Western Horse Fly (Tabanus punctifer)
Found this specimen in the parking lot at Marketplace in Friday Harbor yesterday. Glad I didn’t turn into the “grabber” I can sometimes be and instead used a box to scoop up my big find. Probably if you were watching me, you’d have been scratching your head wondering WHY is this woman going through her grocery sacks and opening a snack box of tuna? That box made an excellent fly “trap!”
Big is an understatement! This is the LARGEST fly I’ve collected on the island. It measures over 1 inch long or more than 2 cm. The Western Horse Fly (Tabanus punctifer) can bite through your clothing, although it is the female that needs a blood meal (males feed on nectar and pollen). The adult female lays egg masses (over 300 per mass) on vegetation along ponds and lakes. When the eggs hatch, the larvae develop in the water and here is what I read about them from my sources at Bugguide.com…
“These larvae are aquatic. They have mouthparts that are identical to those of rattlesnakes in structure. A pair of hollow fangs that are connected to a poison/anaesthecic salivary gland further back in the body. These mandibles can easily break through human skin and inject the immobilizing contents of the salivary glands. Normally used to paralyse, and perhaps digest, prey. They are capable of quickly immobilizing/killing animals as large as frogs. They are strictly carnivores and eat ‘meat’.”
I guess this means that the toe-biters aren’t the only ones you should avoid when you go for that swim!
If you care to read more, I suggest this excellent informative guide I found online. It is a 1921 publication from Sanitary Entomology: The Entomology of Disease, Hygiene and Sanitation ~ https://play.google.com/books/reader?id=eIQoAAAAYAAJ&printsec=frontcover&pg=GBS.PA237