The adults of these species are large longhorned beetle, dark brown to almost black. Both species possess three tooth-like projections on each side of the pronotum. There are 15-20 antennal segments in this species. They have a heavy-bodied, cylindrical appearance. Their bodies are white to pale yellow.
Heads are small and brown.
Legs are so small that they may be overlooked. Most information regarding biology results from research on borers on pecan in Georgia. Tilehorned prionus infests roots, larvae feeding on roots for 3-5 years before pupating. Broadnecked prionus has been reported damaging apple roots in Rhode Island. Its range is eastern U.S., into Oklahoma.