"Peter Shull" wrote in message
news:GKvVd.71631$wc.34639@trnddc07...
Prolly both?

http://www.usatoday.com/tech/columni...derquest_x.htm

Houseflies are messy eaters.
Jim Kalisch, Department of Entomology, University of Nebraska-Lincoln

Q: What are the little black dots that flies leave behind all over the
surfaces in my house? (Alison, Lissewege, Belgium)

A: Flies have a disgusting way of feeding. They can't eat solid food since
their spongy mouthparts are too soft to break up food. So, they soften the
victual by spitting on it. The saliva melts the piece of food. They sop it
up like a sponge into their digestive tract. Since the food is already
liquefied, flies digest nutrients fast and soon expel fecal material.

You can see this on a revoltingly grand scale in the movie "The Fly" - not
the original, but the remake starring Jeff Goldblum. He sits down in front
of a box of donuts, hurls all over it, then slurps up the resulting mess.
The look on Geena Davis' face as she observes this scene is priceless.

B.