Paul Talbert wrote:

>Many years ago on a rafting trip down the Selway (?) River in Idaho we
>were plagued by deer flies and horse flies, and by these
>terrifying-looking wasps that dive-bombed us. After a short while we
>realized that the wasps were hunting the flies and would very neatly lift
>the flies off our arms before they could manage to bite us. The wasps
>themselves were very accurate and hardly even brushed against us. It has
>been too long for me to remember what the wasps looked like, but they
>sound exactly like the horse guards. Since there were no horses in our
>rafts (but there may have been some in the vicinity), I am wondering what
>the distribution of horse guards is and whether they have relatives who
>live in more wild habitats. My foggy memory remembers this raft trip as a
>wilderness experience, but there may well have been ranches in the area
>that contributed to the healthy populations of flies and wasps. The whole
>experience enhanced my appreciation of wasps considerably!

My guess is that these too were sand wasps, family Sphecidae, tribe
Bembicini, probably genus _Bembix_; surely a different species than the one
from Florida. They nest in burrows in sandy areas, including river banks,
and all of them capture flies. They can be frighteningly common buzzing
around just above the ground in sandy areas, but apparently they won't
bother you if you don't bother them.

I'm sure some birds must eat them (bird-related thread).

Dennis Paulson, Director phone 206-756-3798
Slater Museum of Natural History fax 206-756-3352
University of Puget Sound e-mail dpaulson at ups.edu
Tacoma, WA 98416