Subsequent to the handbook I transferred it to Trypanaresta, which more recently is a synonym of Plaumannimyia.
Ref: ALLEN L. NORRBOM, BRUCE D. SUTTON, GARY J. STECK & JOSÉ MONZÓN. 2010. New genera, species and host plant records of Nearctic and Neotropical Tephritidae (Diptera). Zootaxa 2398. (http://www.mapress.com/zootaxa/2010/f/z02398p065f.pdf)

Moved from Trupanea.

I'm using the name from Foote's handbook until I find out more about the new classification.

This is Plaumannimyia flava (Adams). The larvae feed in Baccharis.

...with her (conical) ovipositor everted from inside the tip of the abdomen. Here's a photo of another Tephritid ovipositing .

There's a nice (though somewhat dated) resource for us Californios, namely: "The Fruit Flies or Tephritidae of California", published in 1963 by Foote & Blanc (downloadable as a PDF here). The keys are rather tricky, but the figures at the end of the monograph (pp 108-117) show wing patterns. Many are fairly distinctive and can almost be used to "wing-it" to species. Well, maybe at least to a decent guess...I'm no expert, and Martin Hauser (who is) has warned that these are often difficult to get to species, even with a specimen in hand. Also, names and taxa may have been moved around since 1963.

Nevertheless, taking a stab at it anyway, based on those figures my best guess is Trupanea californica.

PS: Nice shot! (How do you get them so crisp & clear?:-)

Moved from Flies.