This study presents the first morphological description and illustration of the late instar larva of Limnephilus atlanticus Nybom 1948, an endemic caddisfly from the Azores. Taxonomic comparisons with a recently recorded limnephilid species, Limnephilus affinis (Limnephilidae), and notes of their ecology and distribution in the Azores are also provided.
Keywords: Trichoptera, caddisflies, taxonomy, larval stage, morphology, ecology, distribution.