המועדפים של bouncyshamrocks

After seeing these wasps, I read up on them a little. Orussus occidentalis is the only species of Orussus in North America with the abdomen predominantly red according to this research paper, although some species in eastern North America have red at the tip of the abdomen; its nearest relative and the only other species in the genus with a similar extent of red on the abdomen ranges across the Palearctic. Also, wasps in this genus use the antennae and forelegs to echolocate their host species inside the wood! So the use of echolocation may be why they walk in such odd ways--intermittently with many pauses, forward, backward, repeatedly turning around, etc., some of which is visible in the video here (individual on the left), although the video also shows two individuals interacting when they meet.

We came across this mating pair hovering in a "sun-speck" along the creek-adjacent, woodland trail/road though Mitchell Canyon. To the naked eye it wasn't entirely clear what it was, though I thought I could make out a foamy "nuptial gift" (suggesting a balloon-bearing empidid).

However, I didn't realize it was a mating pair until zooming-in on a photo on the camera display. We observed the two in (roughly) "stationary hover" for over two minutes...don't know how long they were hovering before we noticed them.

After posting this, I noticed @kueda made a very similar observation very nearby about 9 years earlier (with nice accompanying info, and a wonderfully sharp image!)...as did @abmdjoe about 3 weeks earlier here. Seems there's a stable population in the area :-).

collected on grass, ID tentative
10.05. pics 1+2 with length ~5 mm
12.05. pics 3-7 with length ~8 mm
13.05. pic 8
17.05. pics 9-11, length 11-12 mm
21.05. pics 12-14 length 20 mm
25.05. pics 15-16 length 24 mm
28.05. pics 17-20 prepupa, last measured length the day before 25 mm