Like M. americanum, the caterpillars stay together until nearly full grown. The moths are typically light grayish brown or tan with two brown lines on the front wings instead of the white ones ...
We have recently had an outbreak of Tent Caterpillars in the area. Driving down the road, it appears that many of the brush trees growing along rural roadways contained the caterpillar tents.
Those Webs in the Trees By Carl Hoffman, University of Minnesota Extension No, they are not “army worms”.  Those conspicuous white masses of webby material that are seen in the forks of branches ...