A new species of Oecetis McLachlan, 1877 (Trichoptera: Leptoceridae) from Southeast Brazil: Validation of an unpublished species

Oecetis McLachlan is the most speciose genus within the Leptoceridae Leach, 1815. It contains more than 400 species distributed all over the world except Antarctica. The genus is easily recognized by its apparently unbranched M vein in the forewings, a character that McLachlan used to differentiate this genus from Setodes. Milne divided the genus into four subgenera, Quaria being one of them. The males of this subgenus are recognized by their prominent dorsolateral processes from abdominal segment IX in lateral view. Chen, in his unpublished PhD thesis, recovered this subgenus and erected three others based on a phylogenetic analysis. Herein we describe a new species collected in Southeast Brazil based on male specimens. This species was described by Chen but not published. The new species is recognized by its dorsolateral process on segment IX being slender, curved ventrad, and with the same length as the phallic apparatus, and by its inferior appendages each with its distal lobe cylindrical.