I lived in New England for most of my life and I have never seen a waterbug that looks like this:
Click to embiggen, and not sure if link will work, but original photo here. If it doesn't, it's from Brian Marchese, the hardest working drummer in the Happy Valley and a dear Baystate friend from my past.
Anyway, if you can't get to the link and read the comments, the bug is about four inches long. It was trying to gain access to the Montague Bookmill. A place where I spent many happy hours of my squandered youth.
Somebody picked it up. That would not have been me.