This pretty blue and brown caterpillar is often found in large numbers in oak forests. They can be a pest, but not on the level of the dreaded gypsy moth, which can defoliate an entire forest in a matter of weeks. They get the name "tent caterpillar" because the group of insects they belong to tend to make silk webs or mats on the branches and trunks of the host trees. They eat a variety of trees, especially wild cherry -- the cyanide in the cherry leaves may be the reason that this caterpillar can spit "tobacco juice" that contains a small amount of cyanide.

The very similar Eastern Tent Caterpillar has a solid white line down the back, instead of spots. Its habits and food plants are similar.

The moth that this caterpillar turns into is a pretty fawn brown color with subtle stripes and a furry body.