I've received a really interesting response on my black fly post. It came from a friend's daughter-in-law, Whitney, who has had similar bad experiences as I have. Here's what she wrote:

OFF! (even the deep woods stuff!)  tends to have too little DEET in it.  It is not effective for me.  I need in the 90's (98% and higher seems to work most of the time, especially if there are other victims not using anything).  It's a vile, toxic, awful substance, but better for me than the intense itching.  Repel is good, which is what I use, and Benadryl ES [if bitten, to stop the itch].

The itching is not directly caused by [the anticoagulant the insect injects], but rather, a reaction to its existence in the body.  The itching, welt, swelling, heat, hives, is all caused by histamine.  Histamine is produced by the body, typically in reaction to a foreign substance invading the body (such as an anticoagulant's proteins).  For some people, the body produces just enough to neutralize the perceived threat.  For others, the body goes into overtime and throws way more at it than it seems necessary for anyone else.  For me, one mosquito bite will result in hard, swollen, hot, red lumps that itch almost relentlessly for two weeks and the itchiness increases to an unbearable level every so many hours.  The more of these I get, the worse they feel, especially when whatever my body does every x hours hits.  They will all react at the exact same time and I get hot all over and the itch spreads internally where I cannot scratch.  I have perceived that most people do not get it this bad, and some get it worse - such as hives breaking out over their bodies, too.

My regimen before going outside longer than a few minutes with immediate escape available, if I'm not wearing a bug net over my entire body:  Repel (98.1% DEET) ALL OVER exposed skin, on my hat, around the edges of hat, smoothed onto hair, and lightly smoothed onto clothing all the way down to socks and shoes.  If I still get bitten, I carry Mometasone Furoate (prescription) for ear eczema which must be applied right away, and that nixes it.  I used to try Benadryl Extra Strength cream and at the time, it failed miserably... but the other night it worked when someone gave me some for a bite on a finger of all things.  So that may be an option for me again which is good because the MF isn't doing what it used to (it's expired, too, which makes me think my Benadryl ES had been, too).  Benadryl is an anti-histamine, which when it soaks into the skin, neutralize's the body's reaction.  MF is a topical steroid that reduces swelling - how, I'm not sure, but it neutralizes the itch so it must work somewhat similiarly.  Steroids (even topical ones) are generally frowned upon for heavy use in the same area because it thins skin.  However, I do not care.  The suffering from bites is, well, insufferable, and as an adult, I've stopped caring about all the new-age worries about the environment and frogs and health effects caused by poison.  I went unbelieved - even scoffed at, was given advice that never helped (don't scratch it makes it worse), etc - way too long to listen to anyone anymore.  I finally found what works for me, and now I laugh inwardly when I'm walking with my bug gear on in deep woods, lightly covered in DEET, carrying my anti-itch stuff, being laughed at at first... then seeing everyone scratching and swearing and giving me jealous glances.  Yeah.  That was me for thirty something years.  Only I had worse welts than they're getting.  They can byte me.  But they won't, because they're anti-poison.

I like the way she thinks! I went outside today for about an hour, all bundled up with one of those nets like bee keepers use tied tightly over my upturned shirt collar - cuffs of my long-sleeved shirt tightly buttoned and rubber bands cinching my pantlegs over my socks. I had smeared Crocodile on my face before I put on all the garb and felt pretty confident I was safe. That was mostly true - I got only one bite - on my hand. I was using the lawn mower and was moving all the time, so I didn't think I needed gloves. Wrong! I was bitten on my hand so now I have a big hot, red, itchy welt on my knuckles.

While the rest of me was safe and the black flies lined up all over the netting over my face, they couldn't get to me. But I darn near collapsed do to being over-heated. So I had to come in before I'd really accomplished as much as I'd hoped and shed all my tight coverings and enjoyed a cool shower. I will try Whitney's suggestions. It would be great to be able to work outside and not be eaten alive.

We have some rain coming tomorrow and a little each day all next week, looks like. I suppose when the weather finally turns around we'll be complaining about the heat and dry conditions. I was going to look at our old apple tree while I was outside this afternoon. It seems to be later than usual with blossoming. Our crabapple is just beginning to bloom and will be at peak in another day or two, and they usually bloom at about the same time. We have a service berry bush on the lower lawn that has been loaded with flowers for about a week; but the old apple tree seems to be resisting again this year. Usually if it misses a year blooming, like it did last year, the next year it will be loaded. Maybe it's just a late bloomer. We'll see. 

We had some motorcyclists pass by here this morning. I think there were eight or ten of them - I expect they were taking some sort of special "scenic tour" that would take time up to the Plain Cemetery and Foster Bridge. The view wouldn't have been great today - too hazy. According to Gary Sadowsky on WCAX, the haze is due to some forest fires in western Canada. Their weather has been hot and dry this spring and the fires have mostly been started by lightning strikes. Last year California, this year Canada. They get fires, U. S. gets floods and tornadoes. And now the hurricane season is beginning. "Troubles come not singly but in battalions," to paraphrase Shakespeare.