ABSTRACT Glena mielkei Vargas, 2010 (Lepidoptera: Geometridae: Ennominae: Boarmiini) is a Neotropical geometrid moth native to the Atacama Desert of northern Chile whose larvae are folivorous on the shrub Trixis cacalioides (Asteraecae). The last instar and pupa are described and illustrated, and DNA barcode sequences are provided for the first time for G. mielkei. Descriptions are made based on larvae collected in the type locality. Comparisons with the available descriptions of congeneric species suggest that the chaetotaxy of the SV group of the abdominal segment and the morphology of the cremaster could be useful tools to species identification based on last instar and pupa, respectively. A search in BOLD (Barcode of Life Data System) showed that the only DNA barcode haplotype found in the two specimens sequenced was closest to Physocleora Warren, 1897 than Glena Hulst, 1896. These results coincide with the morphological peculiarities of the genitalia highlighted in the original description of G. mielkei, suggesting that a definitive assessment of the generic status of this geometrid moth deserves further integrative studies.