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Species Megacyllene robiniae - Locust Borer

longhorned beetle - Megacyllene robiniae Megacyllene robiniae not a bee or wasp? - Megacyllene robiniae Insect found in Reston, VA - Megacyllene robiniae Locust Borer - Megacyllene robiniae Locust Borer? - Megacyllene robiniae Locust Borer? - Megacyllene robiniae Pennsylvania Cerambycid  - Megacyllene robiniae
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 Chrysomeloidea (Longhorn and Leaf Beetles)
Family Cerambycidae (Longhorn Beetles)
Subfamily Cerambycinae
Tribe Clytini
Genus Megacyllene
Species robiniae (Locust Borer)
Explanation of Names
Megacyllene robiniae (Forster 1771)
robiniae = 'of Robinia' (refers to a host tree)
11-28 mm(1)
all elytral markings yellow (1)
metepisternum (region between 2nd & 3rd hind leg) nearly completely covered in yellow pubescence (2)
widely distributed, wherever people have planted Black Locust (Robinia pseudoacacia).(3)(1)
Adults common on flowers of goldenrod (Solidago) Aug-Oct
mostly Aug-Oct (BG data)
Larvae feed on Black Locust (Robinia pseudoacacia). Honey Locust (Gleditsia triacanthos) is not affected.
Adults feed on pollen, particularly goldenrod (Solidago spp.).
Life Cycle
Eggs are laid in the fall. Newly emerged larvae hibernate under bark, tunnel in spring, making tunnels about 10 cm long and 6 mm wide, pupate late Jul/early Aug; adults emerge late Aug-Sep.
Larva & pupa
Considered a serious pest of Black Locust; previously weakened or damaged trees are often killed by the larvae. Previously confined to the native range of Black Locust in the northeast, it has spread with the trees throughout the US and parts of Canada. Black Locust is used for reclamation and similar projects where trees are likely to be stressed and thus more vulnerable to damage.
See Also
Hickory Borer (Megacyllene caryae) is active mainly Mar-May, and its elytral bands typically alternate yellow and white:

Mesquite Borer (Placosternus difficilis) is confined to southern US, and sutural one-third of elytron has distinct, abrupt depression margined by a slight carina (or ridge) (2)
Internet References
Utah State Univ. Extension (Karren & Roe 2002)
Works Cited
1.Field Guide to Northeastern Longhorned Beetles (Coleoptera: Cerambycidae)
Douglas Yanega. 1996. Illinois Natural History Survey.
2.Illustrated Key to the Longhorned Woodboring Beetles of the Eastern United States
Steven W. Lingafelter. 2008. Coleopterists Society.
3.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.