The Bat-Winged Fly is found in the Paparoa Range south of Fiordland. Like other alpine insects (butterflies, cicadas) it basks in the sun on stones and rocks; presumably absorbing heat/energy from the sun and this is amplified for the male by his large, dark, pantaloon wings.
DoC's Threatened Species Ambassador, Nicola Toki tells us all about this large winged critter.