CHINCH BUG. Afkropus leucopterus. This bug, when favorable seasons allow it to increase largely, is one of the most destructive of noxious insects. The Wheat Midge, the Grain Plant Louse, the Hessian Fly, destructive as they are in particular seasons, are, all combined, not to be so dreaded as this pest of the cereal crops. In significant as this minute scourge may seem, being little more than an eighth of an inch long, yet when they appear in countless millions, covering fields black, and sucking the life of the plants with their myriad beaks, the hopes of the farmer may well cease. Fortunately, they are assailed by nu merous foes, and by fun gus enemies. They may alfo be successfully destroyed by persistent effort. The illustrations give this insect in all its stages of transformation, the hair lines at the bottom of the perfect insect and at the sides of other figures showing the natural size.
Explanation: a, b, eggs; a, newly hatched larva; d, its tarsus (part of the foot to which the leg is joined); e, larva of the first moult; f, larva after second, moult; ,q, pupa; h, leg of perfect insect; j, being the same still more highly magnified; i, proboscis in beak. Dr. Riley gives the natural history of this pest, including some observations on insects in general, which is so terse and com prehensive that we quote it nearly entire: In the four great and extensive Orders of Insects, naipely, the Beetles (Coleoptera), the Clear-winged Flies (Hymenoptera), theScaly-winged Flies (Lep idoptera), and the Two-winged Flies (.Diptera), and in one of the four small orders in its restricted sense, namely, the Net-winged Flies, (Neuroptera) the insect usually lies still through out the pupa state, and is always so far from being able to eat or to evacuate, that both mouth and anus are closed up by membrane. In the three small orders, on the contrary, namely, that of the Straight-winged Flies in its most extensive sense (Crthoptera including Pseudo-neuroptera,), the Half-winged Bugs (Heteroptera) and the Whole-winged Bugs (Homoptera), the pupa is just as active and just as ravenous as either the larva or the perfectly developed and busy insect, and the, little creature never quits eating as long as the warm weather lasts, except for a day or so while it is accomplishing each of its successive three, four or five moults, As the Chinch Bug belongs to the Half-winged Bugs, it therefore continues to take food, with a few short intermissions, from the day when it hatches out from the egg to the day of its unlamented death. Most insects—irrespective of the Order to which they belong—require twelve months to go through the complete circle of their changes, from the day that the egg is laid to the day when the per fect insect perishes of old age and decrepitude. A few require three years, as for example the Round-headed Apple-tree Borer (Saperda bruit tita, Say) and the White Grub which produces the May-beetle (Lachnosterna quercina, Knoch). One species, the Thirteen-year Locust (Cicada tredecian, Riley) actually requires thirteen years to pass from the egg to the winged -state;, and another, the Seventeen-year Locust (Cicada seP temdecim, Linn.) the still longer period of seven teen years. On the other hand there are not a few who pass through all their three states in a few months, or even in a few weeks; so that in one and the same year there may be two, three or even four or five broods, one generated by the other and one succeeding another. For example, the Hessian Fly (Cecidomyia destructor, Say) the common Slug-worm of the Pear (Selandria cerasi, Peck) the Slug-worm of the Rose (Selandria rose, Harris) the Apple-worm and a few others, produce exactly two generations in one year, and hence may be termed two-brooded. Again, the Colorado Potato-beetle in Central Missouri is three-brooded, and not improbably, in more southerly regions is four-brooded. Lastly, the common House-fly, the Cheese-fly, the various species of Blow-flies and Meat-flies, and the mul tifarious species of Plant-lice (Aphis) produce an indefinite number of successive broods in a single year, sometimes amounting in the case of the last-named genus, as has been proved by actual experiment, to as many as nine. The Chinch Bug is two-brooded in North Illinois, and I find that it is likewise two-brooded in Missouri, and most probably in all the Middle states. Yet it is quite agreeable to analogy that in the more Southern states, it may be three-brooded. For instance, the large Polyphemus Moth is single brooded in the Northern and Middle states, and yet, two broods are sometimes produced in this state, while in the South it is habitually two brooded. Again, the moth known as the Poplar Spinner (Clostera Americana, Harris) is stated by Dr. Harris and Dr. Fitch to be only single brooded in Massachusetts and New York, the insect spinning up in September or October, passing the winter in the pupa state, and coming out in the winged form in the following June. But Dr. Harris—no doubt on the authority of Abbott—states that in Georgia this insect breeds twice a year; and I have proven that it does so breed in Missouri, having bred a number of cocoons which were formed by a second brood of larvae. It is quite reasonable, there fore, to infer that the Chinch Bug may produce even more than two broods in the more Southern states. It is these two peculiarities in the habits
of the Chinch Bug, namely, first, its continuing to take food from the day of its birth to the day of its death and, secondly, its being either two brooded or many brooded, that renders it so destructive and so difficult to combat. Such as survive the autumn, when the plants, on the sap of which they feed, are mostly dried up so as to afford them little or no nourishment, pass the winter in the usual torpid state, and always in the perfect or winged form, under dead leaves, under sticks of wood, under flat stones, in moss, in bunches of old dead grass or weeds or straw, ' and often in corn-stalks and corn-shucks. In the fall and winter of 1868, I repeatedly received corn-stalks that were crowded with them, and it was difficult to find a stalk in any field that did not reveal some of them, upon stripping off the leaves. I have even found them wintering in the gall made by the Solidago Gail-moth (Ode ,' chiagallce solidaginis,) described in the first report. In the winter all kinds of insect-devouring ani mals, such as birds, shrew-mice, etc., are hard put to it for food, and have to search every hole and corner for their appropriate prey. But no matter how closely they may thin out the Chinch Bugs, or how generally these insects may have been starved out by the autumnal droughts, there will always be a few left for seed next year. Suppose that there are only 2,000 Chinch Bugs remaining in the spring in a certain field, and that c ach female of the 2,000, as vegetation starts, raises a family of only 200, which is a low calculation. Then—allowing the sexes to be equal in number, whereas in reality the females are always far more numerous than the males— the first or spring brood will consist of 200,000, of which number 100,000 will be females. Here, if the species were single-brooded, the process would stop for the current year and 200,000 Chinch Bugs, in one field, would be thought nothing of by the Western farmer. But the species is not single-brooded and the process does not stop here. Each successive brood increases in numbers in geometrical progression, unless there be something to check their i. crease, until the second brood amounts to twenty mil lions, and the third brood to two thousand mil lions. We may form some idea of the meaning of two thousand millions of Chinch Bugs, when it is stated that that number of them, placed in a straight line, head and tail together, would just about reach from the surface of the earth to its central poi nt—a distance of 4,000 miles. Dr. ' Shimer. of Mt. Carroll, Ill., a careful observer, held that the insect only takes wing during the impulse of the sexual season. Dr. Riley, in relation to this matter, says: It is a notori ous fact that Chinch Bugs do not all mature at once, and if they took wing only when making their courtships, some of them would be flying during a period of several weeks and, as will be shown presently, there exists a dimorphous short winged form of the Chinch Bug, which cannot possibly • make any such aerial love trips. It seems more agreeable to analogy that they take wing only when they have become so unduly numerous that they are instinctively aware that they must either- emigrate or starve. Be this however as it may, the fact of their being as a genera] rule, unwilling to use their wings, is well known to every practical farmer. It has long been known that the Chinch Bug deposits its eggs underground and upon the roots of the plants which it infests, and that the young larva remain underground for some considerable time after they hatch out, sucking the sap film the roots. If, in the spring of the year, you pull up a wheat plant in a field badly infested with this insect, you will find hundreds of the, eggs attached to the roots; and at a somewhat later period, the young larvae may be found cluster ing upon the roots, and looking like so many moving little red atoms. The egg is so small as to be scarcely visible to the naked eye, of an oval shape, about four times as long as wide, of a pale amber-white color when first laid, but sub sequently assuming a reddish color, from the young larva showing through the transparent shell. As the mother Chinch Bug has to work her way underground in the spring of the year, in order to get at the roots upon which she pro poses to lay her eggs, it becomes evident at once, that the looser the soil is at this time of the year, the greater the facilities which are offered for the operation Hence the great of plowing land for spring grain in the preceding autumn, or, if plowed in the spring, rolling it repeatedly with a heavy roller after seeding. And hence the remark frequently made by far mers, that wheat harrowed in upon is corn ground, without any plowing at all, s far less infested with Chinch Bug than wheat put in upon land that has been plowed. There is another fact which has been repeatedly noticed by prac tical Eden. This insect can not live and thrive and multiply in land that is sopping with water; and it generally commences its operations in early spring upon those particular parts of every field where the soil is the loosest and the driest.