Measuring the earth, one millimetre at a time

Here's another of my midnight visitors. I've never seen an inchworm this tiny before. It was hurrying across my nightstand, a mere thread stretching out, then folding itself in half. I moved a box aside, and it leapt onto my finger. As thin as a sewing thread. Racing across my palm. It's about 4 mm. long. And here it is, folded. The inchworms are the larvae of the Geometrid moths; they get their…