Four-lined Hornet Fly
Spilomyia sayi
This record describes Spilomyia sayi (species). Recorded family: Syrphidae. Recorded order: Diptera.
Identification and Appearance
Four-lined Hornet Fly (Spilomyia sayi) is a species in the family Syrphidae, commonly known as hover flies, belonging to the order Diptera (Flies). It is classified within the subfamily Eristalinae, tribe Milesiini, superfamily Platypezoidea. This species belongs to the genus Spilomyia. As a member of class Insecta, phylum Arthropoda, it is part of the kingdom Animalia. Size: 12-16 mm. It is found in Larvae found in the decaying heartwood of deciduous trees. Adults most commonly found around wetlands and sometimes encountered hilltopping. Active during Jul-Oct in ON.
Classification
Habitat and Range
Habitat
Larvae found in the decaying heartwood of deciduous trees. Adults most commonly found around wetlands and sometimes encountered hilltopping
Geographic Range
NB-AB south to NJ-KS
Seasonal Activity
Jul-Oct in ON ( 3 )
Additional species information
Species notes from the sources
Etymology: Spilomyia sayi (Goot, 1964)
About Flies: the wider group
Order-level background for Diptera, the group containing Spilomyia sayi. Species-specific details appear above.
Group overview
Diptera includes over 150,000 described species of flies, mosquitoes, and midges. Mosquitoes are the deadliest animal on Earth (CDC). Malaria alone causes ~249 million cases and over 608,000 deaths annually, mostly children under 5 (WHO). Vector-borne diseases account for over 17% of all infectious diseases, causing 700,000+ deaths per year.
Ecological role of the group
Despite their disease impact, flies are critical decomposers and pollinators. Hoverflies alone pollinate hundreds of crop and wildflower species. Flies are also the primary food source for many birds, bats, and fish. Forensic entomology relies heavily on fly species for crime scene analysis.
Economic and practical significance of the group
In the U.S., vector-borne disease cases tripled between 2004-2016, with over 640,000 cases reported in that period (CDC). Tickborne diseases doubled from 22,000 to 48,000 annual reports. Globally, mosquito-borne diseases cost billions in healthcare and lost productivity.
Recorded sources for this group: WHO, CDC, PNAS. Imported estimates may describe particular regions or reporting periods.
Photos of Four-lined Hornet Fly (5)
Photo credits: Contributed by Cotinis; Additional contributions by Tom Bentley , Beatriz Moisset , Robin McLeod , v belov , Marci Hess , PaleoJon
Frequently Asked Questions About Four-lined Hornet Fly
What is Four-lined Hornet Fly?
Four-lined Hornet Fly (Spilomyia sayi) is a species in the family Syrphidae, within the order Diptera.
How big is Four-lined Hornet Fly?
12-16 mm
Where is Four-lined Hornet Fly found?
| Feature | Details |
|---|---|
| Habitat | Larvae found in the decaying heartwood of deciduous trees. Adults most commonly found around wetlands and sometimes encountered hilltopping |
| Range | NB-AB south to NJ-KS |
When is Four-lined Hornet Fly active?
Four-lined Hornet Fly: seasonal activity - Jul-Oct in ON ( 3 ).