SWALLOW. 734 SWAMMEBDAM. ally forked, and the plumage is close and glossy. The family is perhajjs the most sharply defined and easily recognized of any in the order. The species are about eighty, widely diffused, being found in all countries except near the poles. Such of them as occur in the colder parts of the world are summer birds of passage, migrating to Tvarmer regions when winter approaches and in- sects become scarce. Only seven species of swal- low occur in North America, and all but one of these winter south of the United States, though in summer they range to the Arctic Ocean. The largest species is the purple martin, while the smallest is the bank swallow (q.v. ) . Perhaps the connnonest of North American swallows is the barn-swallow (q.v.). Another swallow nu- merous about farmyards and barns is the cliff or eaves swallow {Petroehclidon hinifrons), whose nest is the remarkable flask-shaped structure of pellets of mud often seen attached in rows to the outside walls of barns, just under the eaves. Formerly, as in the case of other swallows (see Barx-Swallow) , this species bred in rocky places and placed its nests in large companies against the faces of cliffs. A large and handsome swallow common throughout North America is the white-bellied or tree swallow (Tacltycineta bicolor) , which is steel blue or green above and pure white beneath. Of the same genus is the exquisite little violet- green swallow {Tachj/cineta thallasina) of the Western United States, which is less than five inches long; the upper parts are velvety green and violet purple, while the under parts are pure white. The rough -winged swallow (q.v.) com- pletes the list. South America has a large series of swallows very similar to those of the United States, and es])eciall.y of that group of which the tree and violet-green swallows are a type. Some naturally breed in holes of rocks, others in hollow trees, or form nests of )nud, straw, and feathers in some similar situation; but nearly all have abandoned their wild ways as fast as the country has been settled, and placed their abodes near or within buildings. The same pleasing habit char- acterizes the tribe in India, Africa, Australia, and everywhere else, and has led to the growth of much pleasant folk-lore, poetry, and senti- ment. In Great Britain Hirinulo rnstica. the common or 'chinmey swallow' (to be distin- guished from the American chimney swift, q.v.), is much like our barn-swallow, and makes a simi- lar nest, usually placed under a shed roof, in a half-ruined building, or often in a chimney. The geographical range of this species extends over a great part of Europe, Asia, and Africa. ■ The window swallow, or house-martin [Eirundo urbica) , is another very common European spe- cies, glossy black above, white below and on the rump; the feet covered with short downiy white feathers, which is not the case in the chimney swallow. Consult Sharpe and Wyatt, Monofjraph of the Hirundinidce (London. 18S5-94), which contains a description, with colored plates, of all the species of the world, and a full bibliography. SWALLOWTAIL. Any member of a family of large butterflies, Papilionidse, with tail-like prolongations of the hind wings. Black, yellow, blue, and green are the prevailing colors. About 25 species occur in the United States, South America is most rich in these butterflies. About 700 sjiecies have been described in all. The larvje of the swallortails possess a curious process on the thorax called an 'osmaterium,' which is usually retracted, but may be thrust forth at will. It is a Y-shaped process and eon- tains a scent-gland which emits a strong odor when the organ is thrust out. The pupa is placed with the head upward, fastened by the tail to the supporting object, and is kept in place by a silk band around the middle of the bod.v. (See But- terflies; also Plate under Butterflie.s, Fig. 5.) In certain species the males and females differ so much both in form and coloration that they might easily be mistaken for distinct species. In New Guinea there occurs a swallow-tail butterfly (Ormthoptera paradisea) the female of which is black, white, and gr.ay, and the male is gold and green, with very long tails on the hind wings. The males of another species of the same genus are numerous and the female is rare; the propor- tion is said to be about 1000 to 15. Not only does the female show sexual dimorphism, but even considerable seasonal dimorphism. The tiger swallowtail (Jnsonktdes glaucus) is a North American species which shows a striking sexual dimorphism in a portion of its range. The form now known as Tiirnus is straw-colored above, banded and marked with black. In the South and West black forms of the female sex occur, and belong to the so-called 'glmicnf' form. Tile caterpillar of these two forms is dark green with two ]uirple eye-spots, one on each side of the third thoracic segment, which are bordered with black, yellow, and black again in turn. When not feeding, this caterpillar rests on a bed of silk spun on a leaf. The zebra swallowtail (1 phi- elides Ajax) presents one of the most striking cases of seasonal dimorphism known among but- terflies, so that until the life-history of this form was known three different species had been de- scribed from it. There are several broods a sea- son and the last brood winters in the chrysalis stage. The butterflies that appear in tlie earl.v spring are known as the AlarceUus form and those that appear later in the spring as the Tela- monidcs form. The latter are larger butterflies with lon.cer tails and more white than the Mar- ccUus form. (See Colored Plate of American Butterflies.) All the late spring broods pro- duce a third form which is still larger and with longer tails. Tliis summer brood is known as the Ajax form. See illustration at Skipper. SWALLOWTHORN, or Sea-Buckthobx (Hippophae). A genus of shrubs of the natural order Elseagnacea:, natives of Europe. The com- monest species (Hippophae rhamnoides) is a spiny shrub often planted for ornament in sandy soil, especially near the sea. It is valued for its silvery leaves and yellow, acid, one-seeded Ijcr- ries, which, besides being attractive, are useful for sauces and jellies. SWAMMEBDAM, swiini'mer-dam, ,Tan (16.37-80). A Dutch naturalist, born in Amstei-- dam. He studied medicine at Leyden. but devoted most of his life to the study of insects and other animals. He was a skilled dissector of small ani- mals, and was the father of the scientific study of the morphology and metamorphosis of insects. He first made a natural classification of insects by distingiiishing between those which have a complete metamorphosis and those which have not. He wrote: De Respiratione ustique Pul- nwniim (1G67); AUgemeene verhandcling van
