Up to 6 mm long, with thoracic segments swollen and fused; brown head capsule nearly parallel-sided, slightly longer than broad, with mentum, mandible and occipital margin darker; antennae arise from pale area. Eye spot single.
Antenna slightly more than 50% of head capsule length; 5-segmented, 1st segment long and narrow, segments 2 and 3 completely annulate, with segments 4 and 5 subequal, short; blade not extending to apex of segment 2, accessory blade absent. Antennal ratio ca. 1.4. Style hyaline, without Lauterborn organs. Ring organ in basal 1/3, strong seta inserted at 2/3.
Frontoclypeal apotome present. SI, SII and SIII elongate and enlarged, sickle-shaped in lateral view, all arising from distinct pedestals; SIVa rod-shaped, arising from pedestal longer than rod, SIVb rod-shaped. One simple chaeta, seta premandibularis and well-developed, slightly curved labral rod. Pecten epipharyngis of three basally-fused long scales. Premandible absent. Epipharynx with 3-4 pectinate, 2 simple elongate chaetulae laterales, and 2 robust, simple chaetulae basales; without basal sclerite.
Mandible with 7-8 teeth; median tooth slightly larger than subequal others. Seta subdentalis apically pointed, arising from anterior surface of mola, seta interna plumose, located very apically on dorsal mandible.
Mentum flat medially with median tooth narrow and when unworn, medially with slight notch; small first laterals and first 2 larger laterals forming level section, flanked by outer 5-6 diminishing in even slope. Ventromental plate not recognisable. Setae submenti simple, displaced to laterad of base of mentum.
Anterior parapods fused basally, with separate crowns of many serrate claws but without interconnecting fine claws. Spiracles absent. Procercus hyaline, almost indistinguishable from anal tubules, perhaps with small pigmented postero-median field, apically with tuft of short but stout setae. Posterior parapods stout, with numerous pale, simple, long claws arranged in a crown.
Brundin (1966) recognised an unusual pupa with a pair of dorsal large conical protuberances on of abdominal segments I-IV as genus 'Chile'. Molecular data and pharate material allow the larva to be recognised as resembling in most features Podonomopsis, to which it is postulated sister taxon. The main difference appears to be in the stronger procercal apical setae, the eight toothed mandible with strongest tooth in the middle, and perhaps in the details of the median mentum. The displaced setae submenti are shared with Podonomopsis.
Brundin's pupa came from a montane stream and a river near Peulla in the Chilean Lake District. Additional pupae and molecularly associated larvae come from similar flowing waters in the area of Puyehue and Villarrica.