Subject: Big Fly, Wasp, or other?
Geographic location of the bug: Truckee, CA
Time: 05:54 PM EDT
Your letter to the bugman: I had this large flying insect land on my porch and it appeared to be eating a flying ant. The unknown insect almost looked like a large, elongated horse fly but it might have had a stinger. It had brightly colored orange/red legs
How you want your letter signed: Ross
We enjoyed researching your query, but we are only confident with our identification of your Robber Fly to the family level, though we are gambling that we have also correctly identified the genus. We believe this is a Giant Robber Fly in the genus Promachus and it looks very similar to this unidentified individual posted to BugGuide as well as this unidentified individual in our own archives, both unidentified individuals having been sighted in California. California Robbers identifies four species of Promachus from California, however none of those have red legs. We suspect this might be either an undescribed species or possibly a species not previously identified in California. The prey is a reproductive Termite alate, probably the Western Drywood Termite which is pictured on the UC Master Gardeners website. Perhaps one of our readers will be able to provide a more conclusive identification.
Thank you for the information! I found this all quite interesting!