thank you for identifying this lovely monster Tony, if only i could get pictures as good as yours...

Thanks, Tony, for the info and encouragement. My car, aka Mazda Theater for Performing Insects, has red paint with mica flecks to attract beetles and such, but apparently I need something more macho to draw the big flies. I've long envied your full front facial fly photos and hope I can get some of the same.

will work but it is a lot cheaper to use a large sheet of shiny black polyethylene. Simply drap it over the Mazda, hang it from a tree or support it by a couple of poles. Perhaps the best attractactant, even better than an F305, is a shiny black beach ball or excercise ball as large as possible.
If you type tabanid + traps into Google search window you will see many designs for tabanid traps.

Now I can buy more camera gear. I'll take your tip on traps; thanks again.

here.

I printed the need-to-know-for-now stuff and bookmarked the site. It's amazing how much good info is online.

The females do require the blood of a mammal. And it can be from dense deer populations as well as likestock. I've found the cows out in the field much better attractors than the stabled animlas though a cowgirl here in my state keeps a large bug zapper in her horse stall and has buckets of specimens during the summer.

The Stictia colony of horse fly catching wasps at Holla Bend NWR is located on a sand stretch just east of a cow pasture. Horse flies are indeed abundant near there. And I have had the wasps take horse flies out of the air that were making electron patterns around my head.

Male horse flies are generally rarely seen animals anywhere. They can be high flying and solitary. When freshly born in the world they often go to water and I have caught some there before at the edges of creeks and ponds.

Thanks for the info, Herschel. When I moved to Orange County, CA thirty some years ago, we had many more flies. There were a lot of cows here then, but no longer. Same goes for crops. I should have started photographing insects earlier.

when talking about insects. Just to keep the science correct and not meant as a criticism: most tabanids require blood to develop eggs but some species do not, these species are termed autogenous. The autogenous species are normally seen only on flowers.

I know nothing about these flies compared to Tony. I know that autogenous species in NA are not the norm. And though I have read some papers on Tabanid blood feeding in dealing with transfer of human diseases I have not read the detailed papers on sugar and heme content in eggs and ovarian dissection. These may be beyond my somnolence capabilities in my advancing age.

The majority of our female horseflies immediately seek blood on emergence. Some cannot produce viable offspring without blood meals. Some can. It is not clear that those proven to be capable of fertility without blood do not also blood feed at some part of their adult cycles. I believe all of our species in the east have mouthparts which would allow blood feeding. It is my understanding that virtually all horseflies of either sex appreciate a nice nectar source otherwise. And elsewhere in the world are some genera that don't need blood at all ever to fulfill their life cycles. They are pure nectar users. Oh if only all the Chrysops only used nectar.

you know... i have no idea, i rarely see them, and i live near people who own cattle, and i think there are a few horses around. i seem to find more deer flies, or other smaller tabanids, but never get good pictures of them... this thing, however, was a monster, and did not mind posing.

...I will try wearing a pony tail. Will let you know what happens.

a potentially painful experiment... do keep me posted.