Flys
http://usatoday30.usatoday.com/tech/columnist/aprilholloday/2004-02-12-wonderquest_x.htm
"Houseflies cannot fly upside down..." says the Science Museum of Minnesota.
They can, however, land upside down by doing a quick "pitch up", says Michael Dickinson, bioengineering professor at California Institute of Technology. Flying right side up, feet dangling, a fly nears a ceiling. She sticks her front two feet out and grabs on. Then she swings her back four legs up like a trapeze artist and sticks them on the ceiling. She grips the surface, ready for a 6-legged stroll, upside down, of course.
Flies have two short strong wings and a huge middle section packed with wing muscles. Three groups of tiny gyroscopes and sense organs placed at right angles to one another tell a fly his speed, his rate of turn, and whether he's being blow off course.
Dickinson tests flies in the lab with a flyswatter like device. "The flies jump so quickly to evade the swatter that they temporarily lose control and flip head-over-heels." Then they quickly jump back upright as their sophisticated gyros kick in.
Fruit flies can turn 90 degrees in 50-thousands of a second. That's ten times faster than the human eye blinks.
Many flies can hover like a hummingbird, spin about their axis like a bullet, zip through spaces little wider than their wingspan, land on ceilings, and even fly backwards. But they don't fly upside down.
