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Species Mydas clavatus

Mydas clavatus Mydas Fly - Mydas clavatus Mydas Fly - Mydas clavatus - male Stizoides renicinctus? - Mydas clavatus large black and orange wasp - Mydas clavatus - female Looks like a Spider Wasp (Anoplius viaticus - found in Europe). It was in my vegetable garden in West Boylston Massachusetts  - Mydas clavatus Mydas clavatus Mydas clavatus
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Diptera (Flies)
No Taxon (Orthorrhapha)
Superfamily Asiloidea
Family Mydidae (Mydas Flies)
Subfamily Mydinae
Genus Mydas
Species clavatus (Mydas clavatus)
Other Common Names
Clubbed Mydas Fly
Synonyms and other taxonomic changes
Mydas clavatus (Drury, 1773)
Explanation of Names
Latin clavatus, clubbed; refers to clubbed antennae
length 25-30 mm; wingspan 50 mm or more
Large black fly with red/orange mark on top (dorsum) of 2nd abdominal segment. Body hairless, cylindrical. Eyes large. Antennae are distinctively clubbed in the Mydidae. This species flies rather boldly in the open. With the black-and-orange pattern, it resembles a wasp and fools the casual observer.
eastern half of United States and southern Ontario
Deciduous woodlands, fields, meadows, gardens, shrubby borders, open areas.
June-August (North Carolina)
Adults sometimes found on flowers, presumably taking nectar (based on guide images).
An old (1930) Ohio State U. source says "The mouthparts of the Mydas fly have been worked out and figured by Peterson (1916), and present a type of structure similar to that in the robber flies and horse flies, but distinctly less specialized. This is another evidence of the predaceous method in acquiring food, although there is no record which shows that the adult Mydas fly has ever been observed actually attacking another animal." The same source makes the assumption that Mydas clavatus is carnivorous because it has a relatively short alimentary canal.
A more recent U. of Arkansas source says "Adults were long presumed to be predaceous, but the lack of mandibles along with other features of mouthpart morphology and observations of flower feeding tend to indicate that they consume nectar."
Larvae of Mydas clavatus feed on larvae of beetles in family Scarabaeidae.
Life Cycle
Eggs are laid singly in soil or rotting wood. (See video of oviposition--Flickr). Mydas larvae prey on beetle larvae, esp. those of June beetles. Larvae pupate close to soil (or wood?) surface. Illustration of larva and pupa:
Adults are active only in mid-summer. Mating system in this species unknown. Different Mydas species apparently have different mating systems, including resource-defense polygyny and "hilltopping". See Preston-Mafham (1).
Personal observations (Patrick Coin, July 2015, Durham NC--here) seem to indicate males of this species stake out oviposition sites and mate with incoming females--resource-defense polygyny.
Batesian mimic of certain spider wasps (Pompilidae), e.g., Anoplius:
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See Also
Print References
Arnett, American Insects, p. 876 (2)
Borror and White, plate 13 (3)
Brimley, p. 335 (4)
Cooper, W. E. (1981). Mimicry and spatial occupation of the mydas fly, Mydas clavatus. J. Alabama Acad. Sci. 52(2): 58-65 (Full Text)
Deyrup, p. 135--color photo (5)
Gibson, W. W. (1965). An observation on the oviposition habits of Mydas clavatus (Diptera: Mydaidae). J. Kansas ent. Soc. 38(2): 196-197
Milne and Milne plate 459 (6)
Swan and Papp describe and illustrate the adult, larva, and pupa (fig. 1303) (7)
Williams, A. H. (1995). Adult female Mydas clavatus (Diptera:Mydidae) feeding on flowers in Wisconsin. The Great Lakes Entomologist 28(3-4): 227-229. (Full text beginning on pg. 31 of this PDF)
Zaitlin, L. H. (1978). Morphology of the Head and Mouth Parts of Mydas clavatus Drury (Diptera: Mydaidae). PhD Thesis. University of l1linois at Urbana-Champaign. 216 pp.
Zaitlan, L. M. & J. R. Larsen (1984). Morphology of the head of Mydas clavatus (Diptera: Mydidae). Intern. J. Insect Morphol. Embryol. 13(2): 105-136.
Internet References
The Internal Anatomy of the Mydas Fly; PDF doc (Lydia Jahn, Ohio State U., 1930)
Works Cited
1.The Encyclopedia of Land Invertebrate Behaviour
Rod Preston-Mafham, Ken Preston-Mafham. 1993. MIT Press.
2.American Insects: A Handbook of the Insects of America North of Mexico
Ross H. Arnett. 2000. CRC Press.
3.A Field Guide to Insects
Richard E. White, Donald J. Borror, Roger Tory Peterson. 1998. Houghton Mifflin Co.
4.Insects of North Carolina
C.S. Brimley. 1938. North Carolina Department of Agriculture.
5.Florida's Fabulous Insects
Mark Deyrup, Brian Kenney, Thomas C. Emmel. 2000. World Publications.
6.National Audubon Society Field Guide to Insects and Spiders
Lorus and Margery Milne. 1980. Knopf.
7.The Common Insects of North America
Lester A. Swan, Charles S. Papp. 1972. Harper & Row.