White-bowed Smoothwing

The White-bowed Smoothwing (Scaeva pyrastri) is a medium-sized, black-and-white, Holarctic flower fly. The oval abdomen has paired white markings that are curved like parentheses and which do not reach the abdomen margin. The coloration of this species sets it apart from nearly all other species in the Syrphinae which have yellow markings. The r4+5 vein is not straight but has a noticeable, upward curve. The larvae are entomophagous, consuming mostly aphids. One study reported a single larva consuming close to 500 aphids.

Flight Dates: June

Flowers: Tends to prefer blue flowers. Has been observed on Blue Flax (Linum lewisii) in Minnesota

Similar species: Scaeva selenitica which has yellowish markings instead of white and Eupeodes volucris , a western, montane species, which differs in having a straighter r4+5 vein.

Field Notes: This species is thought to be a migrant in Europe. Also, rarely, a melanistic form, without the characteristic white spots on the abdomen, has been observed.

Scaeva pyrastri – Marshall County – June 10, 2016