Abstract
The fauna of the family Stigmaeidae Oudemans on grapevines and weed plants associated with vineyard agroecosystem in the state of Rio Grande do Sul (Brazil) was studied. Five recognized species were reported: Agistemus brasiliensis Matioli et al., 2002, Agistemus floridanus Gonzales, 1965, Agistemus mendozensis Simons, 1967, Zetzellia agistzellia Hernandes and Feres, 2005, and Zetzellia malvinae Matioli et al., 2002. Two new species were described: Agistemus riograndensis sp. nov. and Zetzellia ampelae sp. nov. A pictorial key was compiled to aid in the recognition of these stigmaeids.