Our Parks Department has received several calls about Asps in the area, so our arborist wants to clarify what the difference is between an Asp and other caterpillars. The most seen caterpillars in the area are Forest Tent Moth Caterpillars and Whitemarked Tussock Moth Caterpillars. Neither of these are Asps and neither will sting. As with any caterpillar, they can cause a rash if you have sensitive skin. The caterpillar that is an Asp and will sting you is the Southern Flannel Moth Caterpillar, which is less common in our area.