In some species it is the females which give off an odor, and in either case the distances over which these odors extend and are detected by the males or females respectively are analogous to the inconceivable reach of wireless telegraphy. And who knows but the mechanism of these creatures is set to respond to the swiftly traveling ions which make wireless telegraphy possible? [Illustration] A BABY OF THE SKIPPER BUTTERFLY (_Eudamus tityrus_, Fab.) There is something fascinatingly strange to me in the babies of the winged butterflies, and I wonder why so many people have an aversion for them? Can there be an instinctive fear of anything that crawls, or is not this fear taught us by unthinking persons? The child is not afraid of the wide-mouthed naked little birds in the nest, or the little blind pink mice, and certainly they are no more innocent looking than the brilliant colored larva of the butterflies or moths. What helpless things these babies are! They cannot fly, they cannot fight, they can barely see, and even their gait is a hobbled one. Their business is to eat, and their jaws must keep busy pretty constantly to fill their stomachs with leaf fragments, for the greater part of the soft, flabby bodies is stomach. They are males and females but which they are you cannot tell until they turn into butterflies. Along this creature's sides, like portholes in an ocean liner, are the breathing pores, nine in number. Most animals which live on land take air in through a single opening into a great cavity through which the blood circulates and is purified, but the caterpillars, and all insects in fact, instead of circulating their blood in and out of a pair of lungs, have, running through their bodies, a labyrinth of air passages, all connected with the outside air by means of breathing pores. This caterpillar's eyes are poor affairs, and unless you look closely you will not find them, for they are merely a few raised spots, like blisters, beneath the skin on either side of its jaws. It has, like the spiders, a spinneret and a reservoir of liquid silk with which, as it outgrows its baby state, it can spin its own arbor of tough silk fibers and hide itself from view while it is changing to a butterfly. If in late summer you will put one of these creatures in a tumbler and watch it for a day or two, you can see it plainly through the glass pouring out the liquid silk in a steady stream, waving its head from side to side. The silk comes from a spinneret which is just behind the jaws and is about the color of thin starch paste. The way it loops back upon itself and flows in curves reminds me most forcibly of the way the pastry cook, with frosting in a paper cornucopia, writes one's name upon a birthday cake. [Illustration] A BUTTERFLY'S MUMMY CASE