This is the peak of the deer fly season. If you live near sandy soil, you already know.
Every year this time I think of a story my late friend John Farrow once told me. He said that during the late 1920's deer flies were so bad here along the Cypress that they had to change their farming practices. He said that his dad used mules to plow the fields and to do so, he'd have to soak blankets in kerosene for the mules and wear heavy overalls to keep them at bay. He said his dad had actually plowed the fields under the full moon to avoid them.
The deer fly (yellow fly, stouts, or some names not allowed on a family blog) are a member of the horse fly family and are common around sandy wetlands and forest areas. Their breeding season is May/June and the females are voracious and persistent blood suckers (male deer flies actually eat pollen). Their bites are extremely painful and usually leave welts that will itch for hours afterwards. The bite can prove dangerous as the flies vector tularemia, anthrax, and loa loa filariasis.
Repellants work with limited success but prevention can be as simple as long sleeves and a wide brimmed hat. John used to break off leafy branches and fan them overhead with surprising success. I see today that some entrepeneur is marketing a "trap" for them that consists of an adhesive mesh that you put on the top of your cap or hat.
Thankfully their season lasts only about a month and though a few will remain during the summer, the swarming infestations of them will subside in a few weeks.