The Arthropods of La Selva Project (ALAS) is a quantitative inventory of arthropod biodiversity in a Neotropical rainforest. The project relies on a large team of collaborating taxonomists and an on-site staff of four parataxonomists. The taxonomists provide identification services plus specialized collecting for focal taxa. The parataxonomists carry out structured sampling, specimen processing, and data entry for all survey taxa. From 1992-1999 the project focused on La Selva Biological Station, a 1600ha reserve in the Atlantic lowlands of Costa Rica. Structured sampling included canopy fogging, Malaise traps, Berlese samples, and black-light samples. Focal taxa included Acari (Ceratozetoidea, Ascidae), Araneae (Salticidae), Orthoptera (Tettigoniidae), Coleoptera (hispine Chrysomelidae, conoderine Curculionidae, Buprestidae, Scarabaeinae, Cerambycidae, Cleridae), Lepidoptera (Tortricidae, Gelechioidea, Tineoidea), Diptera (parasitic Phoridae, Asilidae, Stratiomyiidae), and Hymenoptera (rogadine and coenocoeliine Braconidae, banchine, phygadeuontine, and pimpline Ichneumonidae, Formicidae). Current work expands sampling across a 2000m elevational gradient in the adjacent national park.