Plesiomma unicolor is a robber found only in Texas and New Mexico in the US. And it is the only species in the genus that crosses the border from the south. There are apparently 20 described species from Central and South America and quite a few more undescribed species. Several species occur in Mexico and the West Indies. And Eric Fisher says this is the main Stenopogoninae type found in the Caribbean.

All the shots here, including this one, are from Mills County Texas where Terry and Janice Fischer found them in their yard in June 2013. I thought there was something wrong with the mouthparts when they first sent this shot. But it is a fairly large Stenopogoninae member with a small proboscis sheath. Male on the bottom here. There are virtually no photos of this species anywhere. And Eric Fisher has seen some Central American members of the genus but not this one.



And a male from the rear angle. Elongate body and impressive dark wings. Here are Terry's observations on the photo day:

"It was dead calm, overcast, and spitting rain early this am.  Generally I wouldn't have gone out in those conditions.  Almost immediately I spotted two flying together and acting amorous.  The combination of vitex and cholla cactus created a pretty dense canopy with lower plants and weeds which were in shade.  Both flies were flying low, plus or minus a foot above ground, and slow under the canopy, their wings made no buzz, even when accelerating.  Luckily they kept coming back to a couple favorite perches.  They weren't very wary, I had to work my way thru the canopy, still have cholla needles stuck in various places!  I would guess that they can handle only small, delicate prey that would be on blades of grass??? "




A facial portrait showing the converging face with widening lower which is characteristic in this group. Note the small proboscis sheath. Unicolor seems an appropriate color description as well. Eric Fisher's Asilidae of Central America says: "Plesiomma have petiolate abdomens, wasp-like coloration, and rather slow, deliberate flight. These flies are usually seen at the edges of forest, or inside of relatively open, shaded forest." He states they hunt by hovering deliberate flight and they often perch on horizontal stems.



And one of the most impressive robber-takes-robber combos I have ever seen now. Terry and Janice have a local group of Saropogon dispar (see page here) and this one has taken a prize Plesiomma. You can compare size here. And what a fine shot Terry. He covered his path over and over looking for the recurrence of the Plesiomma. Likely the only live shot presently of this genus on the internet.



Another pair shot from the Fischer yard in 2014 this time. Still elongate and red. Apparently always possible prey for the local Saropogon dominators as well.