INSECTS INJURIOUS TO VEGETATION. CHAPTER I. INSECTS DEFINED. INTRODUCTION. BRAIN AND NERVES. AIR-PIPES AND BREATHING-HOLES. - HEART AND BLOOD. INSECTS ARE PRODUCED FROM EGGS. METAMORPHOSES, OR TRANSFORMATIONS. EXAMPLES OF COMPLETE TRANSFORMATION. PARTIAL TRANSFORMATION. — LARVA, OR INFANT STATE. — PUPA, OR INTERMEDIATE STATE. ADULT, OR WINGED STATE. HEAD, EYES, ANTENNE, AND MOUTH.-THORAX OR CHEST, WINGS, AND LEGS. - ABDOMEN OR HIND-BODY, PIERCER, AND STING. — NUMBER OF INSECTS COMPARED WITH PLANTS. — CLASSIFICATION; ORDERS; COLEOPTERA; ORTHOPTERA ; HEMIPTERA; NEUROPTERA; LEPIDOPTERA; HYMENOPTERA; DIPTERA; OTHER ORDERS AND GROUPS. REMARKS ON SCIENTIFIC NAMES THE HE benefits which we derive from insects, though neither few in number nor inconsiderable in amount, are, if we except those of the silk-worm, the bee, and the cochineal, not very obvious, and are almost entirely beyond our influence. On the contrary, the injuries that we suffer from them are becoming yearly more apparent, and are more or less within our control. A familiar acquaintance with our insect enemies and friends, in all their forms and disguises, will afford us much help in the discovery and proper application of the remedies for the depredations of the former, and will tend to remove the repugnance wherewith the latter are commonly regarded. Destructive insects have their appointed tasks, and are limited in the performance of them; they are exposed to many accidents through the influence of the elements, and they fall a prey to numerous animals, many of them also of the insect race, which, while they fulfil their own part in the economy of nature, contribute to prevent the undue increase of the noxious tribes. Too often, by an unwise interference with the plan of Providence, we defeat the very measures contrived for our protection. We not only suffer from our own carelessness, but through ignorance fall into many mistakes. Civilization and cultivation, in many cases, have destroyed the balance originally existing between plants and insects, and between the latter and other animals. Deprived of their natural food by the removal of the forest trees and shrubs, and the other indigenous plants that once covered the soil, insects have now no other resource than the cultivated plants that have taken the place of the original vegetation. The destruction of insect-eating animals, whether quadrupeds, birds, or reptiles, has doubtless tended greatly to the increase of insects. Colonization and commerce have, to some extent, introduced foreign insects into countries where they were before unknown. It is to such causes as these that we are to attribute the unwelcome appearance and the undue multiplication of many insects in our cultivated grounds, and even in our store-houses and dwellings. We have no reason to believe that any absolutely new insects are generated or created from time to time. The supposed new species, made known to us first by their unwonted depredations, may have come to us from other parts, or may have been driven by the hand of improvement from their native haunts, where heretofore the race had lived in obscurity, and thus had escaped the notice of man. To understand the relations that insects bear to each other and to other objects, and to learn how best to check the ravages of the noxious tribes, we must make ourselves thoroughly acquainted with the natural history of these animals. This subject is particularly important to all persons who are |