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Thick-headed Fly - Physoconops

Thick-headed Fly - Physoconops
Mobile (Dog River), Mobile County, Alabama, USA
October 1, 2008
Sometimes I think there are more wasp mimics than wasps. So, which one is this one?

Moved to subgenus Pachyconops
Moved from Physoconops.

Robert, I've been mulling over this one for a long time. I now understand genus Physoconops better than I did back in December of 2013, but I still can't tell whether this is P. excisus or P. brachyrhynchus.

In particular, if I could discern whether the thin, pollinose (= dust-like) yellowish-white stripe along the posterior edge of the head is complete (i.e. continues from behind the eyes and extends behind the vertex as well), then I'd go with P. excisus. That doesn't appear to be the case here, but that character is often hard to see depending on lighting and/or angle of view. And from working on many similar posts, I've begun to wonder if that character is entirely dependable, or if the pollinose dust can sometimes have gotten (at least partially) worn off?

If we had a direct profile view of the cheek, then a dark spot there would also take this to P. excisus (versus a pure yellowish-white cheek for P. brachyrhynchus). And for females, the size of the theca (large vs. small) also separates the two species, when it is visible.

Either way, the relative length of the 3rd antennal segment certainly makes it a member of subgenus it can at least be moved to there.

Moved from Conopinae.

Moved from Physoconops or Physocephala.

Moved to the Conopinae subfamily page...since the only two (continental north of Mexico) genera in the subfamily are Physoconops and Physocephala, so having the "Physoconops or Physocephala" guide page node in the BugGuide taxonomic tree is superfluous.

Moved again...looking more like Physoconops
Moved from Physocephala marginata.

I scrutinized the right wing above, trying to ascertain the position of the cross-vein r-m with respect to the discal cell, so as to double-check whether this is indeed Physocephala (for context, see here). The cross vein r-m appears very close to the middle of the discal cell, indicating Physoconops.

As mentioned earlier, the very long terminal part of the antennae also makes this look like Physoconops to me.

The hind femora do look quite uniform in width, another nod towards Physoconops. (Though I often don't trust this character unless I have a profile view of the femora...since in vertical view the swelling of the basal half of the femora in Physocephala is often not apparent.)

The petiolate 2nd abdominal segment here is mainly reddish, whereas in all the current P. marginata posts it's blackish.

The pulvilli look quite long and pure yellow to me, contrasting strongly with pure black tarsi...again more compatible with Physoconops than Physocephala.

In view of the above, I think the best thing now is to place this post here, and when those with a better expertise in Physoconops see it, hopefully they'll be able to confirm or correct the placement here.

Moved (but hesitantly...I think this *may* be Physoconops)
Moved from Physocephala.

Robert...I think this is P. marginata
Among other things, the hyaline discal cell and the red scutellum point to that ID...that is, assuming this is indeed Physocephala. The long "3rd antennal segment" makes me wonder whether it may Physoconops.

Probably -
something in Conopidae - maybe Physocephala sp?

See, for example:

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