Fig. 117.—Praying Mantis, or devil’s horse.
Fig. 118.—Cricket.
Fig. 119.—Mole Cricket.
Fig. 120.—Front Leg of Mole Cricket. × 3.
Economic Importance of Grasshoppers.—Great injury is often done to vegetation by grasshoppers; however, the millions of tiny but ravenous eaters hatched in early spring are usually soon thinned out by the birds. The migratory locusts constitute a plague when they appear, and they have done so since ancient times. The Rocky Mountain locusts flying eastward have darkened the sky, and where they settled to the earth ate almost every green thing. In 1874–5 they produced almost a famine in Kansas, Nebraska, and other Western states. The young hatched away from the mountains were not healthy, and died prematurely, and their devastations came to an end. Of course the migrations may occur again. Packard calculates that the farmers of the West lost $200,000,000 because of grasshopper ravages in 1874–5.
The cockroaches (Fig. [116]), kindred of the grasshoppers, are household pests that have migrated almost everywhere that ships go. The praying mantis (Fig. [117]), or devil’s horse, also belongs to this order. It is beneficial, since it destroys noxious insects. Which of its legs are specialized? The walking stick (Fig. [121]) and the cricket (Fig. [118]), like most members of the order, are vegetarian.
