Ovaustra aurantia Tetley, Glatz & Fagan‐Jeffries, gen. et sp. nov. (Mesostoinae) is described from Kangaroo Island. South Australia, Australia, and is a solitary, koinobiont, egg‐larval parasitoid of the enigma moth, Aenigmatinea glatzella Kristensen & Edwards, 2015, in the monotypic family Aenigmatineidae Kristensen & Edwards, 2015 (Lepidoptera). Female parasitoids oviposit into the eggs of A. glatzella soon after female moths place them beneath minute adpressed leaves at the growing foliar tips of the larval host plant Callitris gracilis R.T. Baker (Cupressaceae). Adult parasitoids emerge from A. glatzella larval chambers located directly beneath the bark of small branches, some way from the growing tip. Adults can be seen on or near foliage of C. gracillis primarily during October and coinciding with the presence of adult host moths. Morphological and preliminary molecular evidence place Ovaustra Glatz, Fagan‐Jeffries & Tetley, gen. nov. within Mesostoinae s.l. and indicate that its closest relatives are likely to reside within a group of genera from Australia and New Zealand whose hosts and biology are not well defined but are apparently quite broad, including lepidopteran, coleopteran and dipteran larvae, as well as primary plant gall induction.