Family common name: common sawflies
Genus: Rhogogaster Konow, 1884
Subgenera: Rhogogaster, Cytisogaster
The Tenthredinidae are the most species-rich family and are found throughout the world, in all continents but Antarctica. They are known as the “common sawflies.” They can generally be recognized by a cylindrical body and long, segmented antennae. Otherwise, they come in a variety of colors, sizes, and forms (Goulet 1992).
Sawflies in the Tenthredininae subfamily are relatively large compared to others in the family, often with distinct colorful markings. Some are wasp-like with black and yellow stripes (Goulet 1992). Many species’ life histories are not known. Some Tenthredininae species feed uniquely, as adults, on flower pollen and other insects (Smith 1993). They can be distinguished from other subfamilies by wing venation (Goulet 1992).
Rhogogaster is a unique sawfly often recognized by large size, angular facial features, and bright green coloring that often fades to light yellow in dead specimens (Benson 1965b, Taeger and Vitsaari 2015).
Rhogogaster can be confused with similar species in the subfamily Tenthredininae. It can be distinguished from most other genera by the obtuse angle on the posteroventral area of metepimeron, the ocellar ridge, and the ventral angle of the compound eye. Rhogogaster can be distinguished from closely related Tenthredo by the size of the eye, the apical margin of the labrum, and a lack of furrow on the pronotum (Goulet 1992).
Rhogogaster in North America feed on Filipendula, Stellaria (chickweed), Circaea (enchanter’s nightshade), Populus (poplar), Alnus (alder) and Ranunculus (buttercup) (Goulet 1992).
There exist a few records of Rhogogaster adults predating on other insects, including flies and, in one case, Nematinae sawflies (Taeger and Vitsaari 2015).
North America: Rhogogaster occurs in western North America from Alaska and British Columbia south to California, east to the Rocky Mountains, the Great Lakes region, and New York (Ross 1943b).
Map data from: GBIF.org (29 October 2019) GBIF Occurrence Download Rhogogaster
Details about data used for maps can be found here.