Bug of the Month August 2010: Red Footed Cannibalfly

Ed. Note:
August 4, 2010
We apologize for losing track of time, and posting this Bug of the Month a few days late.  There has been a flurry of submissions of Red Footed Cannibalflies in the past week, so it is a very appropriate selection.

Weird, Beautiful Dragonfly/Hornet
Location:  Northern Kentucky, near Cincinnati, OH
August 1, 2010 1:46 pm
Dear Bugman,
I saw this über-fascinating alien bug yesterday, 7/31/10, in my yard. I’ve never seen anything even remotely like it. It was close to 3 inches long. Its head and thorax look like a dragonfly in shape. It has 2 matte black eyes, practically no antennae, and its head, thorax, and legs are fuzzy. It has a pair of very pale brown, nearly transparent wings that lay flat down its back like those of a wood cockroach.

Its pale yellow and black striped tail is long, segmented, and straight, starting thick at the thorax and ending in a long black tip which I sincerely hope is an ovipositor. It looks like it has lost a portion of one of its front legs. Otherwise, it’s a beautiful specimen. I have many fabulous pics of it. I even caught it in flight! Can you help identify this weird beauty?
Ragdoll

Dear Ragdoll,
You have taken excellent documentary photographs of a Giant Robber Fly in the genus Promachus. These Giant Robber Flies are also called Bee Killers because they prey upon bees and wasps that they are able to catch in flight.  According to our Audubon Society Field Guide to North American Insects and Spiders:  “The Bee Killer often rests on leaves and branches with a clear view of flowers visited by Honey Bees.  It seizes its victim from above, pierces its body and sucks out juices, then drops the emptied prey.  A dozen or more bodies may pile up on the ground below a favorite perch.”  Based on the red legs and dark tibiae, we believe your specimen is the Red Footed Cannibalfly or Bee Panther, Promachus rufipes, and you may compare your images to those posted to BugGuide.  We also agree that that is an ovipositor, which makes her a female.  You can compare your image to this photo on BugGuide.  It is worth noting that generally, the name of an insect that is a compound word ending with “fly” is not a true fly, like a dragonfly or butterfly, and when the common name is formed of two words like Robber Fly or Crane Fly, the insect is a true fly.  The Red Footed Cannibalfly is an exception, since the compound word is used for a true fly.

Dear Daniel,
Thank you so much for the wonderful info. That is indeed my bug! Yesterday, I  heard a loud, fast buzzing and spied another, much smaller one. I immediately assumed that it was a male. Oddly, the female made almost no sound when in flight.
I’m guessing that the Robber Fly probably doesn’t hang out much in the ‘city’. Perhaps this pair is just another casualty of a shrinking habitat. 🙁  . I have large, lush flower beds that teem with bees, albeit only the rare ‘honeybee’.  The female was perched on the fence railing overlooking the beds below, just like in your description.
Even though she doesn’t sound like a particulary ‘nice’ lady, I feel privileged that she’s come to pay a visit to my little patch of nature in the city. 🙂
Thanks again for your prompt reply and fascinating insight. You all really go above and beyond. I suspect it is a true labor of love.
Regards,
Ragdoll

Dear Ragdoll,
Thanks for getting back to us.  Now it is our turn to thank you.  Your letter with its gorgeous photos prompted us to do the species search.  Because of your posted letter, a second letter arrived today from Indiana.  The person who wrote was able to properly identify the Red Footed Cannibalfly in question based on your excellent images.  We were also prompted to check on a letter submitted on July 28 from Tennessee, and that time we only identified the Red Footed Cannibalfly to the genus level of Promachus.  Because of your letter, we were able to take the identification to the species level Promachus rufipes.

Update
August , 2010
Wow! You guys made my day! I’m always taking pictures of everything nature, and it is so nice to find a place to share those images. I’m really enjoying your site and it gladdens my heart that there are people like you out there that truly believe in co-existing with nature and encourage knowledge and tolerance.
I’ve already learned so much, but I admit that I had to stop reading the ‘unecessary carnage’ section because it’s so heartbreaking. That horrible woman who killed all those beautiful moths! 🙁
I’m going to submit more images to you, in hopes that ou may find them interesting. You may well have created a monster….

We look forward to receiving any additional photographs you send to us, but since we have such a small staff, we are unable to post but a fraction of the mail we receive.  Please do not give up should your emails go unanswered.
Baron von BugMan, the creator of monsters