Chloromyia formosa
In 3 days ~10% in a week ~30%
Chloromyia formosa is a species of soldier flies belonging to the family Stratiomyidae. Another name for it is Broad centurion. This species is present in most of Europe (Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, Netherlands, Norway, Poland, Russia, Spain, Sweden, Switzerland, United Kingdom), in the Near East, in the Nearctic realm, and in North Africa.
These flies mainly inhabit wooded areas, hedge rows, moist forests, wet meadows, parks and gardens. Chloromyia formosa can reach a length of 7.3–9 millimetres (0.29–0.35 in) and a wing length of 6–7 millimetres (0.24–0.28 in). Their body is elongated, the thorax is metallic green, the head is hemispherical without hair, while the eyes are quite hairy. Antennae are short, the first antennal segment is longer than the second. The legs are black, only the knees are yellow. The abdomen is flattened and broad.
An evident dimorphism exists between the males and the females of this species. In females the abdomen is blue-green with a purple sheen (depending on the light), while in males it shows a copper-green sheen... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Cévennes National Park | 🇫🇷 France | |
| 2 | Fertő-Hanság National Park | 🇭🇺 Hungary | |
| 3 | Pyrénées National Park | 🇫🇷 France | |
| 4 | Sierra de Guadarrama National Park | 🇪🇸 Spain | |
| 5 | Wadden Sea National Park | 🇩🇪 Germany |
With luck
About 10% of wildlife watchers report a Broad Centurion Fly sighting in Sierra de Guadarrama National Park on a given day, based on 14 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 281st most-seen of the 597 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.
May and June
In those months about 10% of wildlife watchers report a Broad Centurion Fly in Sierra de Guadarrama National Park on a given day, against under 5% in July to April, the lowest months.
Between 5 and 8 pm
Across all the parks we cover, that three-hour window holds the most Broad Centurion Fly sightings with a recorded time, and about 7 in 10 of them come between 6 am and 6 pm: it is most active around dawn and dusk.
Among the best
Of the 5 parks where we can rate Broad Centurion Fly sightings, Sierra de Guadarrama National Park ranks 4th at about 10%, level with the leaders once rounded. The best odds are in Cévennes National Park (France, about 10%), Fertő-Hanság National Park (Hungary, about 10%) and Pyrénées National Park (France, about 10%).
Same order: Diptera
The closest relatives of the Broad Centurion Fly that you can see in Sierra de Guadarrama National Park (order Diptera, Flies) are Common Drone Fly (about 10%), Volucella elegans (about 10%) and Tapered Drone Fly (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Broad Centurion Fly is recorded against all the insects logged in Sierra de Guadarrama National Park (14 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.
