Book IV. 



OF VERMIN. 



431 



ing eggs in the aututan. As these insects derive their nourishment from the juices of the plants which 

 they infest, nature has wisely ordained that the females should lay eggs in the autumn, though 

 they bring forth their young alive all the spring and summer months. This is to prevent them from 

 being starved for the want of food in winter. The young burst forth from their eggs in spring as soon as 

 there are leaves to subsist upon. Their noxious effects are well known to the gardener. They sometimes 

 migrate, and suddenly fall in showers on spots that were until then free from their ravages. Water 

 dashed with force from a syringe will prove as destructive to them as any thing when on trees ; and 

 smaller plants may be v/ashed witli lime-water, with tobacco- water, with elder-leaves infused in water, or 

 with common soap-suds, any of which will destroy the insects. The larvae of the lady-bird eat thousands 

 of them, some species of ichneumon and common ants also destroy them ; and some conjecture that it 

 would probably prove serviceable to scatter ants, v/hich may always be procured in abundance, upon in- 

 fested trees. The aphides sometimes settle upon the tops of beans, covering them so thickly as to make 

 them appear quite black : in such cases the crops may often be preserved by cutting ott the tops^ a practice 

 which is likewise adopted independently of this pest requiring it, for the purpose of increasing the 

 yield of beans. {Dr. S/crimshire's Essays Introd. to Nat. Hist., vol. i. p. 149.) The rose-tree is, after a 

 mild spring, greatly injured by a species of aphis {A. rosce). The best mode of remedying this evil is to 

 lop offthe infected shoots before the insects are greatly multiplied, repeating the same oijeration before 

 the eggs are deposited. By the first pruning a very numerous parent mcrease will be prevented, and by 

 the second, the following year's supply may, in a great measure, be cut off. If it were not for the 

 numerous enemies to which the aphis is exposed, their wonderful fecundity is such that the leaves, 

 branches, and stems of every plant would be totally covered with them. Myriads of insects of different 

 classes, of different genera, and of different species, seem to be produced for no other purpose than to 

 devour the aphis. On every leaf inhabited by them we find caterpillars of different kinds. These 

 teed not upon the leaves, but upon the pucerons, whom they devour with an almost incredible rapacity. 

 Some of these larvae; are transformed into insects with two wings, others into flies with four wings, and 

 others into beetles. While in the larva state one of these glutinous insects will suck out the vitals of 

 twenty pucerons in a quarter of an hour. Reaumur supplied a single caterpillar with more than a 

 hundred pucerons, every one of which it devoured in less than three hours. 



2243. The chertnes {fig. Wl. c, d, e) is a genus very generally confounded with aphis; it also inhabits 

 the leaves and stems of plants, and by its punctures, produces excrescences and protuberances of various 

 sizes and shapes, which are generally found to enclose either the egg or immature insect, in the larva 

 state ; it is six-footed, hairy or woolly, and without wings ; and in the pupa are two protuberances from 

 the thorax, which are the rudiments of the future wings. The winged insects (c) leap or spring with great 

 agility, and infest a number of different trees and plants : the females {d), by means of a tube at the ter- 

 mination of their bodies, insert their eggs under the surface of the leaves ; and the worms, when hatched, 

 give rise to those tubercles, or galls, with whicli the leaves of the ash, the fir, and other trees, are some- 

 times almost entirely covered. The old females, before depositing their eggs, expand to a comparatively- 

 large size {e). 



2244. The thrips {fig. 401. /) genus consists of very small insects, found chiefly on the flowers of plants, 

 and, excepting when very numerous, are not very detrimental. The natural size is very minute, and there- 

 fore to search for this insect the gardener should use a magnifying glass. 



2245. Of the cochineal or coccus genus {fig. 401. g) there are several species very injurious in gardens, the 

 peach, vine, pine, and orange bugs. They are very well known to gardeners, and are almost exclusively 

 found in hot-houses. The males are active, but the females are very inert, being generally fixed to differ- 

 ent parts of plants. The eggs, of their natural size, are mere dots, magnified {g) they appear of an oval 

 shape ; the larva is proportionally small, but magnified {h) is oblong and roundish ; the males {i) only have 

 wings, and require to be magnified to show their form {k) ; the female attains a considerable size {!), and, 

 when hatching, becomes enveloped in a case of wool {m). Brushing off these creatures is the only effectual 

 remedy, and, if set about at once and persevered in, will save the trouble of many prescribed washes and 

 powders, whicli are mere palliatives. 



2246. The lepidoptera contains the butterfly, moth, and hawk-moth ; they have all four 

 wings covered with scales or a sort of farina ; they have a mouth, with palpi, a spiral 

 tongue ; the body covered with hair. The scales resemble feathers ; they lie over one 

 another in an imbricated manner, the shaft towards the body of the insect, and the ex- 

 pansion towards the end of the wing, reflecting the most brilliant colors. 



2247, Of the butterfly genus {Papilio, Ij.) many thousand species are known in Europe, and in England 

 alone more than eleven hundred have been collected by a celebrated entomologist. 



9248. TTie larvce, or young, of the different kinds of butterflies and moths, when in that state in which 

 they come from the egg, are called caterpillars. These, which are very minute at first, feed generally on 

 the leaves of vegetables, and increase in size. They cast their skins occasionally, and sometimes chango 

 in color and markings, but never in their general appearance or in their habits. Eating seems to be their 

 sole employment J and when they meet with food that suits their palate, they are extremely voracious, 

 committing great havoc in gardens. But the same cause which restrains the depredations of the aphides 

 and other insects has also set bounds to the destruction occasioned by the caterpillar, who has myriads of in- 

 ternal as well as external enemies. Many flies deposit their eggs in the bodies of caterpillars. From these 

 eggs proceed small maggots, which gradually devour the vitals of the animal in which they reside. When 

 about to be transformed into chrysalids, they pierce the skin of the caterpillar, spin their pods, and remain 

 on the empty skin till they assume the form of flies, and escape into the air to perform the same cruel 

 office to another unfortunate larva. Every person must recollect to have seen the colewort or cabbage 

 caterpillar stuck upon old walls, or the windows of country-cottages, totally covered with these chrysalids, 

 which have the form of small maggots, and are of a fine yellow color. One of the most formidable ene- 

 mies of the caterpillar is a black worm, with six crustaceous legs: it is longer and thicker than an ordinary- 

 sized caterpillar. In the fore part of the head it has two curved pincers, with which it quickly pierces the 

 belly of a caterpillar, and never quits the prey till it is entirely devoured. The largest caterpillar is not 

 sufficient to nourish this larva for a single day; for it daily kills and eats several of them. These 

 gluttons, when gorged with food, become inactive, and almost motionless ; when in this saUated con- 

 dition, young larvee of the same species attack and devour them. Of all trees, the oak perhaps nourishes 

 the greatest number of different caterpillars, as well as of different insects. Among others, the oak is 

 inhabited by a large and beautiful beetle. This beetle frequents the oak, probably because that tree is 

 inhabited by the greatest number of caterpillars. It marches from branch to branch, and, when dis- 

 posed for food, attacks and devours the first caterpillar that comes in its way. 



2249. Chrysalis state. When full grown, the caterpillar seeks some retreat, to prepare for an important 

 change, viz. from the soft caterpillar, possessing motion and feeding so voraciously, to the hard chrysalis, 

 fixed immoveably, and sustained without food. The retreat that is chosen and the preparation that is made 

 for this important change vary essentially in different species : some retire to the sheltered situations of 

 houses, walls, and other buildings ; some bury themselves in the ground ; some wrap themselves up in leaves ; 

 others attach themselves to the stalks of plants ; while others again eat into the stems of vegetables, or the 

 very heart of trees, and there undergo their metamorphosis. Although each kind of caterpillar seeks a 

 diflferent retreat, yet all of the same species seek the same, and adopt the same means of preservation. 



