Epistrophe grossulariae
In 3 days ~10% in a week ~30%
Epistrophe grossulariae is a Holarctic species of hoverfly. External images For terms see Morphology of Diptera Wing length 9-12·25 mm. Thorax dull greenish. Tergite 4 with entire yellow band. At least anterior femora dark at base, sometimes hind also. Frons black above lunule and at least half black-haired. Female has a bronzy-green area on upper part of frons. Yellow bands on tergites 3 and 4 straight. Tergite 5 with black band.
Male genitalia are figured by Hippa (1968). The larva is illustrated by Rotheray (1993) Palaearctic and Nearctic Fennoscandia South to Spain, Italy and Yugoslavia. Ireland eastwards through Turkey Russia to Kamchatka. In North America from Alaska to Quebec and South to California.
Habitat is deciduous woodland, particularly along rivers and streams, Salix swamp woodland, alpine grassland. Found in clearings, tracksides and beside streams. Flowers visited include white umbellifers, Centaurea, Cirsium, Filipendula, Geranium, Knautia, Rhododendron, Rubus, Sambucus nigra, Succisa,
Valeriana. The flight period is end June to September. The larva feeds on aphids. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Shenandoah National Park | 🇺🇸 United States | |
| 2 | Great Smoky Mountains National Park | 🇺🇸 United States | |
| 3 | Cairngorms National Park | 🇬🇧 United Kingdom | |
| 4 | Acadia National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Manchester | 🇬🇧 United Kingdom | |
| 2 | Birmingham | 🇬🇧 United Kingdom | |
| 3 | Leeds | 🇬🇧 United Kingdom | |
| 4 | Liverpool | 🇬🇧 United Kingdom | |
| 5 | Edmonton | 🇨🇦 Canada | |
| 6 | London | 🇬🇧 United Kingdom | |
| 7 | Boston | 🇺🇸 United States | |
| 8 | Moscow | 🇷🇺 Russia | |
| 9 | Montreal | 🇨🇦 Canada | |
| 10 | Vancouver | 🇨🇦 Canada |
Rare
Under 5% of wildlife watchers report a Black-Horned Smoothtail sighting in Acadia National Park on a given day, based on 7 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 304th most-seen of the 405 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
August and October
In those months about 10% of wildlife watchers report a Black-Horned Smoothtail in Acadia National Park on a given day, against under 5% in September and November–July, the lowest months.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Black-Horned Smoothtail sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
4th of 4
Of the 4 parks where we can rate Black-Horned Smoothtail sightings, Acadia National Park ranks 4th at under 5%. The best odds are in Shenandoah National Park (United States, about 10%), Great Smoky Mountains National Park (United States, about 10%) and Cairngorms National Park (United Kingdom, about 10%).
Same family: Syrphidae
The closest relatives of the Black-Horned Smoothtail that you can see in Acadia National Park (family Syrphidae, Hover Flies) are Margined Calligrapher (about 20%), Eastern Calligrapher (about 20%) and Common Drone Fly (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Black-Horned Smoothtail is recorded against all the insects logged in Acadia National Park (7 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
