The larva is amphipneustic (has only the anterior and posterior pairs of spiracles) slender tapering at the anterior, and smooth except for ventral creeping welts. The cephalopharyngeal skeleton of the larva consists of two stout untoothed mandibles, a dental sclerite, an elongate hypopharyngeal sclerite, a parastomal bar, and an anvil-shaped tentoropharyngeal sclerite. The anterior spiracles (prothoracic spiracles) each have five to ten papillae which are arranged in a fan shape. The posterior spiracles (on the anal segment) are placed on a raised, sclerotized posterior spiracular tubercle. Each spiracle has three oval, radially arranged slits and four groups of branched spiracular hairs.