The eggs and all four larval instars of Austroconops mcmillani Wirth and Lee and A. annettae Borkent, new species, are described. The pupa of A. mcmillani is also described. Life cycles and details of behavior of each life stage are reported, including feeding by the aquatic larvae on microscopic organisms in very wet soil/detritus, larval locomotion, female adult biting habits on humans and kangaroos, and male adult swarming. Austroconops annettae Borkent, new species, is attributed to the first author. Cladistic analysis shows that the two extant Austroconops Wirth and Lee species are sister species. Increasingly older fossil species of Austroconops represent increasingly earlier lineages. Among extant lineages, Austroconops is the sister group of Leptoconops Skuse, and together they form the sister group of all other Ceratopogonidae. Dasyhelea Kieffer is the sister group of Forcipomyia Meigen 1 Atrichopogon Kieffer, and together they form the sister group of the Ceratopogoninae. Forcipomyia has no synapomorphies and may be paraphyletic in relation to Atrichopogon. Austroconops is morphologically conservative (possesses many plesiomorphic features) in each life stage and this allows for interpretation of a number of features within Ceratopogonidae and other Culicomorpha. A new interpretation of Cretaceous fossil lineages shows that Austroconops, Leptoconops, Minyohelea Borkent, Jordanoconops