Toxomerus geminatus

Flower Fly
Toxomerus geminatus

Flower Fly Toxomerus geminatus female. May 08, 2009 Wheatley, Ontario.
Flower Fly Toxomerus geminatus female. May 08, 2009 Wheatley, Ontario.

Identification:
Head: Face whitish, projecting on both male and female. Eyes red. On female, white stripe up inner eye margins to top of head, rest dark. On male, eyes touching at top of head, white area below. Hind margin of eyes indented at middle, covered with white hair.
Antenna: Yellow, last segment lighter, almost white.

Flower Fly Toxomerus geminatus male on Goldenrod. Oct 2, 2014, Wheatley, Ontario.
Flower Fly Toxomerus geminatus male on Goldenrod. Oct 2, 2014, Wheatley, Ontario.

 

Thorax: Segment 1 (scutum) bronze-brown with 3 faint longitudinal lines of whitish pile; side edges outlined in yellow. Segment 2 (scutellum or half-moon) bronze-brown, lower margin outlined in yellow.  Thorax sides darker bronze-brown; oval yellow spot near wing base, another whitish spot below it.
Wings: Slightly tinted, veins black except at base, more yellowish. Halteres yellow.

Flower Fly Toxomerus geminatus female. August 6, 2013, Wheatley, Ontario.
Flower Fly Toxomerus geminatus female. August 6, 2013, Wheatley, Ontario.

Legs: Female: Front and mid legs yellow; hind thigh (femur) with brown ring before tip. Shin (tibiae) and foot dark with yellow rings.
Male: Front and mid legs slightly darker yellow than female. Hind legs dark with yellow tips on all segments; thigh slightly swollen.
Abdomen: Black with yellow pattern.
Segment 1: Yellow stripe across base.
Segment 2: Long stripe down middle of segment, wider at base; yellow, lobed stripe on each side, covering base half of segment.

Flower Fly Toxomerus geminatus male. Oct 5, 2011, Wheatley, Ontario.
Flower Fly Toxomerus geminatus male. Oct 5, 2011, Wheatley, Ontario.

Segment 3: Same as two, but lobes a little longer, sometimes separated on male.
Segment 4: Yellow patch at each side edge, with two shorter teeth-like marks each side of center. Male marks much smaller and shorter; sometimes absent.
Tip black, sometimes with reddish-yellow at base. Underside yellow; male has small projection on segment 2 or 3.

Similar Species: Toxomerus marginatus marks on abdomen cover almost entire segment, no lobes.

Size: 5 to 6 mm.

Habitat: Meadows on foliage and flowers.

Food: Adults drink nectar. Larvae feed on aphids.

Flight Time: June to September.

Life Cycle: Chalky white eggs are laid singly on plants, usually near aphids. Larvae feed and when fully grown, pupate in soil cavities.

Comments: Essex County – Point Pelee National Park, Lake Erie Islands, Ojibway Prairies. Kent County – Rondeau Provincial Park. Widespread across Ontario.

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

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