Eupolyphaga Chopard, 1929 is a cockroach genus mainly endemic to China. In this study, the species diversity of this genus is further explored through morphology and molecular analysis. Four species are described new to science: Eupolyphaga miracidia Qiu, sp. nov., Eupolyphaga udenostyla Qiu, sp. nov., Eupolyphaga reducta Qiu, sp. nov., and Eupolyphaga simila Qiu, sp. nov. New knowledge on some known species is added, including new distribution records and characteristics of females. Forty-five COI sequences were newly sequenced and a molecular species delimitation analysis was performed using ABGD method. Eighteen molecular operational taxonomic units were obtained by ABGD analysis, which are nearly consistent with the results of morphological delimitation.

We collected Ectobiidae cockroach specimens from 44 locations in the south of the Yangtze valley. We obtained 297 COI sequences specimens and carried out phylogenetic and divergence dating analyses, as well as species delimitation analysis using a General Mixed Yule Coalescent (GMYC) framework. The intraspecific and interspecific sequence divergence in Ectobiidae cockroaches ranged from 0.0 to 7.0% and 4.6 to 30.8%, respectively. GMYC analysis resulted in 53 (confidence interval: 37–65) entities (likelihood ratio = 103.63) including 14 downloaded species. The COI GMYC groups partly corresponded to the ectobiid species and 52 ectobiid species were delimited successfully based on the combination of GMYC result with morphological information. We used the molecular data and 6 cockroach fossil calibrations to obtain a preliminary estimate of the timescale of ectobiid evolution. The major subfamilies in the group were found to have diverged between ~125–110 Ma, and morphospecies pairs were found to have diverged ~10 or more Ma.

The genusCyrtonotulaUvarov, 1939 (Blaberidae, Epilamprinae) is recorded for the first time from Hainan Island, China. Three new species,Cyrtonotula epunctataWang & Wang,sp. nov.,C. maculosaWang & Wang,sp. nov., andC. longialataWang & Wang,sp. nov., are described based on morphological data and a molecular analysis using Automatic Barcode Gap Discovery (ABGD). Additional barcode data of blaberid species, including these three new species, are provided to facilitate future species identification. Morphological photographs and habitat photos of these new species, as well as a key to the known species, are provided.

In this study, we examine 500 specimens of Anaplecta collected from China, of which 26 samples were used for COI sequencing. We confirm eight new species, i.e., Anaplecta corneola Deng & Che sp. nov., Anaplecta staminiformis Deng & Che sp. nov., Anaplecta arcuata Deng & Che sp. nov., Anaplecta strigata Deng & Che sp. nov., Anaplecta furcata Deng & Che sp. nov., Anaplecta cruciata Deng & Che sp. nov., Anaplecta nigra Deng & Che sp. nov. and Anaplecta bicolor Deng & Che sp. nov. based on morphological and molecular data using ABGD and GMYC analyses. The results of ABGD and GMYC were basically consistent with the morphospecies of Anaplecta. The intraspecific and interspecific genetic distances of Anaplecta ranged from 0 to 6.6% and 16.8% to 31.8%, respectively. We found the male genitalia of Anaplecta to exhibit intraspecific variation, especially in the phallomeres.