Eristalis saxorum
This record describes Eristalis saxorum (species). Recorded family: Syrphidae. Recorded order: Diptera.
Identification and Appearance
Body variably metallic blue. Pterostigma is a diffuse light brown . Williston ( Synopsis of the North American Syrphidae , 1886) notes: Resembles dimidiatum, but is at once distinguishable by the third segment of the abdomen having an entire posterior, velvety cross-band, by the front (= frons?) in the female being narrowed above, and by the presence of a distinct brown spot on the wings. Little-known species . Weideman's original description (German, blackletter, i.e., Gothic script), perhaps contains a key to the meaning of the species name.
Classification
Habitat and Range
Geographic Range
ME-FL to WY-CO
Seasonal Activity
March-October in south, May to August in Northeastern US
Additional species information
Species notes from the sources
Etymology: Latin saxorum means "of the rocks" (genitive plural of saxum --rock, see Wiktionary ). Perhaps a reference to the blue color of the fly, resembling some minerals?
About Flies: the wider group
Order-level background for Diptera, the group containing Eristalis saxorum. 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 Eristalis saxorum (5)
Photo credits: Contributed by v belov; Additional contributions by cotinis
Frequently Asked Questions About Eristalis saxorum
What is Eristalis saxorum?
Eristalis saxorum is a species in the family Syrphidae, within the order Diptera.
How big is Eristalis saxorum?
11-14 mm length
How do you identify Eristalis saxorum?
Body variably metallic blue. Pterostigma is a diffuse light brown . Williston ( Synopsis of the North American Syrphidae , 1886) notes: Resembles dimidiatum, but is at once distinguishable by the third segment of the abdomen having an entire posterior, velvety cross-band, by the front (= frons?) in the female being narrowed above, and by the presence of a distinct brown spot on the wings.
Where is Eristalis saxorum found?
Range: ME-FL to WY-CO
When is Eristalis saxorum active?
Eristalis saxorum: seasonal activity - March-October in south, May to August in Northeastern US.