Several of these wasps were entering and exiting holes drilled in a tree stump cut flush with the ground. Noted were their yellow antennae bases and white facial marks. Also present were several tachinid flies that were paying close attention to the holes. There was fresh sawdust in the vicinity of the holes: did these wasps dig their own holes, or was it carpenter ants?

Also noted was a similar wasp with a yellow face and brown antenna bases (separate submission HERE).