The Xerces Society’s Pollinator Conservation Resource Center is now on-line!
It has a clickable map of North America; you can find all sorts of resources indexed there. For example, there is a Guide to Upper Midwest plants for Native Bees! Enjoy the downloading.
I could not resist this photo of an adorable little bee, even if it isn’t a North American bee; the colors were so lovely! Thanks to AussieGal for sharing!