On an Andrena, believe is A crataegi.
Host Lasioglossum sysimbrii
It's a wasp parasite.
INaturalist gues is in the genus Xenos and it's Xenos vesparum.
One of the two Andrena milwaukeensis seen today was parasitized.
Andrena with internal abdomenal endoparasite (Stylopidae)?, Albany Pine Bush Preserve, Albany County, NY, April 2024
Same bee as https://www.inaturalist.org/observations/216024143. I didn't notice anything odd about the bee until processing the photos. The "dent" in the tergite is visible in some of the photos. This is the only photo that clearly shows the gap between the terga, allowing a peek at something inside.
My first time seeing a stylopized bee, on a Andrena milwaukeensis, bee sighting entered here: https://www.inaturalist.ca/observations/215499889
Duplicated from https://www.inaturalist.org/observations/130024606 for this parasite observation
Wasp observation:
https://www.inaturalist.org/observations/214587473