Sliding linear bearings-Trees bearing unwanted gifts

        It's been 20 years since the squirrel first leapt out of the Christmas tree at Clark W. Griswold (Chevy Chase) in National Lampoon's Christmas Motion bearing  Vacation, triggering panic in the extended family that had gathered for the big, old-fashioned family holiday.

        Since that time, off the big Support Rail Units screen and out in the real world, hundreds of thousands of other wild things have found themselves transplanted into the homes of Americans, catching rides on Sliding linear bearings hundreds of thousands of versions of "the Griswold family Christmas tree."

        Insects are the most frequent Christmas tree-transported visitors to our holiday households, and the egg cases of praying mantises seem to be the most frequently reported. The female mantids cement their Styrofoam-resembling, tan to gray-brown egg cases to plant stems and twigs, including the branches of Christmas trees, in early fall.