Abstract
Nine species of Harpellales (Zygomycota: Trichomycetes) and one species of Amoebidiales are reported from the northwestern provinces of Tucuman, Salta, and Jujuy in Argentina. New species included Smittium urbanum and Stachylina jujuyensis from Chironomidae larvae and Paramoebidium argentinense from Ephemeroptera nymphs. Harpella tica, previously known only from Costa Rica and Puerto Rico, was found in Simuliidae larvae, sometimes in the same streams with H. meridianalis, a fungus common in simuliids in more southern regions of Argentina and Chile. The warmer stream waters in the northwestern provinces had an impoverished insect fauna and we found fewer species than in the colder streams of Patagonia.