Common Mormon Caterpillar

The caterpillar will spend most of its time eating, and has powerful jaws that will serve this purpose. These well-developed jaws (mandibles) have very sharp cutting surfaces that easily chop leaves. The mandibles bite off plant material and tear it into small, easily digestible pieces. Underneath the mandible are the two maxillae, smaller mouth parts that guide the food into the mouth. The caterpillar holds onto the food with its thoracic legs.

The maxillae also have taste cells; these chemical detectors tell the caterpillar to eat when the food is appropriate, and not to eat when the food is not appropriate. The tiny antennae, which are near the mouth parts, sense smells.

also you can see the ocelli of this fellow ( Simple eyes)