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Genus Macrosiagon

Beetle - Macrosiagon cruenta unknown - Macrosiagon octomaculata - female Macrosaigon cruentum cruentum (Germar) - Macrosiagon cruenta - female  Wedge-shaped Beetle - Macrosiagon limbata - female Ripiphoridae - Macrosiagon limbata Macrosiagon limbata Yellow and black beetle - Macrosiagon limbata Rhipiphoridae? - Macrosiagon
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Polyphaga (Water, Rove, Scarab, Long-horned, Leaf and Snout Beetles)
No Taxon (Series Cucujiformia)
Superfamily Tenebrionoidea (Fungus, Bark, Darkling and Blister Beetles)
Family Ripiphoridae (Wedge-shaped Beetles)
Subfamily Ripiphorinae
Genus Macrosiagon
Explanation of Names
Macrosiagon Hentz 1830
Greek 'large jaw' --refers to the enlarged mouthparts:

The grammatical gender is feminine, thus the -a endings of the specific epithets. (Zack Falin, pers. comm. to =v=, 21.xii.2009)
the largest genus in the family, with 11 spp. in our area and ~160 worldwide(1); 7 spp. in NC & SC(2)(3), 8 in FL(4), 2 reach Canada(5)
4-12 mm
Elytra cover most of abdomen. Thorax has projection covering scutellum. Usually colored black and orange. In females, abdomen blunt, antennae mostly serrate; in males, abdomen more pointed, antennae pectinate. Color varies greatly within species.
keys and descriptions in(6)(7)(8)
Worldwide; in NA, much of the US + ON & SK(1)(5)
adults usually on flowers, esp. Asteraceae(1)
Larvae are parasitoids of wasps and bees (Vespidae, Sphecidae, Crabronidae, Pompilidae, Apidae, etc.) +Host associations: M. cruenta, twig-nesting Eumeninae; M. flavipennis, Bembix; Scoliidae, Tiphiidae(9); hosts in Cuba, Indonesia
Life Cycle
Internal parasites of bees and wasps. Females lay eggs on flowers. Eggs hatch into an active larva called triungulin (three nails or claws) that attaches itself to visiting wasp or bee. It is carried back to wasp nest where it burrows into a host larva.
our only representative of the tribe Macrosiagonini Heyden 1908(1)
Internet References
Works Cited
1.American Beetles, Volume II: Polyphaga: Scarabaeoidea through Curculionoidea
Arnett, R.H., Jr., M. C. Thomas, P. E. Skelley and J. H. Frank. (eds.). 2002. CRC Press LLC, Boca Raton, FL.
2.Insects of North Carolina
C.S. Brimley. 1938. North Carolina Department of Agriculture.
3.Tenebrionoidea of South Carolina
Janet C. Ciegler. 2014. Clemson University.
4.A Distributional Checklist of the Beetles (Coleoptera) of Florida
5.Checklist of beetles (Coleoptera) of Canada and Alaska. Second edition
Bousquet Y., Bouchard P., Davies A.E., Sikes D.S. 2013. ZooKeys 360: 1–402.
6.Revision of the Rhipiphoridae of North and Central America
Ezekiel Rivnay. 1929. American Entomological Society.
7.A review of the genus Macrosiagon in Mexico, with notes on Rhipiphorus (Coleoptera, Rhipiphoridae)
Patricia Vaurie. 1955. American Museum of Natural History.
8.The Rhipiphoridae of California (Coleptera)
Linsley E.G., MacSwain J.W. 1951. Bull. Calif. Insect Surv. 1: 79-88.
9.The Wasps
Howard Ensign Evans, Mary Jane West Eberhard. 1970. University of Michigan Press.