The prionus belongs to a beetle family known, appropriately enough, as longhorns.
Most sport antennae as long, or longer, than their bodies.
The antennae of insects are extraordinary sense organs combining the capacities for touch and smell. The prionus male, whose antennae are larger than the female's, packs them with sensory pits and chemical receptors that, among other things, help him find a mate. Prionus beetles grow up to 2 inches long and prefer mountainous areas with plenty of oaks, cottonwoods and other trees, into the roots of which their larvae bore, often causing damage. They sometimes wander into homes, attracted by lights, and crash into windows. Taking wing at dusk, they are known to startle high-country campers.