Gerda Dezeeuw, age 10, of St. Catharines, Ont., Canada, for her

question:

Why do flies rub their feet together?

A busy fly zooms from here to there, landing on all kinds of surfaces. Her tin feet are covered with tinier hairs, and these furry little boots get mussed and dirty. From time to time she stops to clean them. She rubs them together to scrape and brush off the dust and dirt, very much as you wash your soapy hands together.

Let's not imagine, however, that the fly is to be trusted as a clean little creature. She may scrub her dirty feet, but when she lands on our food and such she is sure to leave behind some of the dirty specks that she missed. And some of these specks may be germs.