1112 PRACTICE OF AGRICULTURE. Taut III 



Sect. II. Birds injurious to Agriculture' 



>. Of birds, tin.- most decidedly injurious to man are the different hawks and 

 kili>, as most of the species attack and devour young poultry. 



7640. Various methods Iiavc been proposed for remedying this evil, but they evince little acquaintance 

 with the habit* ol these birds. Mr Swainson recommenda that the prevalent custom, of nailing such as 

 have been killed against barn -doors or out bouses, be exchanged for the following: — III such parts of the 

 country a> arc frequented by these birds, lei two or three poles, ten 01 twelve (eel high, be placed in the 

 farmer's poultry yard, each pole being furnished with an iron spike six or eight inches long ; pass this 



.spike through the body Of B dead hawk in the direction of the back-hone : it will thus be firmly secured, 

 .mil give the bird an erect position ; the wings being free will be moved by every breeze, and their unna- 

 tural motion will prove the best scarecrow either for ravenous or granivorbus birds, more particularly the 

 latter. Destruction by the gun is of course the most effectual. 



7(>" 1 1 . Whether gramoormis birds are more injurious than beneficial to the farmer, is 

 very questionable. 



7644 The crow, rook, raven, sparrow, magpie, and starling are commonly called granivoroua ; yet this 

 is an error, for they are all omnivorous, that is, feeding both upon animal and vegetable substances, and 

 mure particularly upon insects Wt are annually told of large crops being either wholly or partially 

 destroyed by insects of some sort or other; but we never hear that these injuries have been occasioned by 

 lnr.lv These complaints have certainly been more numerous of late years than formerly, and this is 

 attributed by Mr. Swainson to the destruction of small birds as wastelands are brought into cultivation) ; 

 to the great diminution of rookeries ; and to the foolish prejudice which the generality of farmers have 

 taken up against these latter birds, which they destroy without mercy. In this instance we have been 

 less wise than our ancestors, who protected and cultivated them, and by whom they were justly considered 

 of the greatest benefit to mankind. Nature seems, indeed, to have pointed this out to us, for she has dis- 

 tributed the crow in all parts of the habitable world. Vet the farmer will enquire, " What good can these 

 birds do me, when they come on my newly sown land, and root up the seed P" The answer is very short 

 The crows and rooks do not come for the express purpose of eating or destroying the seed, but for 

 devouring the insects, snails, and grubs turned up by the plough or harrow; these are their favourite 

 food, and while so occupied, the small quantity of seed they may eat or displace is returned to the farmer 

 ten-fold by that saved from the insects. Wallis, in speaking of the destruction caused by the hedgechafl'er 

 or cockchattcr, says, that " whole meadows and corn-fields were destroyed by them ;" and judiciously 

 concludes by observing, " that the many rookeries with us is the reason why we have so few of these 

 destructive insects." [Hist, of Northumberland.) 



Sect. III. Insects' injurious to Agriculture- 



7643. Insects, above all other animals, are by far the most injurious to the agriculturist ; 

 not only from their numbers, but from their attacking the produce of the earth in all its 

 stages of growth and maturity. We have already pointed out the advantage, not to say 

 the necessity, of a certain knowledge being acquired respecting insects, by all persons 

 engaged in agricultural pursuits. We shall now explain, in popular language, the dif- 

 ferent tribes or orders into which they are divided ; the changes they undergo ; and the 

 injuries they produce to man, and the animals and vegetables which he cultivates. 

 Numerous insects, much more destructive than those we shall enumerate, are found in 

 other climates, but from which the British agriculturist has, happily, nothing to fear, and 

 therefore need not be acquainted with. The reader will, however, find much valuable 

 information respecting them concentrated in Kirby and Spence's Introduction to Ento- 

 mology, vol. i. 



Suhsect. 1. Physiology of Insects. 



76*4. Insects are distinguished from worms (/'ernies /..) by always having feet in their perfect state, 

 as the beetle, butterfly, See, Worms crawl upon their bellies and have no feet, as the earth-worm, slug, 

 snail, &c. The generality of insects have onlv six feet; but some few, generally called by this name, have 

 a gnat many, as the wood-louse, centipede. Sec. 



7645. Nearly all insects arc oviparous} that is, produced from an egg. These eggs arc seldom found 

 singly ; they are small in size, and do not grow. The eggs of some species arc hatched in a few days, 

 while those ol others remain during the winter, and the voting do not come forth until the season at which 

 the leaves nt the plants upon which they feed begin to expand. 



7646. '/'//,' second state of the insect is called the ervca, or larva in systematic language, and is known to 

 the vulgar by various names. Caterpillars are those larva; which are exposed, and feed upon leaves and 

 plants, as the caterpillar ol the common cabbage butterflv ( fig. 971. a). The larva- of beetles usually live 

 in the earth, in the trunks of trees, or ill the substance upon which they feed ; they are generally of a 

 whitish colour thick and clumsy in form, and are called grubs. The larva of the common cockchafer 

 (M- 970. 6/, and ol the nut-beetles [Jig. 970. , -\ are of this description ; while the name of maggots is usually 

 given to the larva- ol files, bees, am-. ftc., all of which live ill the same confined state as those of beetles 

 "J*" 1 ' „'•! ^T "! e * M *™«»«« insects are most voracious, and Consequently most destructive to plants 



r647. fvnen the larva has attorned to ,ts full she, it changes into the p .pa 'or chrysalis state This is 

 done in different situations, according to the tribes to which they belong. The chrysalis of butterflies 

 (ft).'. 971 0,6 are naked, and are either suspended or attached to trees, branches walls &c Those of 

 moth) arc either concealed in a case like the cocoon of the silkworm, or the caterpillar undergoes its 

 change in the earth. Ihe period in which insects remain in this state varies according to the species • but 

 in most cases they are inactive and torpid. ' ' 



7648. The imago, or perfect insert, is produced from the chrysalis, and is the onlv state in which all its 

 parts and members are fully developed. The appearance and economy of perfect insects in general is 

 totally different from those of the larva and pupa?, and it is onlv in it's final stage of existence that the 

 specie- can be ascertained. With the exception of such insects as form the a ptera of T.innsus all others 



are furnished with wings, either four or two in number. Some few exceptions, however occur to this 

 rule; Ihe female of the glow-worm and of some few moths are apterous, while many beetles [although 



furnished with hard winged cases are destitute of real wings. ° 



