Have you ever heard a very fast, buzzing noise while in the desert? You may have just encountered one of the Chihuahuan Desert's sneakiest characters—a robber fly.
In many ways, these flies are normal enough, catching and eating other insects. But what may surprise you is that not every kind of robber fly looks the same. Various species of these amazing creatures look like their prey and easily blend in. Some kinds mimic the damsel flies they eat. Others look just like bees! Imagine bees congregating around beautiful flowers, collecting nectar and pollen—but there is someone else buzzing around, too. Suddenly, a quick snatch, and the imposter quickly makes a meal of an unsuspecting bee while the others never know there's a killer in their midst!
If you encounter a robber fly up close, do not handle—many can
give a painful bite. But keep your ears and eyes open. 
You just might get a surprise, the next time you look at a
damsel fly or a bee!
Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.
Contributor: Kodi R. Jeffery, formerly with the Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio, University of Texas at El Paso.
A Robber Fly that mimics a bee.
References
Borror, D. J., and R. E. White. A Field Guide to the Insects, America North of Mexico. Houghton Mifflin Company, Boston, 404 pp.