The Valdivian temperate forest of southern Chile comprises both broad leaf and mixed gymnosperm vegetation, and is usually dominated by southern beech, Nothofagus spp. (Nothofagaceae). These forests often have a distinctive biota, quite separate from that found elsewhere in South America (WWF 2007). For example, the fly family Dolichopodidae is composed primarily of the Sympycninae (Sympycnus s.l.), Diaphorinae, and the genus Chrysotimus Loew 1857 (Peloropeodinae), while other subfamilies show greatly reduced diversity or are totally absent (Van Duzee 1930, Parent 1932). Moreover, there is a similar faunal composition in the Nothofagus forests of New Zealand, Tasmania, and southeastern Australia, suggesting a Gondwanan origin for this ecological association. The subfamily Medeterinae is poorly represented or absent in Nothofagus forests, and only known from Thrypticus Gerstacker 1864, a stem mining genus associated with Poaceae and Cyperaceae in adjacent swamps and marshes (e.g., Bickel 1992). Therefore it is unusual to find a distinctive new medeterine genus in Valdivian forests, and with indications of it being associated with Nothofagus tree trunks.