Airy mannered, filmy winged, and long antennaed, one would hardly suspect the gentle creature perched on the lily as being the mother of the insectean inventor of the first submarine. She drops her eggs on the river bottom. These hatch, and the little wigglers build themselves cases of fiber and pebbles, which they line with silk. In these they can rise and sink at will. The diving beetle preys upon them as shown.