False Star-thistle Peacock Fly, Chaetorellia succinea

This fly's eyes and wings got my attention -- then I noticed that incredible appendage. When I submitted these shots to experts for identification,
I opined that it would be great if this fly were ovipositing in this weed and might help to control it. Surprise: this insect was introduced in the
US for exactly that reason: to control the Yellow Starthistle that has been spreading and infesting pastures and grasslands since the mid-1800's.

This species, along with Chaetorellia australis that are hosted by the Centaurea genus of Starthistles are sometimes referred to as Starthistle
Flies. C. australis has long been called the "Starthistle Peacock Fly," so C. succinea gets stuck with the messy name, "False Starthistle Peacock Fly."

C. australis was brought over from southern Europe in 1988. The female will lay up to 240 eggs in the flower head; the larvae will eat and
destroy up to 90 percent of the seeds produced by the plant, thus helping to reduce its hitherto uncontrolled spread in N America.