Subject: Unusually large fly
Geographic location of the bug: South Wales
Time: 09:12 AM EDT
Your letter to the bugman: Hi there, a very unusually large fly came into my kitchen which I have trapped in a vase alongside a British pound coin to give perspective. I live in a rural location, about 900feet above sea level, there are sheep, cows and horses roaming nearby and it’s an unusually hot summer. Are you able to let me know what this is please?
How you want your letter signed: Kathryn
This is a beneficial, parasitoid Tachinid Fly in the family Tachinidae, a very large and diverse family, and it appears to have a lighter, yellow head, which causes us to believe it is Tachinia grossa. See Diptera Info for an image of that species. Parasitoid insects lay eggs on or near other insects, arthropods, and occasionally other creatures, and when the larvae hatch, they feed on the host. Many Tachinid Flies prey upon caterpillars, and NBN Atlas includes a list of known caterpillars preyed upon by Tachinia grossa, including the Oak Egger or Lasiocampa quercus, the Gypsy Moth or Lymantria dispar and Hemaris fuciformis, a diurnal Hawkmoth.