black-horned smoothtail

(Epistrophe grossulariae)

Conservation Status
IUCN Red List

not listed

NatureServe

NNR - Unranked

Minnesota

not listed

 
black-horned smoothtail
Photo by Luciearl
 
Description

Black-horned smoothtail is a moderately large, late-season, typical hover fly. It occurs in Europe and North America. In the United States, it occurs in the east from Maine to Pennsylvania, west to Minnesota, and south along the Appalachian Mountains to northern Georgia. It also occurs in the Pacific Northwest. It occurs across southern Canada from Nova Scotia to British Columbia, and north along the West Coast to Alaska. It is uncommon in Minnesota.

Adults are active from early May to October in other parts of their range, but in Minnesota, they have been seen only from July 16 to September 30. They are found in forests, meadows, fields, and along streams. They feed on flower nectar and pollen. The larvae prey on aphids.

Adults are 716 to (10.4 to 15.0 mm) in length. The body is robust and black or brownish black (dark) and yellow.

On the male, the head is hemispherical and wider than the thorax. The back of the head is strongly concave and closely appressed to 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 bare, with no hairs, and they meet at the top of the head. The face is pale yellow, and there is an obscure, brownish, longitudinal stripe in the middle on the lower three-fifths. The protruding mouthpart (proboscis) is short and fleshy. The antennae are short, shorter than the head, and they have three segments. They are usually entirely black, but on some specimens the first segment (scape) is yellowish on the underside. On the third segment there is a stiff, forward-pointing bristle (arista). The arista is bare, not feather-like (plumose). The yellow on the face continues above the antennae on each side to the top of the compound eyes, defining a long, black, isosceles triangle in the middle. There is no yellow directly above the antennae bases.

The thorax is large and 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. The scutum is large, rounded, shiny, and entirely yellow. The hairs on its surface are almost all black. On each side of the scutum, in the shoulder (humeral) area just behind the head, there is a small plate (postpronotum). The postpronotum is bare, with no hairs or bristles. Unfortunately, this is not visible without first removing the fly’s head. The scutellum is large, rounded, shiny, and entirely yellow. On each side of the thorax, the lower front plate of the middle segment (katepisternum) has an upper and a lower patch of hairs. The upper and lower patches are narrowly joined at the rear. On the underside of the thorax, on each side, there is a small area (metasternum) in front of the first segment (coxa) of the front legs. The metasternum has many long pale hairs.

The abdomen is broadly oval to narrowly oval, and it is narrowly flattened (margined) on the sides. It has five visible segments (tergites). The first segment (T1) is short and black above. T2 has a pair of large yellow spots that broaden toward the sides and extend over the front half to two-thirds of the margin. T3 and T4 have a broad yellow band at the front margin. The band does not narrow at the lateral margins. T4 also has a broad band on the rear margin.

On the front legs, the first segment (coxa) is yellow to brown. On the middle and hind legs, the coxa is brown to black. On each leg, the third segment (femur) is mostly yellow. On the front and middle legs, the basal fifth or less of the femur is brown to black. On the rear legs, the basal half or less is brown to black.

The wings are clear. The entire wing surface is covered with minute hairs (microtrichose).

On the female, the compound eyes do not meet at the top of the head. The dark stripe on the face may be narrow or broad but it is always distinct. The femur on the hind legs is often entirely yellow.

 

Size

Total length: 716 to (10.4 to 15.0 mm)

 

Similar Species

 
Habitat

Forests, meadows, fields, and along streams

Biology

Season

One generation per year: July through September

 

Behavior

 

 

Life Cycle

Larvae overwinter

 

Larva Food

Aphids

 

Adult Food

Flower nectar and pollen

Distribution

Distribution Map

 

Sources

24, 29, 30, 82, 83.

12/18/2024    
     

Occurrence

Common in the northeast. Uncommon in Minnesota

Taxonomy

Order

Diptera (flies)

Suborder

Brachycera

Infraorder

Cyclorrhapha

Zoosection

Aschiza

Superfamily

Syrphoidea

Family

Syrphidae (hover flies)

Subfamily

Syrphinae (typical hover flies)

Tribe

Syrphini

Genus

Epistrophe

   

Subordinate Taxa

 

   

Synonyms

Epistrophe conjugens

Epistrophe formosa

Musca formosus

Stenosyrphus grossulariae

Syrphus grossulariae

Syrphus lesueurii

Syrphus melanis

   

Common Names

black-horned smoothtail

 

 

 

 

 

 

 

 

Glossary

Arista

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

 

Coxa

The first segment of the leg of an insect, attaching the leg to the body, and connected to the trochanter. Plural: coxae.

 

Femur

On insects and arachnids, the third, largest, most robust segment of the leg, coming immediately before the tibia. On humans, the thigh bone.

 

Ocellus

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

 

Proboscis

The protruding mouthpart(s) of a sucking insect.

 

Scape

In plants: An erect, leafless stalk growing from the rootstock and supporting a flower or a flower cluster. In insects: The basal segment of the antenna.

 

Scutellum

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.

 

Scutum

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

 

Tergite

The upper (dorsal), hardened plate on a segment of the thorax or abdomen of an arthropod or myriapod.

 

 

 

 

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Luciearl

black-horned smoothtail   black-horned smoothtail

Here's another black-horned smoothtail taken a few days after the previous one I sent. 9/7/24. They must like the white snakeroot (it's spreading around the edge of the yard).

 

Bee on white snakeroot.

MinnesotaSeasons.com Photos
 
   

 

   

 

 

Camera

Slideshows

Epistrophe grossulariae
phrus

Epistrophe grossulariae

Epistrophe grossulariae
Lloyd-Davies

Epistrophe grossulariae
About

Epistrophe grossulariae

 

slideshow

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Other Videos

Hoverfly Epistrophe grossulariae
David Element

About

Mar 29, 2013

The handsome social wasp-mimicking Hoverfly Epistrophe grossulariae has two pale thoracic stripes on the bronze-coloured thorax that assist the observer with identification (as there are many similarly marked hoverflies). The feeding behaviour is distinctive as when feeding from thistles Carduus spp. this fly will often continue to hover with its front legs touching a flower rather than alighting.

Epistrophe grossulariae feeding
Paul Rigg

About

Jul 27, 2015

Epistrophe grossulariae hoverfly feeding at Langold Lake Worksop

Black-horned Smoothtail (Epistrophe grossulariae)
Martin Adlam

About

Jun 10, 2024

Black-horned Smoothtail (Epistrophe grossulariae) on Portland

Epistrophe grossulariae - Zwartsprietbandzweefvlieg
Margaux

About

May 3, 2020

Epistrophe grossulariae foraging on Plantago media. Filmed september 2018 at Torgny (Belgium).

 

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Luciearl
9/7/2024

Location: Lake Shore, MN

Here's another black-horned smoothtail taken a few days after the previous one I sent. 9/7/24. They must like the white snakeroot (it's spreading around the edge of the yard).

black-horned smoothtail

Luciearl
9/3/2024

Location: Lake Shore, MN

Bee on white snakeroot.

black-horned smoothtail
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Created: 12/18/2024

Last Updated:

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