In the very early hours of the morning, in a Harvard robotics laboratory last summer, an insect took flight. Half the size of a paperclip, weighing less than a tenth of a gram, it leaped a few inches, hovered for a moment on fragile, flapping wings, and then sped along a preset route through the air. This demonstration of the first controlled flight of an insect-sized robot is the culmination of more than a decade's work.