Does anybody recognize the insect in these photos?
http://www.zefox.net/~bob/bugs_on_alfalfa/bug1
http://www.zefox.net/~bob/bugs_on_alfalfa/bug2
Same bug, slightly different pose. The "flag" on
the hind legs seemed distinctive.

Three of them turned up on a patch of alfalfa plants I'm
trying as a groundcover. Their movements were what caught
my attention; very deliberate and stately, almost like those
of a mantis.

I tried looking through various alfalfa pest galleries, but
nothing came close and I'm not at all sure these are pests.
I didn't see them feeding and their behavior seemed more like
an ambush predator than a prey species.

First noticed them a couple days ago, when one stuck around it
seemed worth a picture or two.

Thanks for reading,

bob prohaska