Rhadiurgus variabilis (Zetterstedt)

Lavigne, Robert J. & Dennis, Steve, 2019, Robber flies (Insecta: Diptera: Asilidae) of Wyoming, USA with keys to genera and species, Zootaxa 4662 (1), pp. 1-126 : 60-61

Rhadiurgus variabilis (Zetterstedt)

Asilus variabilis Zetterstedt, 1838: 506 .

Recognition Characters: Dark grayish species; length 11–15 mm; mystax with black bristles above and white below; scutellar bristles 4–6 black on margin that curve up; wings slightly fumose to grayish fumose, almost hyaline basally, veins blackish brown; abdomen black above, with gray lateral margins on segments, without strong bristles, few short setae; legs, femora black with fine white setae and black bristles, tibiae and tarsi dark red to almost black; female with conical ovipositor.

Distribution: YELLOWSTONE NATIONAL PARK: 13 km SE of Old Faithful area, 4 Aug. 1964 ( BDN) (specimen in CAS).

Habitat: Douglas fir forest (clearings within the forest where shrubs and grasses are dominant) vegetation type. Cannings (1993) indicates that, “ In North America the species inhabit the Boreal Forest ” and “ the structure of the habitat may vary considerably, but can generally be described as the edges of, or sunny clearings, in dry coniferous woods in northern subalpine regions.”

Ethology: Cannings (1993) states that, “ Rhadiurgus variabilis usually hunts from the ground or rocks, but also perches on logs and low herbage.”

Prey: None known.