1. The Coccus he&perid/tm, or green-house bug, which chiefly infests orange, and other plants in green-houses. When young, it runs upon the trees, but afterwards settles on some leaf, where it deposits a great number of eggs, and dies.
2. The Coccus malorum, or ap-pie-tree Coccus, which, as soon as it fixes on a tree, communicates a corrosive ichor, that affects the bark, even after the insect is removed, in a manner similar to a gangrene so that it becomes blotched, and full of deep holes, in consequence of which, it decays and dies. This insect preferably attacks the tender buds of young trees, and may be easily removed by means of a hard painter's brush, without injury to the plant, if it has not 1 ad sufficient time to bury itself in the bark. It also settles in such cavities as are frequently produced in the stems of trees, by incautiously tearing off the branches, or by any other wound. Being thus protected from the rain, these verC 3 min rain can only be eradicated, by scooping them out, cutting off every irregular prominence, scrap-ing off all loose scales from the bark, and then covering it with Mr.Forsyth's composition, which will not only defend it against their devastations, but, by bringing on a smooth, clean bark, will admit of its being washed and cleaned afterwards, without difficulty. This process will preserve the tree, both from the depredations of these insects, and from those of many others, which shelter themselves in the inequalities of a rough bark, and will at the same time give it additional health and vigour. See vol. i. p. 88.
3. The Peach Coccus, which Dr. Anderson calls gall-nut, settles only on the twigs .of peach-trees, where it deposits innumerable eggs. These may be eradicated by carefully brushing the twigs, in the spring, with a hard brush, in the direction of the buds ; by which simple means many of them may be detached, and their numbers greatly reduced. Where the in-sects are very close together at the points of the twigs, the latter may be cut off, and carried out of the garden; for,if thrown on the ground, the former will re-ascend. But, if they are exceedingly numerous, all the young trees may even be lopped, especially if Mr. Forsyth's plaster be applied to the wounds. Although, by this operation, the fruit will be lost for that season, yet the tree will acquire considerable strength, and be in the finest order next year. Notwithstanding all these precautions, if will be necessary to examine the tree, with the utmost attention, towards the end of April, or beginning of May : for, at that season, the female vermin attain c o c their full growth, so as to be .easily perceptible; when each of them should be carefully detached from the branch to which it adheres, by means of a blunt knife with a very thin blades then deposited in a vessel, and removed from the garden.
Naturalists have computed, that the generation of 3000 insects will be prevented by the destruction of each female gall-nut, so that great progress may be made in a very, short time. Thus, if that necessary operation be performed with car , very few will escape; and if the eggs also be properly extirpated, all future trouble respecting this insert will be effectually obviated.
.4, The Coccus Phalaridis,which is found on the phalaris or canary-, grass, and is originally a native of the Canary Islands, but has become naturalized.
5. The Coccus Cacti, or cochineal insect, which is a native of the warmer parts of America. -See Cochineal.
8. The Coccus Polonicus, or scarlet grain of Poland, is found there in great abundance on the roots pf the polygonum cocciferum. It is also called the cochineal of the north; as, contrary to the nature of the American insect, it thrives only in cold climates. It is collected for the use of dyers; though it yields not only smaller crops, and is gathered with more diffculty, but the drug also is much inferior to the true cochienal..