Part 31

FLY (formed on the root of the supposed original Teut. _fleugan_, to fly), a designation applied to the winged or perfect state of many insects belonging to various orders, as in butterfly (see LEPIDOPTERA), dragon-fly (q.v.), may-fly (q.v.), caddis-fly (q.v.), &c.; also specially employed by entomologists to mean any species of the two-winged flies, or Diptera (q.v.). In ordinary parlance _fly_ is often used in the sense of the common house-fly (_Musca domestica_); and by English colonists and sportsmen in South Africa in that of a species of tsetse-fly (_Glossina_), or a tract of country ("belt") in which these insects abound (see TSETSE-FLY).

Apart from the house-fly proper (_Musca domestica_), which in England is the usual one, several species of flies are commonly found in houses; e.g. the _Stomoxys calcitrans_, or stable-fly; _Pollenia rudis_, or cluster-fly; _Muscina stabulans_, another stable-fly; _Calliphora erythrocephala_, blue-bottle fly, blow-fly or meat-fly, with smaller sorts of blue-bottle, _Phormia terraenovae_ and _Lucilia caesar_; _Homalomyia canicularis_ and _brevis_, the small house-fly; _Scenopinus fenestralis_, the black window-fly, &c. But _Musca domestica_ is far the most numerous, and in many places, especially in hot weather and in hot climates, is a regular pest. Mr L.O. Howard (Circular 71 of the Bureau of Entomology U.S. Dept. of Agriculture, Washington, 1906) says that in 1900 he made a collection of the flies in dining-rooms in different parts of the United States, and out of a total of 23,087 flies, 22,808 were the common house-fly. Its geographical distribution is of the widest, and its rapidity of breeding, in manure and door-yard filth, so great that, as a carrier of germs of disease, especially cholera and typhoid, the house-fly is now recognized as a potent source of danger; and various sanitary regulations have been made, or precautions suggested, for getting rid of it. These are discussed by Mr Howard in the paper referred to, but in brief they all amount to measures of general hygiene, and the isolation, prompt removal, or proper sterilization of the animal or human excrement in which these flies breed.

FLYCATCHER, a name introduced in ornithology by Ray, being a translation of the _Muscicapa_ of older authors, and applied by Pennant to an extremely common English bird, the _M. grisola_ of Linnaeus. It has since been used in a general and very vague way for a great many small birds from all parts of the world, which have the habit of catching flies on the wing. Ornithologists who have trusted too much to this characteristic and to certain merely superficial correlations of structure, especially those exhibited by a broad and rather flat bill and a gape beset by strong hairs or bristles, have associated under the title of _Muscicapidae_ an exceedingly heterogeneous assemblage of forms much reduced in number by later systematists. Great advance has been made in establishing as independent families the _Todidae_ and _Eurylaemidae_, as well as in excluding from it various members of the _Ampelidae_, _Cotingidae_, _Tyrannidae_, _Vireonidae_, _Mniotiltidae_, and perhaps others, which had been placed within its limits. These steps have left the _Muscicapidae_ a purely Old-World family of the order _Passeres_, and the chief difficulty now seems to lie in separating it from the _Campephagidae_ and the _Laniidae_. Only a very few of the forms of flycatchers (which, after all the deductions above mentioned, may be reckoned to include some 60 genera or subgenera, and perhaps 250 species) can here be even named.[1]

The best-known bird of this family is that which also happens to be the type of the Linnaean genus _Muscicapa_--the spotted or grey flycatcher (_M. grisola_). It is a common summer visitant to nearly the whole of Europe, and is found throughout Great Britain, though less abundant in Scotland than in England, as well as in many parts of Ireland, where, however, it seems to be but locally and sparingly distributed. It is one of the latest migrants to arrive, and seldom reaches the British Islands till the latter part of May, when it may be seen, a small dust-coloured bird, sitting on the posts or railings of gardens and fields, ever and anon springing into the air, seizing with an audible snap of its bill some passing insect as it flies, and returning to the spot it has quitted, or taking up some similar station to keep watch as before. It has no song, but merely a plaintive or peevish call-note, uttered from time to time with a jerking gesture of the wings and tail. It makes a neat nest, built among the small twigs which sprout from the bole of a large tree, fixed in the branches of some plant trained against a wall, or placed in any hole of the wall itself that may be left by the falling of a brick or stone. The eggs are from four to six in number, of a pale greenish-blue, closely blotched or freckled with rust-colour. Silent and inconspicuous as is this bird, its constant pursuit of flies in the closest vicinity of houses makes it a familiar object to almost everybody. A second British species is the pied flycatcher (_M. atricapilla_), a much rarer bird, and in England not often seen except in the hilly country extending from the Peak of Derbyshire to Cumberland, and more numerous in the Lake District than elsewhere. It is not common in Scotland, and has only once been observed in Ireland. More of a woodland bird than the former, the brightly-contrasted black and white plumage of the cock, together with his agreeable song, readily attracts attention where it occurs. It is a summer visitant to all western Europe, but farther eastward its place is taken by a nearly allied species (_M. collaris_) in which the white of the throat and breast extends like a collar round the neck. A fourth European species (_M. parva_), distinguished by its very small size and red breast, has also strayed some three or four times to the extreme south-west of England. This last belongs to a group of more eastern range, which has received generic recognition under the name of _Erythrosterna_, and it has several relations in Asia and particularly in India, while the allies of the pied flycatchers (_Ficedula_ of Brisson) are chiefly of African origin, and those of the grey or spotted flycatcher (_Muscicapa_ proper[2]) are common to the two continents.

One of the most remarkable groups of _Muscicapidae_ is that known as the paradise flycatchers, forming the genus _Tchitrea_ of Lesson. In nearly all the species the males are distinguished by the growth of exceedingly long feathers in their tail, and by their putting on, for some part of the year at least, a plumage generally white, but almost always quite different from that worn by the females, which is of a more or less deep chestnut or bay colour, though in both sexes the crown is of a glossy steel-blue. They are found pretty well throughout Africa and tropical Asia to Japan, and seem to affect the deep shade of forests rather than the open country. The best-known species is perhaps the Indian _T. paradisi_; but the Chinese _T. incii_, and the Japanese _T. princeps_, from being very commonly represented by the artists of those nations on screens, fans and the like, are hardly less so; and the cock of the last named, with his bill of a pale greenish-blue and eyes surrounded by bare skin of the same colour--though these are characters possessed in some degree by all the species--seems to be the most beautiful of the genus. _T. bourbonnensis_, which is peculiar to the islands of Mauritius and Reunion, appears to be the only species in which the outward difference of the sexes is but slight. In _T. corvina_ of the Seychelles, the adult male is wholly black, and his middle tail-feathers are not only very long but very broad. In _T. mutata_ of Madagascar, some of the males are found in a blackish plumage, though with the elongated median rectrices white, while in others white predominates over the whole body; but whether this sex is here actually dimorphic, or whether the one dress is a passing phase of the other, is at present undetermined. Some of the African species, of which many have been described, seem always to retain the rufous plumage, but the long tail-feathers serve to mark the males.

A few other groups are distinguished by the brilliant blue they exhibit, as _Myiagra azurea_, and others as _Monarcha_ (or _Arses_) _chrysomela_ by their golden yellow. The Australian forms assigned to the _Muscicapidae_ are very varied. _Sisura inquieta_ has some of the habits of a water-wagtail (_Motacilla_), and hence has received the name of "dishwasher," bestowed in many parts of England on its analogue; and the many species of _Rhipidura_ or fantailed flycatchers, which occur in various parts of the Australian Region, have manners still more singular--turning over in the air, it is said, like a tumbler pigeon, as they catch their prey; but concerning the mode of life of the majority of the _Muscicapidae_, and especially of the numerous African forms, hardly anything is known. (A. N.)

FOOTNOTES:

[1] Of the 30 genera or subgenera which Swainson included in his _Natural Arrangement and Relations of the Family of Flycatchers_ (published in 1838), at least 19 do not belong to the _Muscicapidae_ at all, and one of them, _Todus_, not even to the order _Passeres_. It is perhaps impossible to name any ornithological work whose substance so fully belies its title as does this treatise. Swainson wrote it filled with faith in the so-called "Quinary System"--that fanciful theory, invented by W.S. Macleay, which misled and kept back so many of the best English zoologists of his generation from the truth,--and, unconsciously swayed by his bias, his judgment was warped to fit his hypothesis.

[2] By some writers this section is distinguished as _Butalis_ of Boie, but to do so seems contrary to rule.

FLYGARE-CARLEN, EMILIE (1807-1892), Swedish novelist, was born in Stromstad on the 8th of August 1807. Her father, Rutger Smith, was a retired sea-captain who had settled down as a small merchant, and she often accompanied him on the voyages he made along the coast. She married in 1827 a doctor named Axel Flygare, and went with him to live in the province of Smaland. After his death in 1833 she returned to her old home and published in 1838 her first novel, _Waldemar Klein_. In the next year she removed to Stockholm, and married, in 1841, the jurist and poet, Johan Gabriel Carlen (1814-1875). Her house became a meeting-place for Stockholm men of letters, and for the next twelve years she produced one or two novels annually. The premature death of her son Edvard Flygare (1829-1853), who had already published three books, showing great promise, was followed by six years of silence, after which she resumed her writing until 1884. The most famous of her tales are _Rosen pa Tistelon_ (1842; Eng. trans. _The Rose of Tistelon_, 1842); _Enslingen pa Johannesskaret_ (1846; Eng. trans. _The Hermit_, 4 vols., 1853); and _Ett Kopemanshus i skargarden_ (1859; _The Merchant's House on the Cliffs_). Fru Carlen published in 1878 _Minnen af svenskt forfattarlif_ 1840-1860, and in 1887-1888 three volumes of _Efterskord fran en 80- arings forfattarbana_, containing her last tales. She died at Stockholm on the 5th of February 1892. Her daughter, Rosa Carlen (1836-1883), was also a popular novelist.

Emilie Flygare-Carlen's novels were collected in thirty-one volumes (Stockholm, 1869-1875).

FLYING BUTTRESS, in architecture, the term given to a structural feature employed to transmit the thrust of a vault across an intervening space, such as an aisle, chapel or cloister, to a buttress built outside the latter. This was done by throwing a semi-arch across to the vertical buttress. Though employed by the Romans and in early Romanesque work, it was generally masked by other constructions or hidden under a roof, but in the 12th century it was recognized as rational construction and emphasized by the decorative accentuation of its features, as in the cathedrals of Chartres, Le Mans, Paris, Beauvais, Reims, &c. Sometimes, owing to the great height of the vaults, two semi-arches were thrown one above the other, and there are cases where the thrust was transmitted to two or even three buttresses across intervening spaces. As a vertical buttress, placed at a distance, possesses greater power of resistance to thrust than if attached to the wall carrying the vault, vertical buttresses as at Lincoln and Westminster Abbey were built outside the chapterhouse to receive the thrust. All vertical buttresses are, as a rule, in addition weighted with pinnacles to give them greater power of resistance.

FLYING COLUMN, in military organization, an independent corps of troops usually composed of all arms, to which a particular task is assigned. It is almost always composed in the course of operations, out of the troops immediately available. Mobility being its _raison d'etre_, a flying column is when possible composed of picked men and horses accompanied with the barest minimum of baggage. The term is usually, though not necessarily, applied to forces under the strength of a brigade. The "mobile columns" employed by the British in the South African War of 1899-1902, were usually of the strength of two battalions of infantry, a battery of artillery, and a squadron of cavalry--almost exactly half that of a mixed brigade. Flying columns are mostly used in savage or guerrilla warfare.

"FLYING DUTCHMAN," a spectre-ship popularly believed to haunt the waters around the Cape of Good Hope. The legend has several variants, but the commonest is that which declares that the captain of the vessel, Vanderdecken, was condemned for his blasphemy to sail round the cape for ever, unable to "make" a port. In the Dutch version the skipper is the ghost of the Dutch seaman Van Straaten. The appearance of the "Flying Dutchman" is considered by sailors as ominous of disaster. The German legend makes one Herr Von Falkenberg the hero, and alleges that he is condemned to sail for ever around the North Sea, on a ship without helm or steersman, playing at dice for his soul with the devil. Sir Walter Scott says the "Flying Dutchman" was originally a vessel laden with bullion. A murder was committed on board, and thereafter the plague broke out among the crew, which closed all ports to the ill-fated craft. The legend has been used by Wagner in his opera _Der fliegende Hollander_.

FLYING-FISH, the name given to two different kinds of fish. The one (_Dactylopterus_) belongs to the gurnard family (_Triglidae_), and is more properly called flying gurnard; the other (_Exocoetus_) has been called flying herring, though more nearly allied to the gar-pike than to the herring. Some other fishes with long pectoral fins (_Pterois_) have been stated to be able to fly, but this has been proved to be incorrect.

The flying gurnards are much less numerous than the _Exocoeti_ with regard to individuals as well as species, there being only three or four species known of the former, whilst more than fifty have been described of the latter, which, besides, are found in numerous shoals of thousands. The _Dactylopteri_ may be readily distinguished by a large bony head armed with spines, hard keeled scales, two dorsal fins, &c. The _Exocoeti_ have thin, deciduous scales, only one dorsal fin, and the ventrals placed far backwards, below the middle of the body; some have long barbels at the chin. In both kinds the pectoral fins are greatly prolonged and enlarged, modified into an organ of flight, and in many species of _Exocoetus_ the ventral fins are similarly enlarged, and evidently assist in the aerial evolutions of these fishes. Flying-fishes are found in the tropical and sub-tropical seas only, and it is a singular fact that the geographical distribution of the two kinds is nearly identical. Flying-fish are more frequently observed in rough weather and in a disturbed sea than during calms; they dart out of the water when pursued by their enemies or frightened by an approaching vessel, but frequently also without any apparent cause, as is also observed in many other fishes; and they rise without regard to the direction of the wind or waves. The fins are kept quietly distended, without any motion, except an occasional vibration caused by the air whenever the surface of the wing is parallel with the current of the wind. Their flight is rapid, greatly exceeding that of a ship going 10 m. an hour, but gradually decreasing in velocity and not extending beyond a distance of 500 ft. Generally it is longer when the fishes fly against, than with or at an angle to, the wind. Any vertical or horizontal deviation from a straight line is not caused at the will of the fish, but by currents of the air; thus they retain a horizontally straight course when flying with or against the wind, but are carried towards the right or left whenever the direction of the wind is at an angle with that of their flight. However, it sometimes happens that the fish during its flight immerses its caudal fin in the water, and by a stroke of its tail turns towards the right or left. In a calm the line of their flight is always also vertically straight or rather parabolic, like the course of a projectile, but it may become undulated in a rough sea, when they are flying against the course of the waves; they then frequently overtop each wave, being carried over it by the pressure of the disturbed air. Flying-fish often fall on board of vessels, but this never happens during a calm or from the lee side, but during a breeze only and from the weather side. In day time they avoid a ship, flying away from it, but during the night when they are unable to see, they frequently fly against the weather board, where they are caught by the current of the air, and carried upwards to a height of 20 ft. above the surface of the water, whilst under ordinary circumstances they keep close to it. All these observations point clearly to the fact that any deflection from a straight course is due to external circumstances, and not to voluntary action on the part of the fish.

A little Malacopterygian fish about 4 in. long has recently been discovered in West Africa which has the habits of a fresh-water flying-fish. It has been named _Pantodon buchholzi_. It has very large pectoral fins with a remarkable muscular process attached to the inner ray. It lives in fresh-water lakes and rivers in the Congo region, and has been caught in its flight above the water in a butterfly-net.

FLYING-FOX, or, more correctly, FOX-BAT. The first name is applied by Europeans in India to the fruit-eating bats of the genus _Pteropus_, which contains more than half the family (_Pteropidae_). This genus is confined to the tropical regions of the Eastern hemisphere and Australia. It comprises numerous species, a considerable proportion of which occur in the islands of the Malay Archipelago. The flying-foxes are the largest of the bats, the kalong of Java (_Pteropus edulis_) measuring about a foot in length, and having an expanse of wing-membrane measuring 5 ft. across. Flying-foxes are gregarious, nocturnal bats, suspending themselves during the day head-downwards by thousands from the branches of trees, where with their wings gathered about them, they bear some resemblance to huge shrivelled-up leaves or to clusters of some peculiar fruit. In Batchian, according to Wallace, they suspend themselves chiefly from the branches of dead trees, where they are easily caught or knocked down by sticks, the natives carrying them home in basketfuls. They are then cooked with abundance of spices, and "are really very good eating, something like hare." Towards evening these bats bestir themselves, and fly off in companies to the village plantations, where they feed on all kinds of fruit, and so numerous and voracious are they that no garden crop has much chance of being gathered which is not specially protected from their attacks. The flying-fox of India (_Pteropus medius_) is a smaller species, but is found in great numbers wherever fruit is to be had in the Indian peninsula.

FLYING-SQUIRREL, properly the name of such members of the squirrel-group of rodent mammals as have a parachute-like expansion of the skin of the flanks, with attachments to the limbs, by means of which they are able to take long flying-leaps from tree to tree. The parachute is supported by a cartilage attached to the wrist or carpus; in addition to the lateral membrane, there is a narrow one from the cheek along the front of each shoulder to the wrist, and in the larger species a third (interfemoral) connecting the hind-limbs with the base of the long tail. Of the two widely distributed genera, _Pteromys_ includes the larger and _Sciuropterus_ the smaller species. The two differ in certain details of dentition, and in the greater development in the former of the parachute, especially the interfemoral portion, which in the latter is almost absent. In _Pteromys_ the tail is cylindrical and comparatively thin, while in _Sciuropterus_ it is broad, flat and laterally expanded, so as to compensate for the absence of the interfemoral membrane by acting as a supplementary parachute.

In general appearance flying-squirrels resemble ordinary squirrels, although they are even more beautifully coloured. Their habits, food, &c., are also very similar to those of the true squirrels, except that they are more nocturnal, and are therefore less often seen. The Indian flying-squirrel (_P. oral_) leaps with its parachute extended from the higher branches of a tree, and descends first directly and then more and more obliquely, until the flight, gradually becoming slower, assumes a horizontal direction, and finally terminates in an ascent to the branch or trunk of the tree to which it was directed. The presence of these rodents at night is made known by their screaming cries. _Sciuropterus_ is represented by _S. velucella_ in eastern Europe and northern Asia, and by a second species in North America, but the other species of this genus and all those of _Pteromys_ are Indo-Malayan. A third genus, _Eupetaurus_, typified by a very large, long-haired, dark-grey species from the mountains to the north-west of Kashmir (_Eu. cinereus_), differs from all other members of the squirrel-family by its tall-crowned molar teeth. It has a total length of 37 in., of which 22 are taken up by the tail.

In Africa the name of flying-squirrel is applied to the members of a very different family of rodents, the _Anomaluridae_, which are provided with a parachute. Since, however, this parachute is absent in some members of the family, the most distinctive character is the presence of a double row of spiny scales on the under surface of the tail, which apparently aid in climbing. The flying species are also distinguished from ordinary flying-squirrels by the circumstance that the additional bone serving for the support of the fore part of the flying-membrane rises from the elbow-joint instead of from the wrist. The family is represented by two flying genera, _Anomalurus_ and _Idiurus_; the latter containing only one very minute species (shown in the cut) characterized by its small ears and elongated tail. Most of the species are West African. In habits these rodents appear to be very similar to the true flying-squirrels. The species without a parachute constitutes the genus _Zenkerella_, and looks very like an ordinary squirrel (see RODENTIA).