Thereva Latreille

Thereva Latreille Thereva is widely Holarctic but also lives in parts of the Afrotropical Region (Irwin & Lyneborg 1980, Holston et al. 2007). In the Nearctic it is mostly found in boreal and mountainous habitats. It is by far the most diverse genus in the region under investigation, with 19 species recorded. Thereva species are often collected in woodland; the adults often perch on vegetation and, compared to those of other genera, can be sluggish fliers (Marshall 2012). Holston & Irwin (2005) key the North American species.