CHAPTER XI.

INSECTS AND THEIR REMEDIES.

e working farmer is so occupied in the pursuit of his profession, and by the study of the phenomena by which he is surrounded, upon a correct appreciation of which his success will largely depend, that he rarely has sufficient time to devote to botany or entomology as a science. The laws of vegetable growth, an intimate knowledge of useful and noxious plants, and, above all, a clear perception of, and discrimination between his friends and foes in the insect world, are among his urgent needs. Next to the contingencies of season, his prosperity will depend upon the extent of insect depredations. Millions of dol

lars' worth of property are annually destroyed by insects, and a knowledge of their habits is required, that we may learn how to deal with them, in order to stay their ravages. If farmers more cor:ectly appreciated the aggregate losses by insects, they would probably take a deeper interest in studying them.-(See Exodus x: 5, 14-15.)

In A. D. 591, a vast horde of locusts ravaged Italy. From the stench of their decaying carcasses arose a pestilence which carried off nearly a million men and beasts. In the Venetian Territory, in 1478, the same insect created a famine, during which thirty thousand persons died of starvation. So well did the Arabians know their power, that they make a locust say to Mahomet: "We are the army of the great God; we produce ninety-nine eggs; if the hundred were completed, we should consume the whole earth and all that is in it." Professor Riley estimated the annual loss from insect depredations in Missouri at fifteen to twenty millions of dollars, and the

losses in the United States probably amount to such an enormous sum, that nearly fifty million dollars might be saved through a more generally extended knowledge of the habits of insects. If insects play such a part in our economy, and, if the farmer's property is more liable to injury than that of any other class, who more than himself should be interested in them, and the remedies to abate the evil? There is no part of animated nature more vital to our welfare than insects, of which there are about fifty thousand species inhabiting the United States.

The study of entomology has been frequently looked down upon by the ignorant with ridicule, in consequence of the minuteness of many of its objects; yet it is exactly in these small members of creation that are exhibited the most wonderful adaptations of means to purposes, and the most amazing wisdom of the Creator!

Can the tiger, with its fierce leap, by which he catches his prey, and the retractile claw, by which he secures it, or the giraffe, with his long neck and tongue, by which he reaches the leaves, many feet from the ground, be compared with the spider? This insect lurks behind a screen of its own manufacture, ready to pounce upon and tie up any helpless insect, which conveys to it by the vibration of the web, the intelligence of its entanglement. In this web each single thread consists of many thousands of finer strands, a part only of which in the net of geometric spiders, the circles, is provided with a viscid covering to hold the captive. Which seems the greater manifestalion of divine wisdom: the clumsy she bear that brings lood to her hungry cubs, directly appealing to her maternal care, or the sand-wasp, which, after depositing an egg in a cell at the bottom of a cylindrical cavity in the sand, supplies the future larva with food in the form of insects? She so regulates the number of these, that the larva may have sufficient food; she stings the insects,

without killing them, as they would then putrefy, but just enough to keep them in a dormant state until wanted. How wonderful the instinct of a mother to provide food for offspring she will never behold! Every individual of the species, the descendant of countless ancestors, has thus fulfilled this maternal duty for ages past. Had the sand-wasp, for a single season, neglected its instinctive work, there would be no "horseguards" to keep the cow-fly under control, and in a measure to protect our cattle on the sea coast from their annoyance. The most efficient aids to man in keeping the increase of injurious insects within due limits, are their natural enemies of the insect world, and some of the insectivorous birds; for other birds devour indiscriminately, both the useful and injurious insects. There are also certain families of insects, which depredate upon the farmer's crops, and diminish his income, and certain other kinds, which prey upon these, and are therefore our friends and auxiliaries. Horticulture, it has been truly said, is a war with insects, and we must antagonize the former, and wage a relentless war against them, while we patronize, protect, and foster the useful insects to the best of our abillty.

If the farmer remains ignorant of these mutual relations between insects, a knowledge of the more common instances being readily acquired, how is he to discriminate between friend and foe, so that he may not be guilty of the evident impropriety of destroying both? How often has the useful little friendly lady-bug been mistaken for the parent of the plant-lice, and been pitilessly destroyed?

If he that makes two blades of grass to grow, where only one grew before, is a benefactor to mankind, he that protects both from needless destruction, is not less a benefactor! Therefore, while it is not within the power of man to wipe injurious insects from the face of

the earth, he may limit the destruction of property they cause, and it is to the farmer's interest, and is his duty, to wage a united war against them, knowing no tomorrow in its prosecution, but killing and destroying wherever and whenever possible, and employing every means in his power. Individual effort can avail little, and concerted action is necessary.

In our climate, insects generally have two broods in a season. Most of those which survive the winter in their perfect state are fertilized females, and all insects, if left unmolested early in the season, will propagate their species, and the second brood will outnumber the first a hundred or a thousand-fold.

While recommending a determined crusade against all insect pests, I would, from the same motive, protest against the pernicious habit, so common all over the country, of indiscriminately taking the life of the lower animals inhabiting the fields and woods; for the reason, that many reptiles, the toads and moles, are our innocent friends and aids. There are but very few venomous snakes, and the larger kinds, which are not insectivorous, destroy numbers of field rats and mice.

PARASITIC INSECTS.

We are occasionally subject to the visitation of an insect in vast numbers; but these generally bring with them the cause of their own limitation, or there would be no equilibrium in nature. Swarms of parasitic insects, finding an increased food supply, follow in their wake, and the farmer, aroused from his apathy, by finding his entire crops, and not merely a portion thereof, endangered, resorts to all sorts of devices to save them. dusts and sprinkles poisons, he digs circumscribing ditches with upright sides and pitfalls, and applies the torch and burning petroleum.

He

Previous to 1862, the European cabbage butterfly

(Pieris rapa), the parent of the cabbage-worm, was unknown in this country. It was at that time introduced into Canada. Finding in the cabbage fields near Quebec an abundance of food, and meeting no checks, it improved its opportunities and propagated its species to such an extent, as to cut short the cabbage crop of the vicinity in one season to the extent of forty thousand dollars.

Suddenly its own especial enemy, the little Chalcid fly (Pteromalus puparum) made its appearance, presumably direct from Europe; and in turn, finding its appropriate food in abundance, propagated its species so rapidly, that, now in sections where the cabbage-worm was most plentiful, neither the one nor the other is often seen; thus showing the beautiful working of checks and counter-checks in the general plan of nature.

THE MIGRATION OF INSECTS.

The number of injurious insects is on the increase all over the world. The interchange between different sections, different countries, and even different hemispheres, of noxious insects, indigenous to each, is constantly occurring, as shown by the case of the just-named Pieris rapa. The Colorado potato-beetle once gained a foothold in Germany; but through the paternal care of the government, the large potato field, where he was observed, was covered with inflammable material, and that country was promptly made too hot for him.

The Colorado potato-beetle has marched eastward to the coast, a curse and ravager of every farmer on its route, while the harlequin-bug (Strachia histrionica), coming north from its home in Mexico, will cross the ine of the other, unless it reaches a climatic limit to its onward progress. An abundance of food has recruited the ranks of noxious insects, and is still exerting the same influence. Before the introduction of the cab