AbstractVermileonidae (wormlions) comprises 61 described species in 12 genera and is one of the oddest and most rarely collected dipteran families. Larvae of Vermileonidae are famous for their pitfall prey behaviour, whereas the adults are rarely seen. Here we report, for the first time, the complete mitochondrial genome from members of Vermileonidae. Phylogenetic reconstruction based on a representative sampling of the order reveals new insights into relationships between the Vermileonidae and other members of lower brachyceran flies. A sister-group relationship between Vermileonidae and Xylophagidae is supported, and the higher-level clade relationships are Tabanomorpha + (Muscomorpha + (Xylophagomorpha + Stratiomyomorpha)). Combining mitochondrial genome data with a morphological phylogeny, geographical distribution and geological history, we propose that the Vermileonidae originated in India during the Middle Jurassic, spreading to Africa via land bridges during the Late Jurassic, to the Palaearctic after the collision of India with Laurasia in the Late Oligocene, and to the Nearctic in the Early Miocene, via either North Atlantic or Beringian land bridges. Wet forested regions have proved to be barriers to their dispersal, explaining their absence from Central Africa, South America and eastern North America.