Dendrotelme
Guides
Systenus
Systenus is a genus of long-legged flies (Dolichopodidae: Medeterinae) characterized by larvae that develop in dendrotelme habitats—water-filled hollow tree cavities lined with organic soil. The genus is globally uncommon in collections, likely due to its arboreal adult associations and specialized larval habitat requirements. Despite this rarity, some localities show remarkable species richness; for example, eight species were collected from a single site in Costa Rica. The genus occurs in both tropical and temperate regions, with records from Central America, South America, Europe, and North America.