1822

ARBORETUM AND FRUTICETUM.

PART III.

a red head, and about ljin.long. In this state it con-tinues four years, duringwhich time it commits themost destructive ravages onthe roots, not only of grass,but of all other plants andyoung trees. When full

grown, the larvae dig in the

earth to the almost incredible depth of 5 ft. or 6 ft., spin a smooth case,and then change into a chrysalis. In this state they remain till the fol-lowing spring, when the perfect insect comes from the ground, and com-mences an immediate attack on the leaves of trees; and, according toSalisbury, the leaves of the oaks in Richmond Park were, during one sum-mer, so eaten by it, that scarcely an entire leaf was left. The most remarkableaccount of the ravages of these insects is, however, given by Molyneux, inone of the early volumes of the Philosophical Transactions, in which their ap-pearance in the county of Galway, in Ireland, in 1688, is narrated. Theywere seen in the day-time perfectly quiet, and hanging from the boughs' inclusters of thousands, clinging to each other like bees when they swarm; butdispersing towards sunset, with a strange humming noise, like the beating ofdistant drums; and in such vast numbers, that they darkened the air for thespace of two or three miles square; and the noise they made in devouring theleaves wds so great, as to resemble the distant sawing of timber. In a veryshort time the leaves of all the forest trees, for some miles were destroyed,leaving the trees as bare and desolate in the middle of summer as they wouldhave been in winter : they also entered the gardens, and attacked the fruittrees in the same manner. Their multitudes spread so exceedingly, that theyinfested houses, and became extremely offensive and troublesome. They weregreedily devoured by the swine and poultry, which watched under the treesfor their falling, and became fat on this unusual food : even the people adopteda mode of dressing them, and used them as food. Towards the end of thesummer they disappeared suddenly, and no traces were perceived of them theensuing year. (Phil. Trans., xix. p. 743., &c.) About the middle of the lastcentury, 80 bushels of these beetles were gathered on one farm near Norwich.(See Encyc. of Agri., ed. 2., p. 1116.) The best method of destroying theseinsects is to shake the branches on which they hang at noonday, when theyare in a state of stupor, and then to sweep them up and carry them away; or,torches may be held under the trees, which will stupify the beetles, andoccasion them to fall. Birds are very useful in destroying these noxious insects.In the Magazine of Natural History, vol. v. p. 65., a story is told of a gentle-man, who, finding his oak trees stripped of their leaves in the middle of sum-mer, suspected some rooks of having destroyed them. “That the oaks werenearly bare was beyond dispute ; and he had himself seen the rooks settlingon them, and pecking away right and left with their bills. War was thereforedeclared against the rooks; but, fortunately, before hostilities were commenced,the gentlemen was convinced, by some one who knew more of natural historythan himself, that the rooks were not in fault: on the contrary, they had only-flocked to the trees for the sake of devouring the myriads of cockchafers, andof the larvae of moths, which were the real depredators.” Blackbirds act inthe same manner; and the Rev. W. T. Bree relates an instance of these birdsstocking up the grass to find the larvae of the cockchafer, in a garden wherethere was plenty of ripe fruit. ( See Mag. Nat. Hist.,yo 1. vi. p. 518.) The leavesare also devoured by the larvae of one of the species of flea weevil (Orch&tesquercus). A'grilus viridis, Cryptorhyncus quercus, and Acalles roboris are alsocoleopterous insects found among the leaves of the oak. Aleyrodes proletella,a minute but very interesting homopterous insect, also feeds upon the leavesof the oak. ( Reaumur, Memoires, tom.ii. pi. 25.)

The young Stems and Buds of the Oak are also infested by various species of