I saw this bug in a backyard in northern mn it is bigger then a lady bug, but is the same shape. It is metallic silver with black spots.
You found a common willow Calligrapha.
This insect is found in most of North America. And as the name suggests it feeds on willows.
There are several species of beetles in the genus Calligrapha that look similar, but the markings are distinct for this species. There are some variations in coloring
Cool looking beetle!