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Family Syrphidae - Hover Flies

Eristalis transversa? - Eristalis transversa unknown fly - Dioprosopa clavata Syrphid Fly (Chrysotoxum)? - Chrysotoxum  Myolepta strigilata? - Myolepta strigilata Somula decora Syrphid Fly - Toxomerus marginatus - female Eristalis  - Eristalis stipator - female Eristalis dimidiata? - Eristalis hirta
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Diptera (Flies)
No Taxon ("Aschiza")
Family Syrphidae (Hover Flies)
Other Common Names
Flower Flies, Syrphid Flies
Explanation of Names
Syrphidae Latreille 1802
813 spp. in ~100 genera in our area(1)(2), >6,000 spp. in ~210 genera worldwide(3)(4)
Overview of our fauna* –taxa not yet in the guide¹; classification follows(1)(5); for genera represented in our area by a single subgenus, subgenera not indicated.
Family Syrphidae
Tribe Eristalini
Tribe Milesiini
Tribe Rhingiini
Subtribe Rhingiina Rhingia
1-35 mm, typically 10-20 mm
Guides to common species and keys for all Eristalini at (6)

Can be recognized by the spurious wing vein(7):

Many mimic wasps/bees and may even buzz like bees, but do not bite or sting.
Key to nearctic genera in(1) (Note: per Bill Dean, Figure 3 on this page, which purports to depict Lapposyrphus aberrantis, actually depicts Syrphus opinator)
Guide to the northeastern fauna in(8)
Key to Canadian Syrphinae in(9)
Larvae: see(10) and the invitation to submit voucher specimens; larvae of many holarctic genera shown & keyed in(11)
Many adults frequent flowers; some larvae live in ant nests, and a few are associated with wasps.
Larvae may feed on decaying vegetation, aquatic detritus, wet wood, bulbs of forbs of living plants, but most are predators; Many species of Allograpta, Baccha, Mesograpta, Melanostoma, Paragus, Pipiza, Scaeva, Syrphus, Metasyrphus, and Sphaerophoria are important aphid predators; larvae of Baccha, Pipiza, Scaeva, Syrphus, and Metasyrphus feed on coccids. (Weems 1954). Adults often feed on nectar and/or pollen
Life Cycle
Males search for rain-filled tree holes and guard them diligently until a female joins him and lays eggs. When the eggs hatch, they inherit the tree hole.(12)
Larvae (aka rat-tailed maggots) survive in this water with an air tube that acts like a telescoping snorkel; it can stretch several inches or shrink to less than an inch.(12)
Role as aphid biocontrol agents, with many examples & good photos, described in(13)
Larvae that live in water with much decaying organic matter have a long anal breathing tube, and are called "rat-tailed maggots".
See Also
Oestridae, Tachnidae, & some other families also include lookalikes
Print References
Heiss E.M. (1938) A classification of the larvae and puparia of the Syrphidae of Illinois exclusive of aquatic forms. Univ. Ill. Bull. 36: 1-142. (Full text)
Internet References
Works Cited
1.Key to the genera of nearctic Syrphidae
Miranda G.F.G, Young A.D., Locke M.M., Marshall S.A., Skevington J.H., Thompson F.C. 2013. Can. J. Arthropod Identification 23: 1-351.
2.Skevington J.H. (2014) Nearctic Syrphidae checklist
3.Flower Flies (Syrphidae) -
4.Order Diptera Linnaeus, 1758. In: Zhang Z.-Q. (ed.) Animal biodiversity: An outline of higher-level classification...
Pape T., Blagoderov V., Mostovski M.B. 2011. Zootaxa 3148: 222–229.
5.Generic revision and species classification of the Microdontinae (Diptera, Syrphidae)
Reemer M., Ståhls G. 2013. ZooKeys 288: 1–213.
6.Field/Photo ID for Flies: Fly Guide
7.American Insects: A Handbook of the Insects of America North of Mexico
Ross H. Arnett. 2000. CRC Press.
8.Syrphidae of Ontario
9.The flower flies of the subfamily Syrphinae of Canada, Alaska, and Greenland, Diptera: Syrphidae
Vockeroth J.R. 1992. The insects and arachnids of Canada, Pt. 18. Ottawa: Agriculture Canada. 456 pp.
10.Unidentified immature stages
11.Colour guide to hoverfly larvae (Diptera, Syrphidae) in Britain and Europe
Rotheray G.E. 1993. Dipterists Digest No. 9. 155 pp.
12.Hidden Company that Trees Keep: Life from Treetops to Root Tips
James B. Nardi. 2023. Princeton University Press.
13.Flower Flies (Syrphidae) and other biological control agents for aphids in vegetable crops
R. Bugg et al. 2008. UC ANR Publication 8285.
14.Phylogeny of the Syrphoidea (Diptera) inferred from mtDNA sequences and morphology...
Skevington J.H., Yeates D.K. 2000. Molecular Phylogenetics and Evolution 16: 212–224.
15.Phylogeny of Syrphidae (Diptera) inferred from combined analysis of molecular and morphological characters
Ståhls G., Hippa H., Rotheray G., Muona J., Gilbert F. 2003. Systematic Entomology 28: 433–450.
16.A comparative analysis of the evolution of imperfect mimicry
Penney H.D., Hassall C., Skevington J.H., Abbott K.R., Sherratt T.N. 2012. Nature 483: 461–464.
17.The evolution of imperfect mimicry in hoverflies
Gilbert F. 2005. Insect Evolutionary Ecology: Proc. Royal Ent. Society's 22nd Symposium: 231–288.
18.Syrphidae of Oklahoma (Diptera)
Shorter D.A., Drew W.A. 1976. Proc. Okla. Acad. Sci. 56: 75-94.
19.The world of Syrphidae