Chalybion californicum- Mud Dauber Wasp
I was photographing some butterflies in my garden when this metallic blue wasp landed near me and startled me. The blue green color of this bug is striking and I'd never seen one like it in Chicago before. After some Googling I've learned that it is a Chalybion californicum or commonly called a Mud Dauber Wasp.
In all of the pages that talk about this particular wasp I couldn't find any information on whether it was beneficial in the garden or even a pollinator but I can't image it does any damage to plants. The one benefit I have been able to find on it is that it stocks the nest with black widow spiders after it lay eggs.
source: mud daubers