ABSTRACT Insects are fundamental to biodiversity conservation in almost all ecosystems, and their population decline, and extinction directly result from environmental impacts. These facts are aggravated by the lack of knowledge of insect biodiversity, the so-called biodiversity deficits, especially the Linnean and Wallacean shortfalls. In freshwater ecosystems, biodiversity loss is higher among aquatic insects, and caddisflies comprise one of the most vulnerable orders. In this way, research focusing on describing new caddisfly species and understanding their distribution ranges will increase knowledge of caddisfly biodiversity. In the past 14 years, the team from the Laboratório de Entomologia Aquática “Prof. Dr. Claudio Gilberto Froehlich” (LEAq, Universidade Federal da Bahia, Brazil) and collaborators have been addressing these issues, resulting in 55 described species of caddisflies. Taxa in other insect orders have also received attention and an additional 16 species have been described (eight mayflies, four stoneflies, four neuropteran spongillaflies, and antlions). Here, eight caddisfly species are described and illustrated (Atopsyche froehlichi sp. nov., Austrotinodes zeferina sp. nov., Cernotina kariri sp. nov., Neoathripsodes froehlichi sp. nov., Notalina claudiofroehlichi sp. nov., Oecetis marcus sp. nov., Phylloicus froehlichi sp. nov., and Polycentropus claudioi sp. nov.), five of them in honor of LEAq’s patron. In addition, new distributional data are presented for 10 known species. A checklist of the caddisfly fauna of Bahia state is also presented, with 138 species, around 75% and 30% of them recorded and described by the LEAq team, respectively. Currently, for caddisflies, Bahia is the fifth most species-rich state in Brazil, and the first in the Brazilian Northeast region.

Abstract Austrolimnius cleidecostae sp. nov. is one of the smallest species of Elmidae from the Neotropical region. The new species is described and illustrated based on male and female specimens. This species represents the first record in Elmidae of mandibles with an articulated, sclerotized process on inner subapical edge. The specimens were collected from streams in the Atlantic rainforest of São Paulo and Santa Catarina, and habitat notes are given. An updated key for the AustrolimniusCarter & Zeck, 1929 of Brazil is provided. Austrolimnis browniHinton, 1971 and A. musgraveiHinton, 1939 are recorded for the first time from Brazil.

The stonefly (Pleeoptera) nymphs of streams of the Almas River basin, Pirenópolis, Goiás State, Central Brazil, and some abiotie factors that might affect their temporal distribution were studied. Nymphs were sampled monthly (June 1993 to July 1994) in five stations with a Surber sampler, and each sample consisted of 20 units totalling 2 m². In each station, stream velocity, discharge, temperature, electrical conductivity and pH were measured in order to assess their influence on the density of nymphs. Nymphs were identified to genus level. In general, the annual variation in density of nymphs, in four stations, showed that the seasonal variation was not clearly influenced by the annual rain cycle. In the case of the one of the stations, where numbers of stonefly nymphs were low and the anthropic action high, there was a density peak in the rainy season. This peak was probably related to dilution of the organie pollution in the rainy season, improving the environmental conditions for the Pleeoptera.

The Trichoptera fauna in two first-order streams of Serra dos Pireneus. Goiás State, was studied from June/1993 to July/1994. The Trichoptera larvae abundances were lower in the rainy season in the two streams. The temporal distributions of the functional groups (feeding categories) was similar in both streams. The ordination by Detrended Correspondence Analysis (DCA) detected a higher temporal heterogeneity of the Trichoptera community in one of the sampling stations, probably associated with higher discharge variation. There is a large variation of abundance of some genera between the two studied streams.

Relationships among some abiotic factors (temperature, velocity, flow, conductivity, oxy-reduction potential and pH) and the seazonal density of benthic insects (immature forms) of the orders Ephemeroptera, Plecoptera and Trichoptera at the Parque Ecológico de Goiânia, Goiás are studied. An area of 1m² was sampled and abiotic factors were recorded in 4 sites from August/1994 to July/1995. The faunistic composition was 75% Ephemeroptera, 1% Plecoptera and 24% Trichoptera. The data suggest the water velocity and flow as the main factors that determined the aquatic insects abundance.