GeorgeWS's picture

Giant Wood Wasp

Observed: 21st September 2009 By: GeorgeWSGeorgeWS’s reputation in InvertebratesGeorgeWS’s reputation in Invertebrates
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42mm long waisted fly/wasp. Fell from a tree (species unknown) in an urban environment.

    Likely ID
    Giant Wood Wasp, Horntail (Uroceras gigas)
    Confidence: I'm as sure as I can be.
    ID agreements (): 8 People
    • charlieb
      Lincolnshire Naturalists' Union
      Invertebrates expert
    • Rob ColemanInvertebrates expert
    • Matt Smith
      Amateur Entomologists' SocietyBees, Wasps and Ants Recording SocietyDipterists ForumPeople's Trust for Endangered SpeciesTachinid Recording Scheme
      Invertebrates expert
    • Topsi
      Amateur Entomologists' Society
      Topsi’s reputation in InvertebratesTopsi’s reputation in InvertebratesTopsi’s reputation in Invertebrates
    • ChrisR
      Amateur Entomologists' SocietyDipterists ForumNatural History MuseumTachinid Recording Scheme
      Invertebrates expert
    • Martin Harvey
      Berkshire Moth GroupFSC - Field Studies CouncilSoldierflies and Allies Recording SchemeBuckinghamshire Invertebrate Group
      Invertebrates expert
    • GentalisGentalis’s reputation in InvertebratesGentalis’s reputation in InvertebratesGentalis’s reputation in Invertebrates
    • MickETalbotMickETalbot’s reputation in InvertebratesMickETalbot’s reputation in InvertebratesMickETalbot’s reputation in InvertebratesMickETalbot’s reputation in InvertebratesMickETalbot’s reputation in Invertebrates
Species interactions

No interactions present.


woodyforres's picture


Woodwasps lay their eggs generally in freshly sawn logs, generally about 3cms deep.I think they take about 3 years to develop.


Syrphus's picture

Despite what you might expect

Despite what you might expect from the (perfectly correct) English names, U. gigas is neither a wasp nor a fly, but a sawfly. As such, the 'tail' is not a sting, but an ovipositor.

Interestingly, even when one knows this, it is astonishing how much mental effort is required to pick up unprotected a large yellow-and-black insect with an evil-looking spike at the rear. Some atavistic instinct still lingers!



recording wildlife with The Recorder's Year on

tootsietim's picture

possibly with good cause.

I worked in a woodyard for several years and tried to teach my fellow workers that these beautiful insects are harmless.
Unfortunately, one of my colleagues felt something digging into his shoulder one day, and when I looked, it was one of these, apparently probing his shoulder through his shirt to find a suitable place to oviposit.
Whether his being covered in sawdust made her think he was a living tree I can't say.

Martin Harvey's picture


I've only seen this spectacular insect a few times, but once I took a live specimen to a kids' bug-hunt event, and they were very impressed at my fearlessly picking up such a scary-looking creature!

Entomologist and biological recorder