UC Cooperative Extension Ventura County
669 County Square Dr. Suite 100
Ventura CA 93003
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California Prionus Beetle
The California Prionus beetle, Prionus californicus, can be as large as two to two-and-a-half inches. It is uniform dark, reddish brown and has antennae that are about half as long as its body. The adult is attracted to light at night and sounds like a small airplane approaching. The larvae develop in dead and decaying logs, stumps and roots, and the adults emerge during the summer months. Almost any dead wood will serve as a breeding site. Both larvae and adults are harmless. The adult might pinch you with its mouth parts if you pick it up wrong. Also, if you don’t mind, the insect is very acceptable cat food.