or irritation experienced in temperate regions from fly-larvæ, gnats, midges, &c., and the parasitic species, are aggravated in both warmer and more boreal countries to a dangerous extent, and have even been found prejudicial to life. There are many recorded instances of the larvae of Diptera feeding upon the human intestinal canal, and of species (dubiously referred to Œstrus) attacking man; as also of loathsome cases of individuals being eaten alive by the larvae of flies, developed in food secreted about the persons of beggars. Various cases have, moreover, recently been noted of the diffusion of the germs of disease by flies; and instances of death from transference of putrid animal matter in New Caledonia have also been recorded. One of the Muscidæ, Lucilia hominivorax, is known to have caused considerable destruction to human life among French convicts in Cayenne, laying its eggs in the mouth or nostrils during sleep ; and a very precise account of much disease and death in man and domestic animals at Mohilew, by a similar action of another of the same family, Sarcophila wohlfarti, has recently been given by Portchinsky, a Russian naturalist. It is perhaps super fluous to speak of mosquitoes, too well known since the Biblical " plague of flies ; " but it may be observed that the corresponding plague of sand-flies, Simulium, so well known to affect the eyes of sufferers from ophthalmia in Egypt, has made its appearance in the deserts of West
Australia, where the last exploring expedition of Mr Ernest Giles suffered severely from it.The antiquity of the fly is scarcely more than historical. Very few fossil species are known (5 only being recorded from the Solenhofen lithographic Oolite) ; but the more recent " flies in amber " are so constantly found that the expression has become a common proverb.
DIPTYCH, a double tablet made with a hinge to open and shut. Diptychs were used in the time of the Roman empire for sending letters—“mainly love letters,” says Facciolati, quoting the scholiast to Juvenal ix. 36, whose note does not, however, seem to imply as much. The consuls and quæstors used, on assuming office, to send diptychs containing their names and portraits to their friends. The exterior of the leaves was often ornamented with other paintings. The tablets were made, the more ordinary kind of boxwood or maple, the richer sort of cedar, of ivory, of silver, and sometimes even of gold. They were very frequently sent by friends to each other as presents at the beginning of a new year. The early Christians used tablets thus made in the celebration of divine worship. And Cardinal Noris (Dissertat. de Hist. Synod.) expends much learning in showing, what is very evident, that the Christians adopted the use of them from that of the consular diptychs. They were placed on the “ambones,”—the pulpits, or reading desks, which may still be seen in ancient basilicas at the west end of the choir or presbytery ; and from them were read to the congregation of the faithful the names of the celebrating priests, of those who occupied the superior positions in the Christian hierarchy, of the saints, martyrs, and confessors, and, in process of time, also of those who had died in the faith. It is the diptychs that are referred to by the early Christian writers under the names of " mystic tablets," " anniversary books," " matriculation registers " of the church, and some times " books of the living," or " books of life." The word is also occasionally found used in other senses, e.g. for the priest's vestment, which was usually folded in two (see Ducange, ad voc.) When it became customary to write iu the diptychs names so numerous as those of the different classes of persons above mentioned, it will be easily under stood that it became impossible to inscribe them on two tablets of convenient size. Hence the diptychs became triptychs, i.e., consisting of three such conjoined tablets. But, though triptychs are often spoken of in the art-language of a later time, these were by the early church writers still called diptychs; and continued to be so called, even when many leaves, probably of parchment in some cases, though mors frequently of wood, were introduced between the two original folds of the diptych, thus forming a veritable book. The inscription on the diptychs of deaths and baptisms, naturally led to the insertion of dates, and the diptychs seem thus to have grown into calendars, and to have been the germ from which necrologies, lists of saints, and almanacs have been developed. Much doubt exists as to the time when the use of diptychs to read from died out in the church. The best opinion seems to be that their use lasted to about the end of the 8th century. The outsides of the diptych folds being often very richly ornamented, their preservation was carefully attended to, and even those which were ornamented with profane paintings or carvings were often to be found in use in tho primitive churches. This ornamentation caused the diptychs to be exhibited to the congregation, and used as adornments for the altar. And in this position, by a natural process of development, the ornamentation became the main end and object of the thing itself. The best painters of the time employed their talents in painting them—generally in the form of triptychs, and on both sides of the folding doors, so that the triptych when closed showed two subjects, often the portraits of the donor and his wife, and when open three paintings;—hence the very large number of diptychs and triptychs which are found in our museums and galleries.
See Bingham, Orig. Eccles., lib. xv. ch. 13, sec. 18, and Moroni, Erudizione Storica-Ecclcsiastica.
DIRCE, in Greek legend, the personification of a fountain (and stream) at Thebes, from the water of which Hercules derived part of his strength, and which was usually identified with the fountain of Ares in the legend of Cadmus. Besides, the fountain was the grave of Dirce, at which sacrifices for the dead and other rites were performed. According to the legend, Dirce, the wife of Lycus, king of Thebes, had sorely persecuted Antiope, who at last escaped to Mount Cithaaron, where her twin sons Amphion and Zethus were being brought up by a herdsman unconscious of their parentage. Mother and sons met, but had not recognized each other, till Dirce, who had come to the hill for a Dionysiac ceremony, proposed that Amphion and Zethus should tie Antiope to the horns of a wild bull to be dragged to death. They were about to do this when the herdsman announced their relationship, and they then tied Dirce to the bull instead. She was dragged by it over the hill to the fountain into which she was transformed.
DIRSCHAU, in Polish Szczewo, a town of Prussia, in the government of Dantzic and district of Stargard, on the left bank of the Vistula, at a railway junction about twenty miles S.S.E. of Dantzic. Besides dealing in wood and cattle, it displays considerable industrial activity in the manufacture of agricultural implements, iron and tin wares, and cement ; but its principal claim to attention is the lattice-work iron bridge, thrown across the river in 1850–1857, which, with its total length of 2726 feet and its six spans of 410 feet each, is a noble testimony to the engineering skill of Lentze and Schinz, and affords a passage for the railway between Königsberg and Berlin, for two ordinary carriage roads, and two sideways for foot passengers. Unfortunately, as it lies only about 12 feet above the highest level attained by the river, and there is no opening for the passage of ships, it is necessary in passing under it to remove or drop the masts. J. Forster, the traveller, was born at Dirschau in 1729. Population in 1875, 9727.
