Eristalinus aeneus

Flower Fly
Eristalinus aeneus

Flower Fly Eristalinus aeneus female on Cup Plant. Aug 03, 2010, Wheatley, Ontario.
Flower Fly Eristalinus aeneus female on Cup Plant. Aug 03, 2010, Wheatley, Ontario.

Identification: Introduced from Europe.
Head: Face brownish-white with pale yellowish to white pile. Eyes large, yellowish-brown with pin-hole sized brown dots blending until eyes become brown at top. Male eyes touching just above antenna base. Female eyes not touching, dark brown between eyes above antenna.

Flower Fly Eristalinus aeneus male on Viburnum (Arrowwood), June 11, 2008, Wheatley, Ontario.
Flower Fly Eristalinus aeneus male on Viburnum (Arrowwood), June 11, 2008, Wheatley, Ontario.

 

Antenna: Light brown, sometimes more reddish. Bristle (arista) long.
Thorax: Metallic dark green to brassy. 5 long, whitish pile stripes start at base and continue to mid thorax; obvious on female, faint to absent on male. Thorax sides with some yellowish hair.
Wings: Clear, veins yellowish brown at base, becoming black nearer tips. Halteres brownish-yellow.
Legs: Thighs (femora) brown, tips yellow. Front and middle shin yellow, with yellowish hair, hind shin more brownish. Feet dark, toes yellow.

Flower Fly Eristalinus aeneus female on Ox-eye Daisy, June 01, 2008, Wheatley, Ontario.
Flower Fly Eristalinus aeneus female on Ox-eye Daisy, June 01, 2008, Wheatley, Ontario.

Abdomen: Abdomen shiny, brassy with short yellowish-white hair. Segments may have obscure white pile (visible in certain lights) at base of segments 3 and 4.

Size: 8 to 10 mm.

Habitat: Forests with vernal pools, wet meadows, lake and river shores.

Food: Adults feed on flower nectar.

Flower Fly Eristalinus aeneus male on Aster, Sept 27, 2007, Wheatley, Ontario.
Flower Fly Eristalinus aeneus male on Aster, Sept 27, 2007, Wheatley, Ontario.

Flight Time: April to October.

Life Cycle: Larvae, called rat-tailed, live in vernal pools, fetid water, fresh water and rock pools filled with seaweed. Pupate at bottom of pool in sand in late summer. New adults then hibernate for winter, some apparently using old mud dauber wasps nests, or tunnels of ground nesting bees in protected locations (i.e. under bridges). Reported 6 to 8 in one mud dauber cell (both male and female). One generation per year.

Comments: Essex County – photos. Map by Skevington shows locations along the Great Lakes.

For information on synonyms, references and type specimens see next page

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