I wanted to let you know how much I appreciate your website. I have come to your site at various times this past summer to find out what creature was lurking in my backyard. My first visit was to find out what a Wheel Bug was and lastly I found information on the Bearded Robber Fly and a Hanging Thief. Thanks again for all the valuable information you provide. I have included photos of my latest inquiry ! Regards,
What an amazing documentation of a Robber Fly in the genus Promachus feeding on a related Hanging Thief. We found a website with great photos that identifies your species as Promachus vertebratus.