DION^A 369 DIOSCOREACE^ las rendered him one of the most dis- tinguished heroes. He wounded Aphro- dite and Ares, and thrice assailed Apollo; and by carrying off the horses of Rhoesus from the enemies' tents, and aid- ing Ulysses in the removal of Philoctetes from Lemnos, he fulfilled two of the con- ditions on which alone Troy could be con- quered. Finally he was one of the heroes concealed in the wooden horse by whom the capture of Troy was at length ac- complished. Different accounts were given of his after-life. He is often called Diomede. DIOGENES DION.aiA (Gr. Dione, one of the names of Venus), a genus of plants belonging to the natural order Droseracese. It consists of a single species, D. muscipida, commonly called Venus' fly-trap. The lamina is articulated to the pedicle, and consists of two portions united together by a joint along the midrib. On the upper side of each part of the lamina are situ- ated three irritable hairs, which, on being touched, cause the folding of the divisions from below upward, so as to inclose any object. The food thus captured is di- gested by the action of a fluid resembling gastric juice. Venus' fly-trap is a native of the United States. DIONYSIUS, a historian and critic of Plalicamassus, in Caria, who was invited to Rome about 30 B. c, and there wrote his "Roman Antiquities." Other works are "De Compositione Verborum," and the "Structure of Language." Lived in the 1st century, dying about 7 B. c. DIONYSIUS I., the Elder, tryant of Syracuse; was born 430 B. c. He served in the war with the Carthaginians, got himself appointed general, and, in 405, sole emperor and head of the republic. He formed a powerful bodyguard, con- quered other cities of Sicily, carried on war with the Carthaginians, and after making peace with them in 392, invaded Italy and subdued several of the Greek cities of the south. He was afterward again at war with Carthage. Dionysius, like some other tyrants, was a patron of literary men and artists, aspired to literary fame, and contended for the prize at the Olympic games. He erected many fine temples. He died in 367. DIONYSIUS II., the Younger, tyrant of Syracuse, was son of the preceding, and succeeded him, 367 B. c. Idly brought up, he was for a time restrained from excesses by the influence of Dion and Plato. His subsequent treatment of Dion and his family led to his own over- throw in 356. He went to Italy and ob- tained the chief power at Locri, and after 10 years' absence returned and re- gained his throne at Syracuse. A final end was put to his tyi'anny by the noble Greek Timoleon, 343, and he spent the rest of his life in exile at Corinth. DIONYSUS, or DIONYSOS (di-5-nr sus), the Greek god of wine, son of Zeus and Semele. Zeus appearing to Semele in thunder and lightning so affrighted her as to cause the premature birth of Dionysus. Zeus carried the babe in his thigh, and when it came to maturity placed it in Ino's care. Dionysus wan- dered over the world teaching the culti- vation of the vine. One of his surnames was Bacchus. DIOPTRICS, that branch of geometri- cal optics which treats of the transmis- sion of rays of light from one medium into another differing in kind. It con- sists of the results of the application of geometry to ascertam in particular cases the action of what are called the laws of refraction. DIORITE, a granite-like rock, con- sisting of hornblende and albite. It is grayish-white to nearly black in color. It derives its name from being unmistak- ably or clearly defined, as distinguished from dolerite. DIOSCOREACE^, a natural order of plants belonging to the class Dictyogcns, consisting of twining shrubs. Lindley enumerates six genera and 110 species, Testudinaria Elephantipes is the tortoise
