The Book of Roses. Francis ParkmanЧитать онлайн книгу.
genus Macrodaclylus of Latreille. Common as this insect is in the vicinity of Boston, it is, or was a few years ago, unknown in the northern and western parts of Massachusetts, in New Hampshire, and in Maine. It may, therefore, be well to give a brief description of it. This beetle measures seven-twentieths of an inch in length. Its body is slender, tapers before and behind, and is entirely covered with very short and close ashen-yellow down; the thorax is long and narrow, angularly widened in the middle of each side, which suggested the name subspinosa, or somewhat spined; the legs are slender, and of a pale-red color; the joints of the feet are tipped with black, and are very long; which caused Latreille to call the genus Macrodactylus: that is, long toe, or long foot.
"The natural history of the rose-chafer, one of the greatest scourges with which our gardens and nurseries have been afflicted, was for a long time involved in mystery, but is at last fully cleared up. The prevalence of this insect on the rose, and its annual appearance coinciding with the blossoming of that flower, have gained for it the popular name by which it is here known. For some time after they were first noticed, rose-bugs appeared to be confined to their favorite, the blossoms of the rose; but within forty years they have prodigiously increased in number, have attacked at random various kinds of plants in swarms, and have become notorious for their extensive and deplorable ravages. The grape-vine, in particular, the cherry, plum, and apple trees, have annually suffered by their depredations: many other fruit-trees and shrubs, garden vegetables and corn, and even the trees of the forest and the grass of the fields, have been laid under contribution by these indiscriminate feeders, by whom leaves, flowers, and fruits are alike consumed. The unexpected arrival of these insects in swarms at their first coming, and their sudden disappearance at the close of their career, are remarkable facts in their history. They come forth from the ground during the second week in June, or about the time of the blossoming of the damask-rose, and remain from thirty to forty days. At the end of this period the males become exhausted, fall to the ground, and perish; while the females enter the earth, lay their eggs, return to the surface, and, after lingering a few days, die also.
"The eggs laid by each female are about thirty in number, and are deposited from one to four inches beneath the surface of the soil: they are nearly globular, whitish, and about one-thirtieth of an inch in diameter, and are hatched twenty days after they are laid. The young larvæ begin to feed on such tender roots as are within their reach. Like other grubs of the Scarabæians, when not eating they lie upon the side, with the body covered, so that the head and tail are nearly in contact: they move with difficulty on a level surface, and are continually falling over on one side or the other. They attain their full size in the autumn, being then nearly three-quarters of an inch long, and about an eighth of an inch in diameter. They are of a yellowish-white color, with a tinge of blue towards the hinder extremity, which is thick, and obtuse or rounded. A few short hairs are scattered on the surface of the body. There are six short legs; namely, a pair to each of the first three rings behind the head: and the latter is covered with a horny shell of a pale rust color. In October they descend below the reach of frost, and pass the winter in a torpid state. In the spring they approach towards the surface, and each one forms for itself a little cell of an oval shape by turning round a great many times, so as to compress the earth, and render the inside of the cavity hard and smooth. Within this cell the grub is transformed to a pupa during the month of May by casting off its skin, which is pushed downwards in folds from the head to the tail. The pupa has somewhat the form of the perfected beetle, but is of a yellowish-white color; its short, stump-like wings, its antennæ, and its legs, are folded upon the breast; and its whole body is enclosed in a thin film, that wraps each part separately. During the month of June, this filmy skin is rent: the included beetle withdraws from its body and its limbs, bursts open its earthen cell, and digs its way to the surface of the ground. Thus the various changes, from the egg to the full development of the perfected beetle, are completed within the space of one year.
"Such being the metamorphoses and habits of these insects, it is evident that we cannot attack them in the egg, the grub, or the pupa state: the enemy in these stages is beyond our reach, and is subject to the control only of the natural but unknown means appointed by the Author of Nature to keep the insect tribes in check. When they have issued from their subterranean retreats, and have congregated upon our vines, trees, and other vegetable productions, in the complete enjoyment of their propensities, we must unite our efforts to seize and crush the invaders. They must indeed be crushed, scalded, or burned, to deprive them of life; for they are not affected by any of the applications usually found destructive to other insects. Experience has proved the utility of gathering them by hand, or of shaking them or brushing them from the plants into tin vessels containing a little water. They should be collected daily during the period of their visitation, and should be committed to the flames, or killed by scalding water. The late John Lowell, Esq., states that, in 1823, he discovered on a solitary apple-tree the rose-bugs 'in vast numbers, such as could not be described, and would not be believed if they were described, or at least none but an ocular witness could conceive of their numbers. Destruction by hand was out of the question,' in this case. He put sheets under the tree, shook them down, and burned them.
"Dr. Green of Mansfield, whose investigations have thrown much light on the history of this insect, proposes protecting plants with millinet, and says that in this way only did he succeed in securing his grape-vines from depredation. His remarks also show the utility of gathering them. 'Eighty-six of these spoilers,' says he, 'were known to infest a single rose-bud, and were crushed with one grasp of the hand.' Suppose, as was probably the case, that one-half of them were females: by this destruction, eight hundred eggs, at least, were prevented from becoming matured. During the time of their prevalence, rose-bugs are sometimes found in immense numbers on the flowers of the common white-weed, or ox-eyed daisy (Chrysanthemum leucanihemum); a worthless plant, which has come to us from Europe, and has been suffered to overrun our pastures and encroach on our mowing-lands. In certain cases, it may become expedient rapidly to mow down the infested white-weed in dry pastures, and consume it, with the sluggish rose-bugs, on the spot.
"Our insect-eating birds undoubtedly devour many of these insects, and deserve to be cherished and protected for their services. Rose-bugs are also eaten greedily by domesticated fowls; and when they become exhausted and fall to the ground, or when they are about to lay their eggs, they are destroyed by moles, insects, and other animals, which lie in wait to seize them. Dr. Green informs us that a species of dragon-fly, or devil's-needle, devours them. He also says that an insect, which he calls the enemy of the cut-worm (probably the larva of a Carabus or predaceous ground-beetle), preys on the grubs of the common dor-bug. In France, the golden ground-beetle (Carabus auratus) devours the female dor, or chafer, at the moment when she is about to deposit her eggs. I have taken one specimen of this fine ground-beetle in Massachusetts; and we have several other kinds equally predaceous, which probably contribute to check the increase of our native Melolonthians."
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