Black non-biting insect
Every spring these black (not a beetle) are on my blades of grass, dock, deck. They do not bite, have wings and are slow moving. I think they are the insects that lay eggs on my pontoons and dock pipes. The seagulls love them. Top of the mitt in michigan
Presque Isle County Michigan
That description could fit a lot of different sorts of insects. Without a photo to work from, I can only guess that they might be adult stoneflies. See the information at https://en.wikipedia.org/wiki/Plecoptera. Unfortunately, there are few pictures of the adults at this site. I have seen many in the 3/8 to 1/2 range that are black or very darkly colored.