Gene rearrangement of the mitochondrial genome of insects, especially the rearrangement of protein-coding genes, has long been a hot topic for entomologists. Although mitochondrial gene rearrangement is common within Annulipalpia, protein-coding gene rearrangement is relatively rare. As the largest family in Annulipalpia, the available mitogenomes from Hydropsychidae Curtis, 1835 are scarce, and thus restrict our interpretation of the mitogenome characteristic. In this study, we obtained 19 novel mitogenomes of Hydropsychidae, of which the mitogenomes of the genus Arctopsyche are published for the first time. Coupled with published hydropsychid mitogenome, we analyzed the nucleotide composition evolutionary rates and gene rearrangements of the mitogenomes among subfamilies. As a result, we found two novel gene rearrangement patterns within Hydropsychidae, including rearrangement of protein-coding genes. Meanwhile, our results consider that the protein-coding gene arrangement of Potamyia can be interpreted by the tandem duplication/random loss (TDRL) model. In addition, the phylogenetic relationships within Hydropsychidae constructed by two strategies (Bayesian inference and maximum likelihood) strongly support the monophyly of Arctopscychinae, Diplectroninae, Hydropsychinae, and Macronematinae. Our study provides new insights into the mechanisms and patterns of mitogenome rearrangements in Hydropsychidae.

Adults and larvae of the genus Hydropsyche from Yun-nan and Si-chuan Provinces, China, were examined and the COI barcode gene sequences were obtained and analyzed, adults and larvae of 3 species were successfully associated. Of them, H. uvana Mey 1995 is a new record for the Chinese caddisfly fauna. The larvae of H. cerva Li & Tian 1990, H. penicillata Martynov 1931, and H. uvana Mey 1995 are described for the first time. The diagnostic features of the species are described and illustrated.

Fifty individuals of Limnephilus from the Qinghai Province, China, were examined, and their COI barcode sequences were extracted and analyzed. Forty individuals of Limnephilus from the Insect Collection of Nanjing Agricultural University (ICNAU), China, were examined, and photos of the male genitalia of four Limnephilus species are here presented. The males, females, larvae, and pupae of a new species, Limnephilus deqianensis n. sp., associated via COI barcode sequences, are described and illustrated. Ecological photos of the male, pupal case, and the habitat of the new species L. deqianensis n. sp. are also provided. Five species groups containing all seventeen Chinese Limnephilus species are revised. Diagnoses, keys, and a distribution map of them are provided. All of the sequences have been uploaded to GenBank. All specimens are deposited in the ICNAU, Nanjing, Jiangsu Province, P. R. China.

The male adult of Molanna truncata Ge, Peng & Sun sp. nov. is described and illustrated based on material collected in Si-chuan, China. It could be diagnosed by the subtriangular superior appendages when viewed dorsally, and by the mesal appendages each having a slender thorn and inferior appendages with a tiny inner process. Based on morphology of genitalia, we provide a dichotomous key to adult males of Molanna from the Oriental region. The DNA barcodes (partial mtCOI sequences) of M. truncatasp. nov. are generated and compared with existing sequences of Molanna species from Oriental and Palearctic regions. The mean intraspecific divergence of Molanna was 1.58% with a maximum of 8.50% in M. moesta. The Automatic Barcode Gap Discovery (ABGD) analysis of Molanna inferred 9 OTUs and thresholds of interspecific divergence of 10%. Divergence of M. truncatasp. nov. haplotypes from all other Molanna haplotypes ranged from 10.1% to 18%. We discuss distribution and potential groups of species within the Oriental Molanna species based on morphology.

Five new species of genus Tinodes Curtis 1834 from China are described, illustrated, and diagnosed based on distinctive characters of male genitalia, including Tinodes falcata n. sp., T. xuzhouorum n. sp., T. shunhuangshanensis n. sp., T. yangae n. sp., and T. lini n. sp. Tinodes falcata n. sp. differs from other members of Tinodes in having an unpaired falcate and strongly sclerotized phallic sheath process. Tinodes xuzhouorum n. sp. differs from T. charmi Malicky 2009 by the relative lengths of the superior appendages and the phallus, the position of the ejaculatory duct, and the angle formed by tergum IX and the superior appendages in lateral view. Tinodes shunhuangshanensis n. sp. can be distinguished from T. sartael Malicky 2017 by the phallic sheath process splitting into paired dorsal branches and an apically incised ventral branch. Tinodes yangae n. sp. differs from T. eris Malicky & Sangpradub 2001 by the dorsal phallic sheath process having extra paired vertical branches. Tinodes lini n. sp. differs from T. dactringa Johanson & Oláh 2008 by the phallic guide with a pair of closely attached dorsal branches.