The entry hole made by the polyphagous shot hole borer (Euwallacea sp.) is about the size of the tip of a ball-point pen. (Photo credit: Monica Dimson, University of California Cooperative Extension) Leave a Reply Cancel reply Search Search for... Search Get New Posts in your Inbox! Enter your email address to subscribe to Entomology Today. You'll receive notifications of new posts by email. Email Address Get Certified!