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Mating pair of therevids - Ammonaios confusus - male - female

Mating pair of therevids - Ammonaios confusus - Male Female
At base of Chalk Bluffs, near Pleasant Valley Campground, Bishop area, Inyo County, California, USA
August 8, 2017
Found in late afternoon resting in the shade on a large chunk of volcanic rock (welded tuff), a bit above the base of Chalk Bluffs just north of the Owens River. This mating pair stayed absolutely motionless for quite some time while I walked back to the vehicle to get my camera, and also for many minutes more after I returned. Then all of a sudden it darted off in a flash, spooked by some relatively minor movement compared to our proceeding movements while positioning to get photos.

Appeared to be a therevid in the field, and though I couldn't positively verify all the characters in keying it to family in the MND(1), it did seem to go best to Therevidae.

Similarly, in the MND(1) key for family Therevidae, I don't have enough detail in my photos to navigate all the detailed character couplets...but going "both ways" at unclear junctures, the best candidate I got was Ammonaios. And consulting:

Hauser, Martin & Michael E. Irwin (2003). The Nearctic Genus Ammonaios Irwin and Lyneborg 1981 (Diptera: Therevidae). Ann. Entomol. Soc. Am. 96(6): 738-765. (Full Text) best guess would be A. confusus, which also has nearby records (e.g. at Fish Slough).

Alice Abela also got some photos of the pair before it darted off, perhaps hers may show more diagnostic characters.

Images of this individual: tag all
Mating pair of therevids - Ammonaios confusus - male - female Mating pair of therevids - Ammonaios confusus - male - female

Moved from Stiletto Flies.

Moved from Flies.


female face (I couldn't get close from this angle)

If there are additional angles you need, let me know and I'll see what I have :-)

Great! Thanks, Alice :-)
The full-size versions of your two photos show critical details for various additional diagnostic characters.

Studying your images, most of my lingering doubts about various character-state choices in the MND(1) keys to family and genus are clarified. In particular, these are definitely Therevidae (which we already strongly suspected in the field, though I was unable to clearly discern and verify a few minor technical characters while going through the family key earlier).

And using your photos, the MND key to genera for Therevidae seems to lead fairly clearly to genus Ammonaios (or possibly, but less likely, Arenigena)...see my comment under your profile shot for more details.

Nice that you got a frontal shot of the female (whereas my frontal shot showed the male).

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