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fly 151 - Polybiomyia - female

fly 151 - Polybiomyia - Female
Garden Canyon, Cochise County, Arizona, USA
September 4, 2013
On Dalea

Images of this individual: tag all
fly 151 - Polybiomyia - female fly 151 - Polybiomyia - female fly 151 - Polybiomyia - female fly 151 - Polybiomyia - female

Moved from Polybiomyia bellardii.

Thinking it's probably best to place this post back under the genus, until doubts expressed in my comment below can be resolved.

Moved from Polybiomyia.

This doesn't really key out in Polybiomyia either. Although I guess it could just be a rather light colored specimen.

It comes out as Polybiomyia bellardi

It lacks prescutellar spots or stripes. It lacks pleurotergital markings. No yellow spots on pleurae. This leaves only two species.
Polybiomyia bellardi and Polybiomyia pedicellata.

Polybiomyia pedicellata has black legs and a 3rd abdominal segment longer than broad. This specimen has red legs and a 3rd segment broader than long which agrees with Polybiomyia bellardi

Edit: When I am in the collection this week. I'll check our holdings and see if I can't give a precise answer.

Edit 2: Upon further research. This keys to Polybiomyia reinhardii described by Hull in 1930. It is considered a synonym of Polybiomyia bellardi. Moving this to that species.

Kevin, what key did you use to get to P. reinardii?
The only key I know of for nearctic Polybiomyia is Shannon(1925)...written before P. reinardii was described. It would be great to know if there are more recent keys!

I strongly suspect this is an undescribed species
The female AZ post here, as well as the nearly identical male from the same general area below:


...both look quite different from the other current TX posts of P. bellardi:


The latter are in excellent agreement with the key & description of P. bellardi in Shannon(1925), which was based on specimens collected in TX...and P. bellardi is also listed as having range "Tex." in Stone(1)(1965), and in this 2005 Systema Dipterorum record.

I wanted to understand this situation better, so I very carefully read Hull's 1930 original description of the female P. reinhardi (on the 3rd page of the PDF here)...cross-referencing the many details there, sentence-by-sentence, with the female in the 4 photos of this post. While some characters seemed nicely compatible with the photos here, many more were not! [Rather than list those details here, I invite you to carefully reconcile the description and photos...I trust you'll see what I mean.] Of course populations can vary within a species, and authors can sometimes be inaccurate in their writing...but, even accounting for that, the degree of discrepancy seemed too large for me to have confidence in an ID of P. reinhardi here.

It then occurred to me that perhaps this female might fit better with the other "new" species, P. festiva, that was described in Hull(1930). Pursuing this, again a number of characters fit well...especially for the head (e.g. reddish medial & lateral stripes on face, w/ black spot below eye, etc.). But may others (e.g. various yellow spots on the pleura) were way off. And both species were described by Hull as having reddish posterior bands on the abdominal terga...whereas those bands are clearly yellow here, as is typical for most species of Polybiomyia.

As you noted, P. reinhardi has been synonymized under P. bellardi (see here); while P. festiva has been synonymized under P. townsendi (see here)...though, as is often the case, it's not clear who established the synonymies or on what basis (they were still listed as separate species in Stone(1)(1965)). Note that each of bellardi, reinhardi, and festiva were described from TX specimens, and Texas was given as the range for each in Stone(1)(1965)...whereas the range given for P. townsendi was: "N. Mex.; Calif., Ariz., Tex." (see also here).

Given the descriptions and the location here, if one were to require an ID based on described species...I'd reluctantly go with P. festiva = P. townsendi as my best choice among the options, though none really fits well enough. As far as I know, there's been no published revision/review of nearactic taxa of Polybiomyia since Shannon(1925), and my best hypothesis is that the female here (along with the male in the first thumbnail above) belong to a currently undescribed species.

Moved from Syrphid Flies.

I see a spurious vein on the wing as well.

Either Sphiximorpha or Polybiomyia - the best character between them is on the underside (of course!), but this doesn't key out in Sphiximorpha at all, so Polybiomyia it is. Alas, I don't have access to a key for this genus, but I hope someone else (Martin?) may be able to key it for us.

Moved from Flies.

Two votes for Syrphidae. Let's see what the experts have to say.

Hm... Conopid or Syrphid?
Leaning toward Cerioidini--but quite prepared to be proven wrong. :)

Wing looks like Syrphidae to me.

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