Page:Encyclopædia Britannica, Ninth Edition, v. 12.djvu/329

Rh HOUSE-FLY. Although extremely abundant in individual representatives, by habit specially attached to mankind, of widely extended range (North American and Abyssinian exponents are absolutely identical with European), familiar from the earliest times, engrafted upon the literature of all nations by proverbial and poetical allusions, and of later affording material for much scientific microscopical investigation, the dipterous species known to naturalists as Musca domestica apparently has two pecu liarities opposed to these premises: one, that its lack of salient external features would puzzle any but a profound dipterologist to define its specific attributes with absolute certainty; the other, that its earlier life history and trans formations remained practically unknown (at all events to orditiary readers) up to 1873. It is scarcely within the province of this work to diagnose species; the instincts of the majority of readers will probably direct them at once to the right insect, which may be roughly described as a quarter of an long, black, hairy, with a reddish oval vertical spot and golden orbits, three grey longitudinal bands on the thorax, an interrupted yellowish band at the base of the abdomen, which has lateral and apical golden spots, and the base of the wings yellowish-white. But not only allied species are liable to be confused with the house-fly; representatives of other genera, such as Anthomyia, Tachina, and Stomoxys, are often mistaken for it, and a puncture from the sharp beak of the latter fly has often caused a wrong charge of blood-sucking to be brought against the subject of this notice, which has a short fleshy bilobed tongue incapable of penetrating the skin, though provided with a terminal framework of tracheal tubes, acting like a rasp, by using which it often annoys us in the heat of summer. As regards the second point, Linnueus, who first named the fly, left its transformations undescribed; De Geer in 1776, and Bouch in 1834, described the larva and pupa, and correctly defined their habitat; but it has been reserved for DrA. S. Packard, jun., the well-known American entomologist and biologist, to make a thorough investigation of their whole economy, which he has published in the Proceedings of the Boston Society of Natural History, vol. xvi. (for 1873-74), pp. 136-150, pi. iii.

1em 1em 1em 1em  HOUSELEEK, Semper vivum, a genus of ornamental evergreen plants belonging to the natural order Crassulacece. About 30 species are known in gardens, some of which are hardy perennial herbs, and grow well in dry or rocky situations; the others are evergreen shrubs or under-shrubs, fit only for cultivation in the greenhouse or con servatory. The genus tiempervivum is distinguished from the nearly allied Sedum by having about 12 petals, and by the glands at the base of the ovary being laciniated if present. The common houseleek, S. tectorum, L. (Germ. Hausivarzel; Fr. Joularbe), is often met with in Britain on roofs of outhouses and wall tops, but is not a native. Originally it was indigenous in the Alps, but it is now widely dispersed in Europe, and has been introduced into America. The leaves are thick, fleshy, and succu lent, and are arranged in the form of a rosette lying close to the soil. The plant propagates itself by offsets on all sides, so that it forms after a time a dense cushion or aggregation of rosettes. The flowering stem, which is of rather rare occurrence, is about a foot high, reddish, cylindrical, and succulent, and terminates in a level-topped cyme, reflexed at the circumference, of reddish flowers, which bloom from June to September. The houseleek has been known variously as the Houselick, Homewort, Great Houseleek, Sedum ma jus, and Crassida major altera, Sedum acre, L., being styled the Least Houseleek. In Germany it is sometimes called Donnerkraut, from being supposed to protect the house on which it grows from thunder. The leaves are said to contain malic acid in considerable quantity, and are reckoned by herbalists to possess cooling and astringent properties. The leaves, freshly bruised, are applied to haemorrhoids, boils, wens, and corns, and the expressed juice is used as a remedy for inflammation of the eyes and freckles, and especially for thrush (aphtha:) in children, also for stings and burns, ery sipelas and herpes. Internally houseleek is used as a cooling remedy in dysentery and fluxes. The young leaves have also been eaten as salad, like Portufacca. . ghitinosum, Ait., and S. balsamiferum, Webb, natives respectively of Madeira and the Canary Islands, contain a very viscous sub stance in large quantity, and are used for the preparation of bird-lime; fishermen in Madeira, after clipping their nets in an alkaline solution, rub them with this substance, render ing them as tough as leather. S. montanum, L., indigenous in Central Europe, according to Gmelin, causes violent purging; S. arboreiim, L., TO fj-tya. uei^coov of Dioscorides, is employed in Cyprus, the East, and northern Africa as 