Male, the 13 antennal segments clearly visible. Antenna segment 3 as large as 4 and 5. Note the position of the antennae and the pseudopupils.
Can't find ID key for Sphecidae, so I trust iNat suggestion only for thi genus...
I have other picture if some precise details needed to ID...
Sighting and photos (c) mmh_m.
Field Notes - Watched this little wasp moving get in and out of a burrow then block it up with what looked like tiny pebbles.