Brachycyrtiformes, Ichneumoniformes, Ophioniformes, Pimpliformes and Xoridiformes. Two formerly unplaced subfamilies, Eucerotinae and Microleptinae, were placed in Brachycyrtiformes and Ichneumoniformes, respectively. The results will improve our understanding of the diversity and evolution of Ichneumonidae.

Campopleginae, the third largest subfamily of Ichneumonidae, has been one of the most investigated ichneumonids from the perspective of biological control. Despite their importance as potential biological control agents, species of campoplegine are among the most poorly studied insect groups. In this study, one new species of the genus Lemophagus Townes, 1965, Lemophagus nanus sp. nov., is described and illustrated. In addition, L. curtus and L. pulcher are recorded from China for the first time.

We obtained four mitochondrial genomes of Odontocolon sp., Xorides funiuensis, Euceros kiushuensis and Euceros serricornis, which represent the first two representatives from subfamily Eucerotinae and Xoridinae (Ichneumonidae), respectively. All of the 4 newly sequenced mitochondrial genomes contain 13 protein-coding genes (PCGs) and most 24 RNA genes. Furthermore, they all have novel tRNA rearrangement patterns comparing with published mitogenomes in Ichneumonidae. For the tRNA cluster trnI-trnQ-trnM, X. funiuensis is shuffled as trnM-trnI-trnQ with trnQ inversed, while Odontocolon sp. with a remote translocation of trnK, shuffling as trnI-trnM-trnQ. E. kiushuensis and E. serricornis shared the same cluster trnQ-trnY-trnW-trnC. Finally, we reconstructed the phylogenetic relationships among the sequenced subfamilies of Ichneumonidae based on nucleotides and amino acids sequences of 13 PCGs in mitochondrial genomes, and the results of both the maximum likelihood and Bayesian inference analyses highly support that Eucerotinae is the basal ichneumonid lineage rather than Xoridinae.

DNA barcoding is an effective modern tool in taxonomy, evolutionary biology, and biodiversity research. Many new species have been discovered and described with DNA barcodes as part of their diagnostic features. We combined morphological examination and molecular species delimitation of the mitochondrial cytochrome c oxidase 1 (COI) gene using the automatic barcode gap discovery (ABGD) to investigate species boundaries. The genus Prochas Walkley (Hymenoptera, Ichneumonidae, Campopleginae) was first reported from China and is new for the Oriental and Eastern Palearctic regions. Using an integrative taxonomy method, two new species P. rugipunctata sp. nov. and P. striata sp. nov. are hereby described and illustrated. A key to the world species and a distribution map are provided.

Four new species ofVenturiaSchrottky, 1902 (Hymenoptera, Ichneumonidae, Campopleginae) from Oriental China and Nepal are described (V. contiguussp. nov.andV. yunnanensissp. nov.from China;V. liuaesp. nov.andV. levocarinatasp. nov.from Nepal). In addition, two species are reported from China (V. serpentinaMaheshwary, 1977 andV. inclyta(Morley, 1923)) for the first time and all listed species are illustrated. A key to all species from China and Nepal is provided.