Two new genera and five new species of spider flies (Diptera: Acroceridae) are described from the Neotropical Region. A new genus of Philopotinae (Neophilopota brevirostris Schlinger gen. et sp. n.) is described from Mexico, while an unusual new species of Sphaerops Philippi, 1865 (Acrocerinae: Sphaerops micella Schlinger sp. n.) is described from Chile. A new Panopinae genus near Lasia Wiedemann, 1824 (Coquena stangei Schlinger gen. et sp. n.), is described from Argentina and two new species of Pialea Erichson, 1840 (Pialea brunea Schlinger sp. n. and Pialea corbiculata Schlinger sp. n.)are described from Venezuela. Each genus is diagnosed and figured, and a key to species provided. The Neotropical fauna presently includes 19 genera, containing approximately 100 species. A key to New World genera is also included.
Keywords: Acrocerinae; Panopinae; Philopotinae; parasitoid; small-headed flies.