Deer Flies from Uruguay

Subject: Biting fly
Location: Northern Uruguay
March 30, 2016 11:30 am
Hello. These are driving me crazy. and I finally got some pictures of them. The are pretty aggressive, circle around, then land on a leg and start biting. They produce painful swollen welts. They have been around from early summer through the fall. They appear to be territorial, yet they “hunt me” in pairs.
Any identification would be appreciated.
Signature: Louis

Deer Fly
Deer Fly
Deer Fly
Deer Fly

Dear Louis,
Some of our more sensitive readers might want us to tag your submission as Unnecessary Carnage, but in our minds, blood suckers are fair game when it comes to battling with insects.  Interestingly only female Mosquitoes and Horse Flies flies suck blood, and the same holds for your Deer Flies in the Subfamily Chrysopsinae, relatives of Horse Flies in the family Tabanidae, like your individuals.  Males and females both feed on nectar, but females need blood before they are able to produce eggs.  Were you painting?  Was it oil or resin based paint?  We understand that some Beetles are attracted to fumes from paints and other solvents, but we don’t know if some Flies are similarly attracted.  You can get more information on Deer Flies on the Orkin site.

Four Deer Flies
Four Deer Flies

1 thought on “Deer Flies from Uruguay”

  1. Have to agree with your sympathetic response. When we lived in northern BC Canada there were biting flies and other insects that were impossible to ignore… large, painful bites. We used to say they flew in with knife and fork and cut off a chunk and packed it away. Especially unwelcome when young children are involved.


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