How does a house fly land and fly upside down; i.e. on a ceiling?

Prior to the availiblity of high-speed photography, scientists
believed houseflies performed a fighter pilot style "barrel roll" when
landing on the ceiling.  However, modernized technology allowed
investigators to see what is really happening.  It turns out that the
fly's movement is more akin to a circus acrobat than an airplane
stunt.  The fly, positioned very close to the ceiling, kicks up its
front legs over its head and gains hold of the ceiling; once this
foothold has been secured, the fly performs a somersault of sorts and
gains a hold with its rear legs as well.  The fly is able to grasp the
ceiling because of sticky pads found under the claws of its feet.


Links:

Indiana University Bloomington—A Moment of Science
http://amos.indiana.edu/library/scripts/fly.html

CoolQuiz Trivia
http://www.coolquiz.com/trivia/explain/docs/flies.asp 

Scientific American: Fly Like a Fly
http://www.sciam.com/article.cfm?articleID=000DF125-5545-1C75-9B81809EC588EF21


Search Strategy:

housefly land "upside down"
fly land "upside down"


Xargon-ga

Thank you very much!  You helped my husband astonish his friends.

Not relative to your question but perhaps interesting. I once had a
big blowfly flying around my bed at night that was loud and would not
allow me to sleep at all. I got up,opened the door and  swatted paper
and stuff till he/she flew out, after which I closed the door. Nearly
asleep  a few minutes later another loud blow fly was heard flying
around my bed.  Again I got up and repeated procedure.
 Five minutes goes by and  yet another loud blowfly buzzing around my
head. This time I began to think that something was amiss and perhaps
there was some way same fly was getting into bedroom although no
windows open and door was locked with no other openings in room at
all. I chased fly out of room and left light on and waited a bit. 
Only one minute later same fly was back in bedroom having had the
intelligence on each occasion, even though pitch black, to fly down to
bottom of door external to my bedroom, i.e the hallway, and crawl back
through the very narrow space between bottom of door and floor.
I would have thought that would have taken some intelligent thought
processes which I would have assumed was beyond a fly, but apparently
not!!!