Wanted to see if any of y'all have had a similar situaton. Went out to our property along the Trinity in Navarro county looking for hogs this weekend. Was wearing long sleeves and pants, sprayed with DEET. A little while after the sun came up I kept getting swarmed..... and i mean swarmed,by these small flying insects that bit like crazy. I knew they weren't mosquitoes however I didn't know what they were. Did a quick google search and found what I think is the culprit, a species of black fly. It seems like these rains and flood waters have been perfect for them, they bite and itch like crazy, just wondered if y'all had encountered them and found something that works to keep them at bay?

I don't see how the deer can stand them.

Deer have fur and I doubt the gnats can get through it, or want to.
In freestone Co. just southeast of you they showed up about 10 years ago and they suck. I spent the last 2 weeks sheltering in my country place and while they annoyed me, I wasn't bit but my daughter was a few times. I have been bitten before though. OFF doesn't seem to bother them enough. Let me know what your solution is to them so I can follow suit.

They seemed to have shown up about 4 years ago at our place up north near Wichita Falls. I hate them.
People seem to react differently- many just get a stinging itchy burn. Others well up like crazy. My wife is the former, I am the latter.
I've taken to wearing a bug shirt- built in mesh hood. DEET doesn't affect them, I tried a "natural" version that I found at Academy and it only helped a little.
Some people swear by natural Vanilla- rubbed on full strenght. Can't be artificial vanilla- has to be natural. For me it didn't work- just made me smell good.
I have had a little success using dabbed-on Campho-Phenique.
They suck. Hate them.
Buffalo Gnats

Try fishing Canada in July, you'll find out real quick why Caribou are always moving, you can see them coming across the water in clouds. Migrating my Aunt Fanny, they're running for their lives!
They can at least get in the water and get relief, you jump in the water and come up with leeches. Everything nth of the American border want's you blood!

But Damn! It's some good fishing.

We were fishing on Lake Sassagenagak in Manitoba 25 years ago, my first Canadian fishing trip. Typical Texan I'm on the lake in shorts and a t-shirt. Spotted a small cove that just said "Big Northern", on my second cast the swarm hit us. I've never experienced anything like that before, you couldn't breath without sucking them in. I pulled my t-shirt up to cover my mouth and nose only to expose more of me to them little biting bastard. The bite's wasn't as bad as the itching that followed. In the mountain area's the Caribou move up to the snow patches to get away from them.

We haven't even started on the subject of mosquito's. Like P-51 Mustangs but with more firepower and lifting capacity.

Not sure what you got into but Black Fly is very tiny and there are few thing that will ward them off. I ran into them in the UP of Michigan. They came out near sunset and would wear your A$$ out.

I had a run in with them in Wichita Falls area 20 years ago. They left big , itchy welps on my neck and scalp.

This is what we got into.

Dealt with them damn things in North Dakota for 3 years . There was no escaping them when fishing.

These stories make me never want to go fishing in the spring again. Crazy amount of bugs