Some regions, such as the Northeast Region of Brazil, are still severely understudied and the trichopteran fauna of this region is not entirely known, mainly in areas from Cerrado and Caatinga biomes. Currently, 25 species have been reported from Piauí State, but most of these records are concentrated from one locality. This study aimed to update the knowledge of Trichoptera diversity in this state, including the description of a new species and new geographic records for the Northeast region and Brazil. The samples were collected in seven municipalities, using various traps. Specimens were also received from the municipality of Bom Jesus. Thirty-two species were added for Trichoptera fauna of Piauí, 14 of these represent new records for Northeast Brazil; furthermore, Neotrichia palma Flint 1982 is a new record for Brazil. Additionally, a new species, Cernotina longa sp. nov., is describe and illustrate, being the third nominal record of the genus for the Caatinga biome. Thus, with the contribution of this study, 57 species, 20 genera and seven families of caddisflies are known for Piauí State.

Helicopsyche von Siebold, 1856 is divided into six subgenera, of which two occur in Brazil: H. (Cochliopsyche) with nine spp. and H. (Feropsyche) with 25 spp. Although the latter subgenus is the most species-rich in the country, only three species are known from the Brazilian Amazon. In this study, we describe and illustrate two new species for Central Amazonia, Brazil: Helicopsyche johansoni sp. nov. and Helicopsyche manaos sp. nov. based on the morphology of adult males. In addition, a map with the distribution of the species of this subgenus for the Brazilian Amazon is provided.

Sixteen species of the microcaddisfly Ochrotrichia Mosely, 1934 (Hydroptilidae) have been recorded so far in Brazil, mainly distributed in the Atlantic Forest of southeastern Brazil. In order to reduce the Linnean and Wallacean shortfalls for the Ochrotrichia Brazilian fauna, we diagnose, describe, and illustrate three new species based on adult males from three protected and preserved areas of the Cerrado biome of Federal District (Central-West region), Minas Gerais (Southeast region) and Tocantins (North region) states; all of them named in honor of three great Brazilian entomologists viz., Ochrotrichia froehlichi sp. nov., Ochrotrichia machadoi sp. nov. and Ochrotrichia nessimiani sp. nov. They can be recognized mainly by the morphology of the tergum X, number, and position of the spine-like setae of the inferior appendages. This contribution represents the first record of Ochrotrichia for the Central-West region, increasing the number of species of this genus in Cerrado biome from one to four, and is the first report of a microcaddisfly for the Federal District. In addition, the genus is reported for the first time from Paraná, São Francisco, and Tocantins hydrographic basins. Finally, we provide a checklist of the Ochrotrichia species from Brazil.

Ochrotrichia Mosely is the most species-rich group of microcaddisflies in the Neotropical Region. However, knowledge about this genus in Brazil is still limited; only 11 species are known, distributed in the Atlantic Forest (9), Caatinga (3), and Amazon (1) biomes. In this paper, three new species of Ochrotrichia are described and illustrated based on adult males collected in the Ducke Forest Reserve, a protected area administered by the Instituto Nacional de Pesquisas da Amazonia (INPA), located in central Amazonia, Brazil. Ochrotrichia belodes sp. nov., O. buenosoria sp. nov. and O. ducke sp. nov. can be recognized mainly by the morphology of tergum X and the inferior appendages. Based on their simple, elongate tergum X, all new species are assigned to the Ochrotrichia xena Group.

The microcaddisfly Neotropical genus Metrichia Ross, is recorded for the first time from the state of Tocantins, northern Brazil, through the discovery of two species: Metrichia elongata sp. nov. and Metrichia vulgaris Santos, Takiya & Nessimian 2016. Herein, the new species is described and illustrated based on males collected in a protected and preserved area in Cerrado biome of Tocantins. Metrichia elongata sp. nov. can be recognized mainly by the type and position of setae on the inferior appendages and morphology of the dorsolateral hook. The discovery of these species increases the number of Metrichia species in the Brazilian Cerrado from seven to eight and are only the eleventh and twelfth caddisfly species reported for Tocantins State.

Despite being the subgenus with the highest number of species within Chimarra Stephens, 1829 in Brazil, information about Chimarra (Curgia) Walker, 1980 is scarce in the Brazilian semi-arid region. Beyond the discussion about the quantity of species reported for this region, there is also a temporal gap concerning original descriptions of this subgenus in Brazil. Thus, 15 years after the last description of C. (Curgia) in Brazil, we diagnosed, described, and illustrated two new species based on adult males collected in the Caatinga and Cerrado biomes in the state of Piauí, viz., Chimarra (Curgia) opala sp. nov. and Chimarra (Curgia) prata sp. nov. They can be recognized mainly by the morphology of tergum X, preanal appendage, and phallotheca spines. Moreover, they do not conform to the characteristics of any species group traditionally known in the genus. While sharing similarities with the species compared in this study, these comparisons are limited to isolated characters and do not encompass all the features representing the groups of their respective species.