yellow-shouldered drone fly

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Yellow-shouldered drone fly is a common, hairy, medium-sized hoverfly. It occurs throughout the United States and southern Canada but is most common in central and southwest United States. It is common in Minnesota. Adults are found from late May to mid-September. They feed on flower nectar.

Adults are robust, bee-like in appearance, and ⅜″ to ½″ (10 to 13 mm) in length.

The head is hemispherical and slightly broader than the thorax. There are two large compound eyes on the sides of the head and three small simple eyes (ocelli) in a triangle on top of the head. The compound eyes are dark brown and are densely covered with short erect hairs. On the male they meet at the top of the head. On the female they do not. They are not spotted or banded. The face is densely hairy and is not projected forward. The antennae are short and are inserted near the middle of the head. They are dark brown and have just three segments. The first and second segments are short. The third segment is flat and longest on the bottom, shorter and rounded on top. At the base of the third segment there is a long, forward-pointing bristle (arista) on the upper side. The arista is not feather-like (plumose). It often has a tight group of one to six short bristles on the upper side near the base, but is otherwise bare. Sometimes it is completely bare. The protruding mouthpart (proboscis) is short and fleshy.

The thorax is dark blackish-brown, shiny, unmarked, and densely covered with short, erect, buff-colored hairs. It has three segments. Each segment has four principal exoskeletal plates, one above, one below, and one on each side. The upper (dorsal) plates, from front to rear, are the prescutum, scutum, and scutellum. There is a convex swelling, called the posterior callus or postalar callus, on the upper rear corners of the scutum. All of the hair on the posterior callus and the scutellum is yellow. This is the feature that gives the insect its common name. The scutellum is not fringed.

The abdomen is black and is densely covered with short, buff-colored, erect hairs. It has five segments. The first segment is narrow and entirely black. The second segment has a broad yellowish band that is broken in the middle. The second, third, and fourth segments each have an inconspicuous, thin, white band at the front margin and a conspicuous, narrow white band on the rear margin. The third segment is shiny and black with no orange or yellow markings. The fourth segment has long white hairs on the rear third. The fifth segment is small and entirely black.

The wings are clear. There is a spurious vein between the radius (R) and media (M) veins. The R₄₊₅ vein is deeply bent (sinuous), appearing “bumped” downward in the middle. The anal cell is long and is closed near the wing margin. The marginal, R₁, R₅, and M₂ cells are also closed.

The legs are mostly black. The basal half of the fourth segment (tibia) of each leg is white or yellowish. The last part of the leg (tarsus), corresponding to the foot, is black.

Total length: ⅜″ to ½″ (10 to 13 mm)

Late May to mid-September

Small organisms

Flower nectar

Sources

24, 27, 29, 30, 82, 83.

Telford, Horace S.. (1939). The Syrphidae of Minnesota. University of Minnesota. Minnesota Agricultural Experiment Station.

Common in Minnesota

Location: Woodbury, MN