These are but a few typical direct losses. To them must be added the cost of fighting destructive insects. To spray apple trees for the codling moth alone $4,000,000 is spent an nually, to combat the San Jose scale $10,000,000. The New England States and the national gov ernment have already expended $7,000,000 to check the ravages of the brown tail and the gypsy moth and are spending $1,000,000 an nually in this warfare. And so on almost ad iafinitum; for every important crop has its insect enemies. Nearly 300 prey on the apple, on clover and grape each 100, on sugar beet 70, on cherry and plum each 50, to mention only a few instances.
Another important group of destructive in sects includes those species that attack domes tic animals, scarcely one of which but has its parasites. Some of these insects feed more or less indiscriminately upon several species of animals; others are specific to one species or a few closely related ones. Often horses, cattle and sheep are so seriously parasitized that they die, to say being weakened when less seriously at d. The stomach and in testines of the horse are frequently so in fested with botfly larva that it is a wonder the animal lives, much less works. The hides of cattle are often ruined because cattle botfly larva feed beneath the skin on the animals' backs. When the nasal passages and other head parts of sheep become densely populated by another species of the animals often go insane and die. In addition to these are horn flies, gadflies, screw worm flies, lice, fleas and many other domestic animal pests, some of which may not directly cause death but all of which reduce vitality, thus wasting energy and food necessary to keep the animals in good con dition. At the same time these pests may carry the germs of disease.
All this damage wrought by insects to culti vated crops and to domestic animals implies inestimable money losses. But to it must be added the also inestimable injuries to manu •factured products. Naturally the first thought concerns the injuries to foods; these un doubtedly suffer most for nothing is safe unless stored in receptacles through which insects can not burrow or thrust their eggs. But many other articles manufactured from organic ma terials are destroyed by insects. Certain species of insects attack wood whether used in the construction of buildings, furniture or imple ments. In some tropical countries termites or white ants, working always beneath the sur face, devour wood until collapse occurs, thus furniture and even houses that become infested with them soon cease to be safe for human uses. In short everything of organic origin has its enemies; even boo.s and drugs do not escape.
There are yet other important roles which insects play— those in which they attack man directly or infect him with disease, the germs of which they carry upon or in their bodies. Because of commercial intercourse scarcely any habitable region of the globe is free from such insects as house flies, fleas, mosquitoes, bedbugs and others equally or more annoying and dan gerous. Some of these species attack by
means of jaws (fleas), by beaks (lice and bed bugs), by ovipositors (wasps, bees and the stinging species of ants), in most of which cases a poison is injected into the wounds though in others the mere bite or puncture is enough to produce irritation of the injured part. In other cases the insects are pro vided with hairs which produce a nettling or urticating effect as in the case of many caterpillars, notably those of the brown tailed moth. Again, some beetles when crushed blister the skin, for instance °Spanish fly,* or cantha rides used in medicine. Bees and wasps though capable of inflicting considerable pain, and, in extreme cases of highly nervous persons, even death, rarely attack human beings unless in defense of themselves or of their homes. In such cases the immediate application of an alkali such as ammonia is the best remedy.
Important as the direct attacks of insects upbn man are, they are however less serious in their effects than the indirect ones; for insects which prey upon man or as in the case of the house fly, often play more important indirect roles than on account of their mere bites or stings or contact with the human skin or with food Certain species of Oriental mosquitoes carry such maladies as the filaria diseases of the East (chyluria, elephantiasis and lymph scrotum); others impart malaria, yellow and dengue fevers. House flies in Egypt and the Fiji Island carry purulent conjunctivitis; in other parts of the world they also spread typhoid fever and Asiatic cholera; tiny hippe late flies disseminate ((pink eye" in the southern United States; fleas are said to spread bubonic plague; tabanid and stomoxyd flies are charged with disseminating anthrax by means of specific bacilli just as cucumber beetles spread the wilt or blight of, cucumbers and canteloupes and as bees and other nectar feeding insects spread the fire blight of pears, apples and quinces. From these few examples, therefore, the importance of insects to man assumes a very threatening aspect. Taking this list as a whole the house is probably the worst offender simply through its world-wide distribution. Because of its filthy habits (the larva being developed in manure, the adults carrying this matter upon their bodies), and because it not only soils the surfaces upon which it alights but pollutes the human food upon which it feeds in the adult state, it is fought by cleanly housewives the world over. The cost of keeping it out of American homes is estimated by Herrick to be $10,000,000 annually. To this figure must be added the cost of fly traps, poisons and other methods of control. Similarly the cost of control of such filth carrying insects as roaches, and of, such parasites on human beings as bed bugs, fleas and lice doubtless equals this enor mous figure.