The development of the pupal dorsal apotome was examined and compared in representatives of the families Culicidae, Chaoboridae, Corethrellidae, and Dixidae. Illustrations of the pupal dorsal apotome for 73 species, in 25 genera, are provided to show the differences and similarities between taxa. The 4th-instar larval dorsal apotome is compared and illustrated for the 3 subfamilies of Culicidae. The phylogenetic significance of the dorsal apotome of the pupae and 4th-instar larvae is discussed.