Housewives may be surprised to learn that a cockroach can live five years, and that it takes a year to develop to maturity from the egg. The female lays her eggs in a horny capsule, like a spectacle case, which she carries about with her until she is ready to deposit it in some suitable place. Later she returns to help her cockroach babies out of their shells. Like the cricket, cockroaches love the night and shun the daylight. They cannot tolerate cold weather, and though there are 5,000 species they mostly inhabit the tropics, where they are the plague of domestic and ship life. It is said that "ships come into San Francisco from their long half-year voyages around the Horn with the sailors wearing gloves on their hands when asleep in their bunks in a desperate effort to save their fingernails from being gnawed off by the hordes of roaches which infest the whole ship." (Kellogg.) And now a rumor comes to us that the cockroach carries cancer. [Illustration] A DEMON FLY KILLER: THE PRAYING MANTIS (_Paratenodera sinensis_, Sauss.) Its spiny fore legs are built to hold the struggling flies, while, with its sharp jaws, it tears them to pieces much as a hawk or eagle holds its prey with its talons and tears it to shreds with its beak. It is wasteful, too, of its food, as wasteful as the sea lion, or the seal, throwing away the half-consumed carcass before it is finished and pursuing another victim. So voracious is its appetite and so successful is it as a hunter that Doctor Slingerland of Cornell has introduced the eggs of a species of this mantis from Europe and distributed them among his friends in the Northern states as a beneficial insect. To kill a praying mantis has been in Mohammedan countries almost as great a crime as it is to kill an albatross at sea, but this was not because it kills the swarms of flies so common in those lands, but rather because of the prayerful attitude made necessary by its fiercely spined and powerful front legs. Its head is so loosely set on its long neck, or thorax, that it can move it from side to side with the greatest ease. Fabre declares that "the mantis is alone among all the insects in directing its attention to inanimate things. It inspects, it examines, it has almost a physiognomy." Perhaps one is warranted in having a feeling of repugnance toward the mantis, for no other living creature has more horrible habits. There has always been something horrible about the cannibalism of human beings who ate their enemies killed in battle, but this has never seemed so revolting as the practice of the Fijians who killed members of their own tribe in cold blood for purposes of the cannibal feast. The female mantis goes a step farther than this, for she begins eating her lover even before the courtship is over.