Ground-dwelling invertebrate diversity was sampled in four open meadow sites using pitfall traps. Samples were collected twice during one summer season. Organisms were sorted and catalogued to order, in most cases family, and to morphospecies. A total of 9296 individuals representing 370 morphospecies were included in the analysis. Within sites, cumulative invertebrate diversity was strongly correlated with cumulative diversity of beetles and spiders, but only sometimes with ants. The correlation between diversity of a given focal taxon and total invertebrate diversity across sites was strongest for beetles. Results indicate that beetles are the preferred indicator taxon of overall invertebrate diversity when pitfall traps are employed in open meadows.