The first complete mitochondrial genome of the lacewing family Osmylidae (Thyridosmylus langii (McLachlan, 1870)) (Neuroptera) was sequenced in this study. The genome is a circular molecule of 16,221 bp containing the typical 37 genes but is arranged in the same order as that of the putative ancestor of hexapod and lacks translocation of trnC as shared by all previously sequenced neuropteran mtDNAs. This reveals that trnC translocation does not represent an organizational synapomorphy in the mitochondrion for the entire Neuroptera clade. Comparative analysis of neuropteran tRNA genes reveals a relatively slow and conserved evolution of the mitochondrion throughout the order. Secondary structure models of the ribosomal RNA genes of T. langii largely agree with those proposed for other insect orders. Nevertheless, domain I of T. langii rrnL is consisted of nine helices rather than eight helices which is typical for neuropteran rrnL. Protein-coding genes have typical mitochondrial start codons, with the exception of COI, which uses the TCG start codon also found in Ithonidae and Chrysopidae. Like other neuropteran insects, the control region is the most AT-rich region and comparatively simple, with little evidence of conserved blocks or long tandem repeats. Considering the issues of base-compositional and branch length heterogeneity, we used a range of phylogenetic approaches to recover neuropteridan relationships and explored the effect of method choice on recovery of monophyly of Neuropterida: ((Neuroptera + Megaloptera) + Raphidioptera). The monophyly of Neuroptera and the more basal position of Osmylidae were also recovered by different datasets and phylogenetic methods.

The first phylogeny of the lacewing family Osmylidae is presented here based on a total evidence analysis of DNA sequences for multiple gene loci and morphology for representatives of almost all extant genera. Our phylogeny shows a basal dichotomy in the family, with subfamilies Protosmylinae, Spilosmylinae and Gumillinae comprising one lineage, and the other lineage including Osmylinae, Porisminae, Eidoporisminae, Kempyninae and Stenosmylinae. The status of Paryphosmylus Krüger and Lysmus Navás as members of Protosmylinae is affirmed as well as the placement of Gumillinae near Protosmylinae and Spilosmylinae. Our results suggest that Porisminae, Eidoporisminae and Stenosmylinae evolved from a common ancestor, and their relationships, including likely paraphyly of Stenosmylinae, requires further assessment. Divergence time analysis revealed that the family originated during the Late Permian before the break‐up of the supercontinent Pangaea and that present generic distributions are not due to Gondwanan biogeographic events. All major subfamily‐level lineages were present by the end of the Triassic, in agreement with the rich Mesozoic‐aged fossil record for the family.

The first phylogenetic analysis of the genus Thyridosmylus Krüger is presented. All species from China were scored in a morphological analysis, along with extralimital species from India (Thyridosmylus pustulatus Kimmins) and Madagascar (Thyridosmylus marmoratus Fraser), and were compared with out-group exemplars from Spilosmylus Kolbe, Thaumatosmylus Krüger and Osmylus Latreille. A monophyletic Thyridosmylus sister to Spilosmylus is confirmed based on this analysis, with the Malagasy Thyridosmylus marmoratus as sister to the Oriental Thyridosmylus species. Based on the results of this analysis, the biogeography of world Thyridosmylus is discussed. It is proposed that the genus originated in Gondwana no later than the Late Cretaceous (88 Ma) before the break-up of the Madagascar-India continent. A new species, Thyridosmylus paralangii sp.n., is described from Guangxi Province, whereas two species [Thyridosmylus langii (McLachlan) and Thyridosmylus perspicillaris minor Kimmins] are recorded from China for the first time. Four synonyms are identified: Thyridosmylus laetus Yang et al. syn.n., Thyridosmylus similaminor Yang syn.n., Thyridosmylus vulgatus Yang syn.n. and Thyridosmylus mimoroides Yang syn.n. A key to the species of the world is provided.

The first complete mitochondrial genome of the family Hemerobiidae (Neuronema laminatum Tjeder, 1936) is sequenced in this study. The complete mitochondrial genome is a typical double-stranded circular molecule of 17,164 bp (GenBank accession number: KR078257) containing 37 typical animal mitochondrial gene and an A + T-rich region. The gene order is identical to that of the putative ancestral arrangement of insects and other lacewings. Thirteen protein-coding genes (PCGs) possessed common triplet initiation codons ATN and mostly terminate with TAN codons except for ND5 with a single T residue adjacent to a downstream tRNA gene. All the 22 tRNAs, ranging from 63 to 72 bp, can be folded into classic clover-leaf secondary structure except for tRNA(Ser(AGN)), in which the dihydrouridine (DHU) arm did not form a stable stem-loop structure. The control region is 2131 bp long with an A + T content of 87.4%. In the sampled families of Neuroptera, Osmylidae + the remaining families, Hemerobiidae + Mantispidae, Polystoechotidae + Rapismatidae, are recovered in phylogenetic analyses with high supports.

The genus Symbiopsocus is reviewed and S. furcatus sp. n., is described from China. The biogeography of 10 Chinese species is discussed briefly, and a distribution map provided. An updated key to the 13 world species is presented.