House flies (Muscidae) comprise the most species-rich family of the muscoid grade with over 5000 described species worldwide, and they are abundant in various terrestrial and aquatic ecosystems. The high number of species, varied appearances, complex feeding habits, and wide distributions have hindered researchers from understanding their phylogeny and evolutionary history. Here, we newly sequenced fifteen mitochondrial genomes and reconstructed the phylogenetic relationships and divergence time among eight subfamilies of Muscidae (Diptera). The best phylogenetic tree, which was inferred by IQ-Tree, recovered the monophyly for seven out of eight subfamilies (except for Mydaeinae). Based on phylogenetic analyses and morphological characteristics, we prefer the subfamily status of Azeliinae and Reinwardtiinae, and separate Stomoxyinae from Muscinae. Genus Helina Robineau-Desvoidy, 1830 was synonymized with Phaonia Robineau-Desvoidy, 1830. The divergence time estimation indicated Muscidae originated at 51.59 Ma (early Eocene). Most subfamilies had originated around 41 Ma. We provided a mtgenomic viewpoint on the phylogenetic relationships and divergence time estimation of Muscidae.

Chloropidae, commonly known as grass flies, represent the most taxonomically diverse family of Diptera Carnoidea, comprising over 3000 described species worldwide. Previous phylogenetic studies of this family have predominantly relied on morphological characters, with mitochondrial genomes being reported in a few species. This study presents 11 newly sequenced mitochondrial genomes (10 Chloropidae and 1 Milichiidae) and provides the first comprehensive comparative analysis of mitochondrial genomes for Chloropidae. Apart from 37 standard genes and the control region, three conserved intergenic sequences across Diptera Cyclorrhapha were identified in all available chloropid mitochondrial genomes. Evolutionary rates within Chloropidae exhibit significant variation across subfamilies, with Chloropinae displaying higher rates than the other three subfamilies. Phylogenetic relationships based on mitochondrial genomes were inferred using maximum likelihood and Bayesian methods. The monophyly of Chloropidae and all four subfamilies is consistently strongly supported, while subfamily relationships within Chloropidae remain poorly resolved, possibly due to rapid evolution.

The known species of the genus Norellisoma from China are reviewed and two new species from Yintiaoling Nature Reserve in Chongqing City, where no other Norellisoma species are recorded, are described: Norellisoma wuxiense sp. nov., Norellisoma yintiaoense sp. nov. A key to the species of Norellisoma from China is provided.

The genus Anatrichus Loew, 1860 belongs to the subfamily Oscinellinae of the family Chloropidae. We report the complete mitogenome of Anatrichus pygmaeus as the new representative of the subfamily Oscinellinae. The complete mitochondrial genome was 17,125 bp in length. It consisted of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a control region. The phylogenetic result showed that the family Chloropidae is monophyletic, and the subfamily Chloropinae is a sister group of the subfamily Oscinellinae.

The species of the genus Rhodesiella Adams, 1905 from Xizang of China are reviewed with the descriptions of the following four new species: R. arcuata sp. n., R. longiseta sp. n., R. perpendicularis sp. n. and R. uncata sp. n. A key to the species of Rhodesiella from Xizang is given. Comments and feature figures of new species are provided for identification. Neorhodesiella Cherian, 2002 is synonymized with Rhodesiella Adams, 1905.