black-shouldered drone fly

(Eristalis dimidiata)

Conservation Status
black-shouldered drone fly
Photo by Alfredo Colon
  IUCN Red List

not listed


NNR - Unranked


not listed


Black-shouldered drone fly is an early, common, hairy, medium-sized hoverfly. It occurs in the United States east of the Great Plains, and in southern Canada. It is common in Minnesota. It is one of the earliest hoverflies to emerge in the spring. Adults are found from April to late September mostly in forests. They feed on flower nectar. The larvae, known as rat-tailed maggots, are aquatic. They live in polluted water or in wet carcasses. They feed on small organisms.

Adults are robust, slightly bee-like in appearance, and to 916 (10.1 to 14.0 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 and three small simple eyes (ocelli) in a triangle on top of the head. The compound eyes are densely covered with short erect hairs, at least on the upper half. 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 has a tight group of one to six short bristles on the upper side near the base. It is otherwise bare, not feather-like (plumose). The protruding mouthpart (proboscis) is short and fleshy.

The thorax is dark blackish-brown, shiny, unmarked, and densely covered with short, erect, whitish 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. At least some of the hair on the posterior callus and most of the hair on the base of the scutellum is black. This is the feature that gives the insect its common name, but it is difficult to see without a very clear photograph. The scutellum is not fringed.

The abdomen is black and is densely covered with short 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 third segment often has a similar but narrower orangish band. The second, third, and fourth segments each have a narrow white band on the rear margin. The fifth segment is small and entirely black. Some females show no yellow or orange spots on the abdomen.

The wings are mostly clear. Near the wing base there is a short cross-vein, the humeral vein (h), between the costa (C) and subcosta (Sc) veins. From the h to the base the wing is dark brown. Toward the wingtip, the second cell (pterostigma) on the leading edge (costal margin) is dark brown and distinct. 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 and sharply demarcated.




Total Length: to 916 (10.1 to 14.0 mm)


Similar Species






April to late September (CCESR)






Life Cycle


Adults overwinter.


Larva Food


Small organisms


Adult Food


Flower nectar


Distribution Map



24, 27, 29, 30, 82.

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




Common in Minnesota



Diptera (flies)  


Brachycera (circular-seamed flies, muscoid flies, short-horned flies)  


Muscomorpha (=Cyclorrhapha)  
  Zoosection Aschiza  




Syrphidae (hover flies)  


Eristalinae (drone flies and kin)  


Eristalini (rat-tail maggot flies)  
  Subtribe Eristalina  


Eristalis (drone flies)  
  Subgenus Eoseristalis  



Eristalis chalybaeus

Eristalis chalybeus

Eristalis dimidiatus

Eristalis haesitans

Eristalis incisuralis

Eristalis inflexus

Eristalis l'herminierii

Eristalis niger


Common Names


black-shouldered drone fly









A large bristle on the upper side of the third segment of the antenna of a fly.


Costal margin

The leading edge of the forewing of insects



Simple eye; an eye with a single lens. Plural: ocelli.



The tube-like protruding mouthpart(s) of a sucking insect.



The dark, blood-filled second cell at the leading edge of each wing toward the tip on many insects. It is heaver than adjacent, similar sized areas and is thought to dampen wing vibrations and signal mates. (= stigma. More precise than stigma but less often used, even by entomologists.)



The exoskeletal plate covering the rearward (posterior) part of the middle segment of the thorax in some insects. In Coleoptera, Hemiptera, and Homoptera, the dorsal, often triangular plate behind the pronotum and between the bases of the front wings. In Diptera, the exoskeletal plate between the abdomen and the thorax.



The forward (anterior) portion of the middle segment of the thorax (mesonotum) in insects and some arachnids.



The fourth segment of an insect leg, after the femur and before the tarsus (foot). The fifth segment of a spider leg or palp.






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Alfredo Colon

    black-shouldered drone fly   black-shouldered drone fly  
    black-shouldered drone fly      








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Other Videos
  Flower Fly (Syrphidae: Eristalis dimidiata) Bee Mimic
Carl Barrentine

May 16, 2011

Photographed at Grand Forks, North Dakota (16 May 2011). Thank you to Martin Hauser ( for identifying this specimen!

  Bee Mimic Flower Fly (Syrphidae: Eristalis dimidiatus?) Close-up
Carl Barrentine

Apr 24, 2012

Photographed at Grand Forks, North Dakota (24 April 2012).




Visitor Sightings

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  Alfredo Colon

Location: Woodbury, MN

black-shouldered drone fly  
  Alfredo Colon

Location: Woodbury, MN

black-shouldered drone fly  
  Alfredo Colon
Summer 2019

Location: Woodbury, MN

black-shouldered drone fly  






Created: 1/6/2021

Last Updated:

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