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For Insects, Spiders & Their Kin
For the United States & Canada
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Genus Toxomerus

Toxomerus Hover Fly - Toxomerus geminatus - female spy fly - Toxomerus marginatus Dipterid - Toxomerus geminatus - female ID, Syrphidae Toxomerus geminatus, flower fly? - Toxomerus geminatus extremely small hover fly? - Toxomerus marginatus - female Hoverfly - Toxomerus politus Toxomerus boscii? - Toxomerus boscii Syrphidae - Toxomerus geminatus
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Diptera (Flies)
No Taxon ("Aschiza")
Family Syrphidae (Hover Flies)
Subfamily Syrphinae
Tribe Syrphini
Genus Toxomerus
Synonyms and other taxonomic changes
Mesogramma Loew 1866, Mesograpta Loew 1872
Moved to Syrphini per recent paper
Explanation of Names
Toxomerus Macquart 1855
From Greek toxon 'bow' + meron 'thigh' (refers to the bow-shaped hind femur)
14 spp. in our area(1)(2)(3)
5-13 mm
Key to species in our area in (4)

Pattern on abdomen is characteristic(5); look for a v-shaped notch on the back margin of the eye.

Colors vary with overall temperature during pupation: if it was hot, the yellow/orange increases and the background becomes lighter, but if it was cold, the dark/black increases and the yellow/orange becomes darker like the background.

"extremely diverse in the tropics with many, many undescribed species and over 100 described species." -Jeff Skevington

Larvae and puparia are bright green.
T. marginatus: much of the US & so. Canada; common
T. geminatus: e. NA; common
T. politus: so. Canada to Argentina; uncommon
T. occidentalis: w. NA; common
10 spp. in Florida
Larvae of most species feed on aphids; although there may be a few that have switched to pollen feeding.
Adults feed on nectar and also pollen.
Life Cycle
Eggs are laid singly on plants near aphids. Presumably late-instar larvae overwinter. Pupation is in soil cavities in spring; adults emerge in summer.(5)
Egg laying
See Also
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.Toxomerus mutuus
3.A Catalog of the Diptera of America North of Mexico
Alan Stone, et al. 1965. United States Department of Agriculture.
4.Field/Photo ID for Flies: Fly Guide
5.National Audubon Society Field Guide to Insects and Spiders
Lorus and Margery Milne. 1980. Knopf.