Abstract: Among Australian caddisflies (Insecta: Trichoptera), the leptocerid genus Oecetis McLachlan is one of the most widespread and diverse genera. This paper brings to 53 the number of described species recorded for Australia, and at least a further 15 to 20 species remain to be described. Here 17 newly described species are assigned with 12 others to an informal laustra-group, defined by having the phallus simple and lacking parameres. Three other newly described species are placed in another informal group, the longiterga-group, based on the broad form of the forewing and strongly pronounced venation. Distributions are plotted for most species, new records extending distributions considerably; of the 29 laustra-group species included here, 15 are known in Australia only from the north of the continent. Keys are provided to the informal species-groups recognised for Australia, and to males of the laustra- and longiterga- groups.
Keywords: Taxonomy, Trichoptera, Leptoceridae, Oecetis, new species, Australia
Citation: Wells, A., 2004. The long-horned caddisfly genus Oecetis (Trichoptera: Leptoceridae) in Australia: two new species groups and 17 new species. Memoirs of Museum Victoria 61: 85-110. http://doi.org/10.24199/j.mmv.2004.61.7