Saw this tiny one on some kind of grass/ plant ~2' out in a pond. Very difficult to photograph due to the size and position. But she stayed there, which helped. It even looked like she was ovipositing (photos 8-9). Couldn't quite get definitive photos, though.
One of iNat's suggestions is Tetramesa, which would fit the behavior. But I can't be confident to ID at that level.
Seen on Aesculus glabra (207707560).
About 2-3mm long.
For the images taken with flash, iNat is pretty sure Chalcidoidea. For those without, Entedoninae.
I chose to stay at the higher taxon. I only felt certain that it was a parasitic wasp :D
It was very cooperative, staying put as I manipulated the leaf to try to get pics. Once I concluded that I would have to use flash, it only went along with that for a few shots and then was gone.
I included some of the non-flash photos because they show the sculpting of the thorax (photo3) and the shape of the face (photo 4).
Very small. Seems to have emerged from a Phytomyza phyllireae pupa mining Phyllirea angustifolia
https://www.inaturalist.org/observations/205124062
~1 mm body. Ovipositing into a parasitized aphid on an Erigeron canadensis leaf.
~3 mm body. On a cloudy 90 degree F day. Maybe Colotrechnus based on white wing venation. Needs expert review.
DHH-22-367