Two milkweed beetles were apparently mating on the milkweed.
A Milkweed Beetle of some sort. Banded antennae, femurs are red, bases of antennae are black, elytra are fairly hairy, so similar to but a bit different from T. femoratus.
Doesn't seem to look like T. tetrophthalmus, as it is missing the larger elytra dots, but maybe that's not diagnostic.
Found smushed on my car, so likely got picked up while travelling.