Thick-headed Fly - Stylogaster

This is definitely a male

...from the truncate abdomen (females have a conspicuous ovipositor). If the relative length of the last (3rd) antennal segment to the preceding (2nd) could be discerned, then an unequivocal ID to one of the two US species could be made.

… Aaron Schusteff, 29 October, 2012 - 12:33am

Color

According to Aldrich (1930) the thorax of male biannulata is largely yellow and of neglecta is black.

… John F. Carr, 13 February, 2014 - 7:16am

Thoracic color and species

John, I just reread the descriptions in Aldrich, and your point is well taken.

But I'm hesitant to go on that alone, as Williston's 1883 description of S. biannulata here states the male of that species has "dorsum of thorax black"...which seems to contradict Aldrich's 1930 description, which states: "Thorax yellow, the dark mesonotal spot smaller than usual, well-defined, widely separated from lateral margins and deeply notched behind".

Apparently, Aldrich redescribed the species based on 6 males and 14 females...and when Williston wrote in 1883, the circumscription of the two nearctic species may have been less clear. I don't know for sure, and unfortunately we currently don't have any positively ID'd images of male S. biannulata with which to cross-reference.

That said, this may likely be S. neglecta, if for no other reason than that it's the more common of the 2 currently described species...though Jeff Skevington indicates there's a nearly finished paper introducing a new nearctic species in his recent comment under the post below (which is from far west of any other Stylogaster posts to date):

… Aaron Schusteff, 14 February, 2014 - 6:32pm

Thanks,

John, for that additional info. So this one is probably S. neglecta?

… Nancy Kent, 13 February, 2014 - 7:41am

Thanks,

Aaron, I appreciate that explanation.

… Nancy Kent, 2 November, 2012 - 8:27pm

Moved

Moved from Flies.

… Keith Bayless, 23 February, 2011 - 12:02am

Thanks!

Thanks, Keith!

… Nancy Kent, 23 February, 2011 - 6:10am

Moved

Moved from ID Request.

… v belov, 19 February, 2011 - 3:55pm

look in the Conopidae [not an ID]

… v belov, 10 February, 2011 - 2:04pm

I tried that but....

I tried that but have not found a match:(

… Nancy Kent, 11 February, 2011 - 7:23pm