The eggs of locusts are usually laid in the ground. With the Rocky Mountain specie- from twenty to thirty-five are laid together in a com pact mass covered with a pod. The locust itself occupies seven weeks from the time of hatching in attaining its full growth. The locusts of the Old World have been known to fly to Central Europe from their permanent breeding-grounds in Central Asia. In North America they often extend their flights over a distance of from one thousand to two thousand miles, or from 1:11on tana to Missouri, and even to Texas. Flight takes place during the day and ends toward sundown. The rate of travel varies from three to twenty miles an hour, depending upon the wind. The height at which the migrating swarms move differs greatly, according to the direction and height of the air-currents. They have been noticed, for example, flying far above the summit of Parry's Peak, an elevation of more than thirteen thousand feet.
The best measures advised for their destruction are harrowing and late fall plowing for the de struction of the eggs, crushing of the newly batched individuals between rolh.rs, and the collecting of the young individuals by an ap paratus consisting primarily of a coal-oil pan either dragged along the ground or mounted upon wheels. Of late years a good remedy has been discovered in the use of a mash of bran and arsenic, which is distributed in little moist masses about the infested fields. The locusts are
fond of tins mixture, and it is fatal to them. Good results have been reached in South Africa, and to a much lesser degree in the United States, during the past few years, by distributing a pathogenic fungus of the genus Sporntriehum, which kills the locusts when they occur in swarms. Locusts are also subject to several other diseases; there is a fungus of the genus Mueor which undoubtedly kills them. and another (Empusa grylli) frequently destroys them in great numbers. They have many natural enemies among birds and parasitic insects, including hair worms (see lImawortm), and insects that devour their eggs. Locusts are eaten in many countries, roasted or fried in butter. They are also pre served in brine or dried in the sun. They thus appear in the markets of Arabia. Syria. Egypt, and .:11adagasear, and are even exported as an article of commerce. They are also candied and eaten as a delicacy in China, and in the Philip pines they frequently form an important article of diet among the poorer classes.
Consult the First, Second, and Third Reports of the United States Entomological Commission (Washington. 1877, 1879 and 1882) : also Munro, The Locust Plague and Its Suppression ( London, 1900).