May 162012

I went down to an inland dune habitat in Southwestern Ontario yesterday with my lab mates to do some collecting. For the most part insects were pretty scarce to come by, except for the biting flies, which were out in abundance.

Chrysops cuclux tasting

Chrysops cuclux making sure I will taste just right

Thankfully this was the only deer fly (family Tabanidae) that I had the misfortune of waiting on. I initially went to brush it off, but when I noticed it was oriented in such a way that I could snag a photo, I bit the bullet and allowed it to continue while I contorted my camera around to document another happy customer.

Chrysops cuclux tasting

It's true; the first cut is the deepest

Unlike mosquitoes, who’s mouthparts act like a hypodermic needle to stealthily imbibe your blood, deer flies cut and slice the skin, causing bloodshed which they then lap up. Much like a skinned knee is usually more painful than the prick of a phlebotomist, a bite from a deer fly will rarely go unnoticed, and in this case, make it all the more difficult to photograph whilst squirming!



If you’re curious, here’s a shot of my arm this morning, about 18 hours after the bite occurred. There was a swollen welt about 1″ in diameter that was quite firm and which occasionally had a strange tingling sensation, yet wasn’t itchy. Things seem to be back to normal 36 hours after the bite, with only a small firm area directly below the bite.

Chrysops cuclux bite after 18hrs

Chrysops cuclux bite after 18hrs, with black fly bites for comparison


If you’ve had a run in with a deer fly before and are curious what species it might have been, check out CJAI #8 (The Chrysopinae of Canada East of the Rocky Mountains) or Tesky’s hand book to the Tabanidae of Canada.

  9 Responses to “Like a Deer Fly in the Headlights”

Comments (7) Trackbacks (2)
  1. I’m glad I’m not the only one! Thank you for inspiring this post:

  2. can identify this bug for me i have pictures its been bitting me and its really bad

  3. For about 10 years now I’ve wondered what has been biting me and causing such atrocious swellings. You sir have just solved that mystery. The picture of your arm and how you describe your bite is exactly like what I have hand on my arms, hands, legs, and (unfortunately) face many times. Thank you for putting a decade-old mystery to rest. I now know which bug to haul ass from as soon as I see it.

  4. Every time I mow my lawn, this fly hits me and I swell and itch. Any one !!! HELP

  5. Thanks for the clear pictures and descriptions here! I am now fairly certain what the mystery insect that took a chomp out of my leg last night was, though I am somewhat surprised to find deer flies in downtown Toronto. Still, I suppose that if they were to move to the city, the overgrown parking lot that I was walking past would be prime real estate to a fly, and passing pedestrians would be tasty takeout.

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