Sally Ottaway, age 9, of Wichita, Kansas, or her question:

How does the click beetle click?

Some 500 different click bettles make their homes in North America. Most of them are modest brownish grey fellows, but they have some very gaudy relatives living in tropical regions. All the click bettles are acrobats. If one of them falls on his back, which he often does, he rests a minute to get set. Then over he goes in a somersault and lands right side up with a loud click.

The armor plating on the click beetles underside is divided at the waist line. Right in the center of this seam is a little notch. A prong from the lower side fits into a groove in the chest side. Normally this seam fits snugly tog"ther. But the click beetle can open and close this crack in his armor to suit himself.

He does this when he finds himself lying on his back. The seam opens to allow him to arch his back. He presses on the ground with the back of his head and wings to get purchase, then suddenly lets go. The sudden jerk sends him up and over i a loop to land on his fee'The click is made when the little prong sudder._y snaps back into the groove to close the seam in the armor.