Study of all flies (Diptera) collected for one year from a four-hectare (150 x 266 meter) patch of cloud forest at 1,600 meters above sea level at Zurquí de Moravia, San José Province, Costa Rica (hereafter referred to as Zurquí), revealed an astounding 4,332 species. This amounts to more than half the number of named species of flies for all of Central America. Specimens were collected with two Malaise traps running continuously and with a wide array of supplementary collecting methods for three days of each month. All morphospecies from all 73 families recorded were fully curated by technicians before submission to an international team of 59 taxonomic experts for identification.Overall, a Malaise trap on the forest edge captured 1,988 species or 51% of all collected dipteran taxa (other than of Phoridae, subsampled only from this and one other Malaise trap). A Malaise trap in the forest sampled 906 species. Of other sampling methods, the combination of four other Malaise traps and an intercept trap, aerial/hand collecting, 10 emergence traps, and four CDC light traps added the greatest number of species to our inventory. This complement of sampling methods was an effective combination for retrieving substantial numbers of species of Diptera. Comparison of select sampling methods (considering 3,487 species of non-phorid Diptera) provided further details regarding how many species were sampled by various methods.Comparison of species numbers from each of two permanent Malaise traps from Zurquí with those of single Malaise traps at each of Tapantí and Las Alturas, 40 and 180 km distant from Zurquí respectively, suggested significant species turnover. Comparison of the greater number of species collected in all traps from Zurquí did not markedly change the degree of similarity between the three sites, although the actual number of species shared did increase.Comparisons of the total number of named and unnamed species of Diptera from four hectares at Zurquí is equivalent to 51% of all flies named from Central America, greater than all the named fly fauna of Colombia, equivalent to 14% of named Neotropical species and equal to about 2.7% of all named Diptera worldwide. Clearly the number of species of Diptera in tropical regions has been severely underestimated and the actual number may surpass the number of species of Coleoptera.Various published extrapolations from limited data to estimate total numbers of species of larger taxonomic categories (e.g., Hexapoda, Arthropoda, Eukaryota, etc.) are highly questionable, and certainly will remain uncertain until we have more exhaustive surveys of all and diverse taxa (like Diptera) from multiple tropical sites.Morphological characterization of species in inventories provides identifications placed in the context of taxonomy, phylogeny, form, and ecology. DNA barcoding species is a valuable tool to estimate species numbers but used alone fails to provide a broader context for the species identified.

Estimations of tropical insect diversity generally suffer from lack of known groups or faunas against which extrapolations can be made, and have seriously underestimated the diversity of some taxa. Here we report the intensive inventory of a four-hectare tropical cloud forest in Costa Rica for one year, which yielded 4332 species of Diptera, providing the first verifiable basis for diversity of a major group of insects at a single site in the tropics. In total 73 families were present, all of which were studied to the species level, providing potentially complete coverage of all families of the order likely to be present at the site. Even so, extrapolations based on our data indicate that with further sampling, the actual total for the site could be closer to 8000 species. Efforts to completely sample a site, although resource-intensive and time-consuming, are needed to better ground estimations of world biodiversity based on limited sampling.

The geographic ranges in Brazil of 4 species of Neriidae are widened. New records are recorded of the following species and Brazilian states: Eoneria blanchardi Aczél, 1951 from Pernambuco and Paraíba, Glyphidops carrerai Aczél, 1961 and Glyphidops filosus (Fabricius, 1805) from Bahia and Paraíba, and Nerius pilifer Fabricius, 1805 from Paraíba. A referential map is included to these species.

We present the first listing of odonatan species (Insecta: Odonata) that occur in the state of Paraíba, Brazil. There are 49 species and 29 genera registered, making Paraíba the third in number of species among the Brazilian states of northeastern region. The families with the largest number of species were Libellulidae, with 31 species and 15 genera, followed by Coenagrionidae with 11 species and 7 genera. Interior regions of the state are under-sampled, which should still lead to an underestimated number of species. In addition, we present taxonomic notes of two species collected during our expeditions: males of Progomphus dorsopallidus Byers, 1934 and females of Macrothemis griseofrons Calvert, 1909. Here, we detail important characteristics and present figures to aid their morphological identifications.

Neomuscina Townsend includes 41 species distributed throughout the Nearctic and Neotropical Regions. Although the genus has a large number of species, it has been ignored and its taxonomy is confusing and has many flaws. In this work we analyzed the following species recorded for Brazil: Neomuscina atincta Snyder, N. atincticosta Snyder, N. capalta Snyder, N. currani Snyder, N. douradensis Lopes & Khouri, N. goianensis Lopes & Khouri, N. inflexa (Stein), N. instabilis Snyder, N. mediana Snyder, N. mimosa Lopes & Khouri, N. neosimilis Snyder, N. nigricosta Snyder, N. paramediana Lopes & Khouri, N. pictipennis pictipennis (Bigot), N. ponti Lopes & Khouri, N. sanespra Snyder, N. schadei Snyder, N. similata Snyder, N. stabilis (Stein), N. transporta Snyder, N. vitoriae Lopes & Khouri and N. zosteris (Shannon & Del Ponte). Neomuscina nigricosta and N. transporta are new distribution records for Brazil. Three new species are described: Neomuscina anajeensis sp. nov. from Anagé (Bahia), Neomuscina maculata sp. nov. from Botelhos (Minas Gerais) and Neomuscina snyderi sp. nov. from Mata de São João (Bahia). An identification key based on the morphological characters of both male and female is provided. Species distributions are discussed and updated, and the number of species now recorded for Brazil is 29.