Online Encyclopedia

Search over 40,000 articles from the original, classic Encyclopedia Britannica, 11th Edition.

LOCUST

Online Encyclopedia
Originally appearing in Volume V16, Page 859 of the 1911 Encyclopedia Britannica.
» Make a correction to this article.
» Add information or comments to this article.
Spread the word: del.icio.us del.icio.us it!

LOCUST .' In its See also:

general acceptation this See also:term is applied only to certain See also:insects of the See also:order See also:Orthoptera, See also:family Acridiidae. The family Locustidae is now viewed zoologically in a sense that does not admit of the See also:species best known as " locusts " being included therein. The See also:idea of a very destructive See also:insect is universally associated with the term; therefore many orthopterous species that cannot be considered true locusts have been so-called; in See also:North See also:America it has even embraced certain See also:Hemiptera-Homoptera, belonging to the Cicadidae, and in some parts of See also:England cockchafers are so designated. In a more narrow See also:definition the attribute of See also:migration is associated with the destructive propensities, and it therefore becomes necessary that a true locust should be a migratory species of the family Acridiidae. Moreover, the term has yet a slightly different signification as viewed from the Old or New See also:World. In See also:Europe by a locust is meant an insect of large See also:size, the smaller allied species being ordinarily known as " grasshoppers," hence the " Rocky See also:Mountain locust " of North America is to Eastern ideas rather a See also:grasshopper than a locust. In Europe, and a greater See also:part of the Old World, the best known migratory locust is that which is scientifically termed Pachytylus cinerascens with which an allied species P. migratorius has been often confounded. Another locust found in Europe and neighbouring districts is Caloptenus italicus, and still another, Acridium peregrinum, has once or twice occurred in Europe, though its See also:home (even in a migratory sense) is more properly See also:Africa and See also:Asia. These practically include all the locusts of the Old World, though a migratory species of See also:South Africa known as Pachytylus pardalinus (presumed to be distinct from P. migratorius) should be mentioned. The Rocky Mountain locust of North America is Caloptenus spretus, and in that See also:continent there occurs an Acridium (A. americanum) so closely allied to A. peregrinum as to be scarcely distinct therefrom, though there it does not See also:manifest migratory tendencies. In the See also:West Indies and Central America A. peregrinum is also reported to occur. The See also:females excavate holes in the See also:earth in which the eggs are deposited in a See also:long cylindrical See also:mass enveloped in a glutinous secretion.

The See also:

young larvae See also:hatch and immediately commence their destructive career. As these insects are "hemimetabolic" there is no quiescent See also:stage; they go on increasing rapidly in size, and as they approach the perfect See also:state the rudiments of the wings begin to appear. Even in this stage their See also:locomotive See also:powers are extensive and their voracity See also:great. Once winged and perfect these powers become infinitely more disastrous, redoubled by the development of the migratory See also:instinct. The See also:laws regulating this instinct are not perfectly understood. See also:Food and temperature have a great See also:deal to do with it, and there is a tendency for the flights to take a particular direction, varied by the See also:physical circumstances of the breeding districts. So likewise each species has its See also:area of See also:constant location, and its area of extraordinary migration. Perhaps the most feasible of the suggestions as to the causes of the migratory impulse is that locusts naturally breed in dry sandy districts in which food is scarce, and are impelled to wander to procure the necessaries of See also:life; but against this it has been argued that swarms bred in a highly productive See also:district in which they have temporarily settled will seek the barren home of their ancestors. Another ingenious See also:suggestion is that migration is intimately connected with a dry See also:condition of the ,See also:atmosphere, urging them to move on until compelled to stop for food or procreative purposes. Swarms travel considerable distances, though probably generally fewer than See also:rood m., though sometimes very much more. As a See also:rule the progress is only See also:gradual, and this adds vastly to the devastating effects. When an extensive swarm temporarily settles in a district, all vegetation rapidly disappears, and then See also:hunger urges it on another stage.

The large Old World species, although undoubtedly phytoghagous, when compelled by hunger sometimes attack at least dry See also:

animal substances, and even See also:cannibalism has been asserted as an outcome of the failure of all other kinds of food. The length of a single See also:flight must depend upon ' The See also:Lat. locusts was first applied to a See also:lobster or other marine See also:shell-See also:fish and then, from its resemblance, to the insect. circumstances. From peculiarities in the examples of Acridium peregrinum taken in England in 186g, it has been asserted that they must have come See also:direct by See also:sea from the west See also:coast of Africa; and what is probably the same species has been seen in the See also:Atlantic at least 1200 M. from See also:land, in swarms completely covering the See also:ship; thus, in certain cases flight must be sustained for several days and nights together. The height at which swarms See also:fly, when their See also:horizontal course is not liable to be altered by mountains, has been very variously estimated at from 40 to 200 ft., or even in a particular See also:case to boo ft. The extent of swarms and the number of individuals in a swarm cannot be accurately ascertained. They come sometimes in such See also:numbers as to completely obscure the See also:sun, when.the See also:noise made by the rustling of the wings is deafening. Nevertheless some idea on this point may be formed from the ascertained fact that in See also:Cyprus in 1881, at the See also:close of the See also:season, 1,600,000,000 See also:egg-cases, each containing a considerable number of eggs, had been destroyed; the estimated See also:weight exceeding 1300 tons. Yet two years later, it is believed that not fewer than 5,076,000,000 egg-cases were again deposited in the See also:island. In Europe the best known and ordinarily most destructive species is Pachytylus cinerascens, and it is to it that most of the numerous records of devastations in Europe mainly refer, but it is probably not less destructive in many parts of Africa and Asia. That the arid See also:steppes of central Asia are the home of this insect appears probable; still much on this point is enveloped in uncertainty. In any case the area of permanent See also:distribution is enormous, and that of occasional distribution is still greater.

The former area extends from the parallel of 40° N. in See also:

Portugal, rising to 48° in See also:France and See also:Switzerland, and passing into See also:Russia at 55°, thence continuing across the See also:middle of See also:Siberia, north of See also:China to See also:Japan; thence south to the See also:Fiji Islands, to New See also:Zealand and North See also:Australia; thence again to See also:Mauritius .1 I.—Pachytylus migratorius. This and the dther figures are all natural size. and over all Africa to See also:Madeira. The See also:southern distribution is uncertain and obscure. Taking exceptional distribution, it is well known that it occasionally appears in the Britis?i Isles, and has in them apparently been noticed as far north as See also:Edinburgh; so also does it occasionally appear in Scandinavia, and it has probably been seen up to 63° N. in See also:Finland. Looking at this vast area, it is easy to conceive that an See also:element of uncertainty must always exist with regard to the exact determination of the species, and in Europe especially is this the case, because there exists a distinct species, known as P. migratorius, the migratory area of which appears to be confined to See also:Turkestan and eastern Europe. P. cinerascens is certainly the most See also:common of the " locusts " occasionally found in the See also:British Isles, and E. de Selys-Longchamps is of See also:opinion that it breeds regularly in See also:Belgium, whereas the true P. migratorius is only accidental in that See also:country. A South See also:African species allied to the preceding and provisionally identified as Pachytylus salcicollis is noteworthy from the manifesta- tion of the migratory instinct in immature wingless individuals. The families of young, after destroying the vegetation of a district, unite in a vast See also:army and move away in See also:search of fresh pastures, devastating the country as they go and proceeding of See also:necessity on See also:foot, hence they are known to the Dutch as " voetgangers." Travel-See also:ling northwards towards the centre of the continent, the home of their parents before migration, they are diverted from their course by no obstacles. Upon reaching a See also:river or stream they search the See also:bank for a likely spot to See also:cross, then fearlessly See also:cast themselves upon the See also:water where they See also:form floating islands of insects, most of which usually succeed in gaining the opposite bank, though many perish in the See also:attempt. Acridium peregrinum (fig. 2) can scarcely be considered even an accidental visitor to Europe; yet it has been seen in the south of See also:Spain, and in many examples spread over a large part of England in the See also:year 1869.

It is a larger insect than P. migratorius. There is every See also:

reason to believe that it is the most destructive locust through-out Africa and in See also:India and other parts of tropical Asia, and its ravages are as great as those of P. migratorius. Presumably it is the species occasionally noticed in a vast swarm in the Atlantic, very far from land, and presumably also it occurs in the West Indies and some parts of Central America. In the See also:Argentine See also:Republic a (possibly) distinct species (A. paranense) is the migratory locust. Caloptenus italicus (fig. 3) is a smaller insect, with a less extended area of migration; the destruction occasioned in the districts to which it is limited is often scarce less than that of its more terrible See also:allies. It is essentially a species of the Mediterranean district, and especially of the See also:European See also:side of that sea, yet it is also found in North Africa, and appears to extend far into southern Russia. Caloptenus spretus (fig. 4) is the " Rocky Mountain locust " or " hateful grasshopper " of the North See also:American continent. Though a comparatively small insect, not so large as some of the grass-hoppers of See also:English See also:fields, its destructiveness has procured for it great notoriety. By See also:early travellers and settlers the species was not recognized as distinct from some of its non-migratory congeners. But in 1877, See also:Congress appointed a See also:United States Entomological See also:Commission to investigate the subject.

The See also:

report of the commissioners (C.V See also:Riley, A. S. Packard and C. See also:Thomas) deals with the whole subject of locusts both in America and the Old World. C. spretus has its home or permanent area in the arid plains of the central region See also:east of the Rocky Mountains, extending slightly into the southern portion of See also:Canada; outside this is a wide fringe to which the term sub-permanent is applied, and this is again bounded by the limits of only occasional distribution, the whole occupying a large portion of the North American continent; but it is not known to have crossed the Rocky Mountains westward, or to have extended into the eastern states. As to remedial or preventive See also:measures tending to check the ravages of locusts, little unfortunately can be said; but anything that will apply to one species may be used with practically all. Something can be done (as is now done in Cyprus) by offering a See also:price for all the egg-tubes collected, which is the most direct manner of attacking them. Some little can be done by destroying the larvae while in an unwinged condition, and by digging trenches in the See also:line of See also:march into which they can fall and be drowned or otherwise put an end to. Little can be done with the winged hordes; See also:starvation, the outcome of their own See also:work, probably here does much. In South Africa some success has attended the spraying of the swarms with See also:arsenic. It has been shown that with all migratory locusts the breeding-places, or true homes, are comparatively barren districts (mostly elevated plateaus) ; hence the progress of colonization, and the See also:conversion of those heretofore barren plains into areas of fertility, may (and probably will) gradually lessen the evil. Locusts have many enemies besides See also:man.

Many birds greedily devour them, and it has many times been remarked that migratory swarms of the insects were closely followed by myriads of birds. a, a, a, See also:

Female in different posi- d, e show the earth partially retions, ovipositing. moved, to illustrate an egg- b, Egg-pod extracted from ground, with the end broken open. [ground. c, A few eggs lying loose on the Predatory insects of other orders also attack them, especially when they are in the unwinged condition. Moreover, they have still more deadly insect foes as parasites. Some attack the fully See also:developed winged insect. But the greater part attack the eggs. To such belong certain beetles, chiefly of the family Cantharidae, and especially certain two-winged flies of the family Bombyliidae. These latter, both in the Old and New World, must prevent vast quantities of eggs from producing larvae. The larger Old World species form articles of food with certain semi-civilized and See also:savage races, by whom they are considered as delicacies, or as part of See also:ordinary See also:diet, according to the See also:race and the method of preparation. (R. M'L.; R.

I. P.) LOCUST-See also:

TREE, or CAROB-TREE (Ceratonia siliqua), a member of the tribe Cassieae of the order See also:Leguminosae, the See also:sole species of its genus, and widely diffused spontaneously and by cultivation from Spain to the eastern Mediterranean regions. The name of the genus is derived from the often curved pod (Gr. Nepiznov, a little See also:horn). The See also:flowers have no petals and are polygamous or dioecious (male, female and hermaphrodite flowers occur). The See also:seed-pod is compressed, often curved, in-dehiscent and coriaceous, but with sweet pulpy divisions between the seeds, which, as in other genera of the Cassieae, are albuminous. The pods are eaten by men and animals, and in See also:Sicily a spirit and a See also:syrup are made from them. These husks being often used for See also:swine are called swine's See also:bread, and are probably referred to in the See also:parable of the Prodigal Son. It is also called St See also:John's bread, from a misunderstanding of Matt. iii. 4. The carob-tree was regarded by See also:Sprengel as the tree with which See also:Moses sweetened the See also:bitter See also:waters of Marah (Exod. xv. 25), as the kharriub, according to See also:Avicenna (p.

205), has the See also:

property of sweetening See also:salt and bitter waters. See also:Gerard (Herball, p. 1241) cultivated it in 1599, it having been introduced in 1570.

End of Article: LOCUST

Additional information and Comments

There are no comments yet for this article.
» Add information or comments to this article.
Please link directly to this article:
Highlight the code below, right click, and select "copy." Then paste it into your website, email, or other HTML.
Site content, images, and layout Copyright © 2006 - Net Industries, worldwide.
Do not copy, download, transfer, or otherwise replicate the site content in whole or in part.

Links to articles and home page are always encouraged.

[back]
LOCUS (Lat. for " place "; in Gr. rinros) 		[next]
LOD

Site © 2006 - Net Industries