In this study, the mitochondrial genomes of 22 species from three subfamilies in the Sphingidae were sequenced, assembled, and annotated. Eight diurnal hawkmoths were included, of which six were newly sequenced (Hemaris radians, Macroglossum bombylans, M. fritzei, M. pyrrhosticta, Neogurelca himachala, and Sataspes xylocoparis) and two were previously published (Cephonodes hylas and Macroglossum stellatarum). The mitochondrial genomes of these eight diurnal hawkmoths were comparatively analyzed in terms of sequence length, nucleotide composition, relative synonymous codon usage, non-synonymous/synonymous substitution ratio, gene spacing, and repeat sequences. The mitogenomes of the eight species, ranging in length from 15,201 to 15,461 bp, encode the complete set of 37 genes usually found in animal mitogenomes. The base composition of the mitochondrial genomes showed A+T bias. The most commonly used codons were UUA (Leu), AUU (Ile), UUU (Phe), AUA (Met), and AAU (Asn), whereas GCG (Ala) and CCG (Pro) were rarely used. A phylogenetic tree of Sphingidae was constructed based on both maximum likelihood and Bayesian methods. We verified the monophyly of the four current subfamilies of Sphingidae, all of which had high support. In addition, we performed divergence time estimation and ancestral character reconstruction analyses. Diurnal behavior in hawkmoths originated 29.19 million years ago (Mya). It may have been influenced by the combination of herbaceous flourishing, which occurred 26–28 Mya, the uplift of the Tibetan Plateau, and the large-scale evolution of bats in the Oligocene to Pre-Miocene. Moreover, diurnalism in hawkmoths had multiple independent origins in Sphingidae.

A new species of the genus Rhodambulyx Mell, 1939, Rhodambulyx xinyuae sp. nov., is described from Simianshan Nature Reserve in Southwest Chongqing, China. This species is similar to R. davidi Mell, 1939 and R. kitchingi Brechlin, 2015 in habitus, but can be distinguished by a different wing pattern, male genitalia structure and DNA barcode sequence. In addition, Rhodambulyx namvui Eitschberger & Nguyen, 2017 is removed from synonymy with R. kitchingi and synonymized instead with R. davidi, although whether it would be better treated as a subspecies of R. davidi requires further investigation.

Neogurelca montana (Rothschild & Jordan, 1915) is a species of the genus Neogurelca Hogenes & Treadaway, 1993, that was previously known from Sichuan, Yunnan, and Tibet, China. Recently, however, this species was also found in Beijing and Hebei. These populations differ from those in southwest China in body colour and the shape of the yellow patches of the hindwing—a paler body colour and triangular patches in the former and darker body colour and fan-like patches in the latter. Wing morphology, male and female genitalia, and molecular evidence (DNA barcodes) were analysed for the different localities of this species and three other Neogurelca species—N. hyas, N. himachala, and N. masuriensis. Our molecular data support the Beijing population of montana as a valid subspecies, which we describe as N. montana taihangensis ssp. nov. Wing and genital morphology confirm the molecular conclusions. We also collected larvae of the new subspecies in the Beijing suburbs and describe its life history and larval hosts and compare them with those of N. himachala.

Here, the taxonomy of the genus Rhagastis Rothschild & Jordan, 1903 (Lepidoptera, Sphingidae, Macroglossinae, Macroglossini) from China is revised based on differences in wing morphology, male and female genitalia, and the phylogenetic relationship of the DNA barcodes. Subspecies of Rhagastis albomarginatus (Rothschild, 1894) and R. castor (Walker, 1856) are treated as “good” species, namely Rhagastis dichroae Mell, 1922 stat. nov.; R. everetti Rothschild & Jordan, 1903 stat. nov.; R. aurifera (Butler, 1875) stat. rev.; R. chinensis Mell, 1922 stat. nov.; R. formosana Clark, 1925 stat. nov.; and R. jordani Oberthür, 1904 stat. rev. The distribution maps, biological notes, and ecological records of the genus Rhagastis Rothschild & Jordan, 1903 from China are given, and a species inventory of genus Rhagastis in the world is also included.

The taxonomy of genus Ambulyx Westwood, 1847 from China is reviewed based on analysis of wing morphology, male and female genitalia and phylogenetic relationships derived from DNA barcodes. A new species, Ambulyx wukong sp. nov. is described from NW Yunnan, China. A male of the rare species, A. zhejiangensis from Yintiaoling Nature Reserve, Chongqing, China is examined and its male genitalia illustrated for the first time. Two taxa are newly recorded from China, A. tattina tattina from Xishuangbanna, Yunnan, and A. semiplacida montana from Pingbian, Yunnan. Distribution maps, biological notes, and ecological records are also given.

Two new species of the genus Palpifer Hampson, 1893 are described. The first species, named P. qinglai sp. nov. from Yunnan University in Kunming, Yunnan, China, is similar to P. sexnotatus (Moore, 1879) but distinguished by differences in forewing pattern, male genitalia structure and DNA barcode sequence. The second species, named P. bazi sp. nov. from Mengzi, Honghe, Yunnan, China, resembles P. boonei Grehan & Mielke, 2019 but also differs in the same characteristics.