(6) Bugs have their mouth parts prolonged into a sharp beak with which they puncture the skin or bark, instead of chewing the leaves, as do beetles. Flies, gnats, and other similar insects do not usually injure vegetation so much as do some other classes of insects, the principal damage being done to fruits; but they have been found to be the cause of some of the most serious diseases in both man and the lower animals. The Department of Agriculture divides the injuries done by insects into classes according to the products injured, and in the list they place first the injury done to cereal crops. The insects which damage the corn crop most seriously are the corn-root worm, which feeds on the roots of young corn, causing it to fall over and die, and which sometimes takes the whole corn crop of a large region. The next most important is the boll-worm or ear-worm. Most persons have seen this worm in the ears of sweet corn; ninety ears out of every hundred contain a worm which destroys from one-tenth to one-half the corn. Some years every ear in large regions is infested. In the South the field corn is attacked as badly as the sweet corn, but in the great corn states the injury is much less. Even here, however, the total loss is very great. Almost equally important is the damage wrought by the chinch-bug, which is also one of the greatest pests in wheat and oats. Every year in different sections of the country, bill-bugs, wire-worms, cutworms, cornstalk borers, locusts, grasshoppers, corn plant-lice and other insects, destroy millions of bushels of corn. Of the cereal crops, wheat suffers most from insects. Of the large number of insects that attack wheat, the three important species are the Hessian fly, the chinch-bug and the grain plant-louse or green-bug. The Hessian fly has been known to destroy as much as sixty per cent. of all the wheat acreage of a state. Fortunately, this damage is done early in the year, so that when whole fields are destroyed they can be replanted with other crops and only the cost of seed and labor is to be counted as a loss. But more often the field is only partly destroyed by the fly; it is not necessary to replant, but the yield is small, often not more than one-third. Some years the loss from the Hessian fly is very heavy, at other times comparatively light, yet there are few years when the loss is less than ten per cent. of the total crop from this insect alone,--which meant last year a loss of 72,500,000 bushels. The chinch-bug is responsible for the loss of five per cent., or one bushel out of every twenty. It attacks the straw, causing the heads of wheat to fall over and wither away. The injury done by the green-bug comes just as the wheat begins to ripen, the tiny green creatures attaching themselves in great numbers to the heads of the wheat. Other insects which prey on the wheat crop are grasshoppers, the wheat midge, cutworms and army-worms.