Fruit fly found flying and crawling about in Yellow Star-thistle. The patterned wings and green eyes suggest family Tephritidae. This fly has an interesting terminal appendage.

I will submit five photos and note certain features revealed in each:

-1: dorsal view shows twisted wings and thoracic pattern; all photos show a terminal appendage nearly the length of the abdomen.
-2: lateral view: eyes, halteres; terminal end of appendage looks like round hollow tube.
-3: wing pattern, aristae, etc.
-4: here the terminal appendage has “telescoped” out to double its normal length.
-5: terminal appendage has been extended further, now nearly 3X the length of the abdomen.

The interval between shots 4 and 5 was four seconds, after which the extension was retracted and not seen again. I will tentatively assume this appendage is that of a female, ie, some kind of ovipositor.

Another image reveals that this fly can rotate its head a full 90 degrees.

Note: Yellow Star-thistle, Centaurea solstitialis, is our most noxious invasive plant; it would be a fine thing if this insects’ larvae would help to control it.

Identification, corrections, explanations welcome. Thanks.