Thio paper contains descriptions of two new species, Leptogastrothrips hoodi and L. pampicola, together with notes on L. gramins (Hood, 1936) which is noticed as new for this country, and L. wulteri (Watson, 1933).
A key for the separation of the species is given.
Types of the new species and all the documentary specimens treated are deposited in the collections of the Museum at La Plata.