CHAIiCEDONY. 459 CHAI.CIS FLIES. or filling of cavities in rocks. The principal va- rieties of chalcedony are ayatc, which is banded and striped; canicUaii, which is clear and of various shades of red; chnisoi>rasc, an apple- green variety, in which the ct)lor is due to nickel o.xide : hcliotroi.r vr bloodslonc, of a dark {^rceu color, with small spots of jasper; onyx, con- sisting of bands of dilTcrcnt colors, usually black and white: plasma, of a deep frrcen color; and sardoiii/x, a red ban<led variety of onyx, all of which are described in special articles under their names. The variety of its colors and th(> ■high luster that it takes by polishing, render chalcedony valuable for brooches, necklaces, and other ornaments, and some varieties of it are cut qs seal-stones. Chalcedony is found in Great Britain, in Brazil, and in a numl)er of localities in Colorado and California. The formation of the famous agatized wood of Chalcedony Park, Ariz., is caused by a natural replacement of the woody fibre by chaUedouy from siliceous waters. CHALCEDOirrX, kril-sed'o-niks (from Gk. X(Ojii]6uv, (.halkCdOii, chalcedony + o«f, onyx, finger-nail. onyx. Lat. onyx. See Chalcedony). A variety of agate consisting of alternate layers of a wliite opaque and a grayish translucent chalcedony. CHALCHIHUITL, chal'che-we'fl (IMexi- can). A green mineral referred to by Spanish writers contemporary with Cortes. It was held in high repute by the ancient Mexicans, who val- ued it more than gold. The Mexicans believed that the art of cutting and polishing chalchihuitl had been taught them by the god t^)uetzaleohuatl. The best authorities believe the mineral to have been the bluish-green ariety of turquoise from Los Cerillos mines, New Mexico, although some still think it is a variety of jadeite. CHAXCIDICE, kal-sid'I-se (Lat.. from Gk. XaKi5uc-^, sc. xi^po, chOiu. district. Chalkidikc, of Chakis). The ancient name of three districts in Grecian or partly (Jreeian lands. (1) In Eu- boea, the land belonging to the inhabitants of the town of Chalcis. on the southwestern side of the island, near the Strait of Euripus. (2) A district of Macedonia, between the Thermaic and Strynionic gulfs. Tlic lower part of this dis- trict forms three |)eninsulas, called, from west to east, Pallene (or. more anciently. Phlegra), Sithonia. and Acte or Athos. This district re- ceived its name from Chalcis, in Eubeea. having been settled in the Eighth Century B.C. by colo- nists from that place. Among the flourishing towns of Chalcidice were Olynthus and Potida-a. (3) A district in Syria, extending eastward from the Orontes River to the desert, and called Chalcidice from the town of Chalcis, lying there- in. CHAX.CIS, kal'sis (Lat., from Gk. XaJ/c/f, Challcis) . The capital of the island and no- marchy of Eubcea, (ireece, situated on the Euri- pus, the strait which separates the island from HiEotia (Map: Greece, E .3). The Euripiis is divided into two channels, of unequal breadth and depth, by a rock, which is surmounted by a castle, partly of Venetian and partly of Turk- ish construction. A shallow channel, 8.5 feet wide, .separates the rock from Bceotia, and is crossed by a stone bridge. The main channel, about 120 feet wide, through which a strong current fiows, was at one time crossed by a drawbridge, which has recently been removed in Vol. IV.— 30. connection with operations for widening and deepening the channel. The site seems to have been o<vu])icd in very early times, and during the Xintli and Eighth centuries n.c. the inhabit- ants were active colonizers, specially toward the north, where they gave their name to the Chal- cidian peninsula on the Macedonian coast. They also appear early as allies of the Corinthians in the Greek colonization of Italy and Sicily, where they settled Cuma' and Xaxos. and gave their alphabet to the Italians. After a long war with its rival, Eretria, Chalcis acquired the undisputed hcad.ship of Kuboea, and rapidly rose to wealth and importance. Its govern- ment was strongly aristocratic, but after a crushing defeat at the hands of the Athenians (B.C. 500), the nobles were driven out and a democracy established. It subsequently fell un- der the power of the Macedonians and Romans, and was at this time a place of great military importance, nearly nine miles in circmnfcrenee, and had many fine temples, theatres, and other pulilie buildings. Aristotle died at Chalcis. In the iliddle Ages, it was prosperous under the Venetians, who held it for nearly three centu- ries, until its conquest by the Turks in 1470. Not many ancient remains now exist at Chalcis. The streets are narrow, but the houses, many of which owe their origin to the Venetians, arc sub- stantial and spacious. It suffered from an earthquake in 189-1. Population about 9900. CHALCIS (kal'sis) FLIES, or CHALCID- ID.S), kal-sid'i-de (Xeo-Lat. nom pL, from tJk. Xa^MC, chalkis, lizard, either from XaXicis, Clialkis, a city of Euba?a, or, more probably, like the name of the town itself, from ro/'i-'if, chalkos, copper). A group of very small Hymenoptcra. characterized by elbowed feelers. They number thousands of species, and arc truly parasitic, ex- cept a few gall-making genera. One large sec- tion glues its eggs upon the backs of caterpillars of moths. These eggs hatch in about two days, when the grubs quickly bury their heads in the skin of their host and begin to feed, growing more rapidly than any other known insect-larvoe, and reaching full growth within three or four days. The first to mature then withdraws its head, preparatory to pupating — an act which at once causes the death of the ex- hausted caterpillar and consequently of ni any belated grubs. The more advanced survivors spin and attach their cocoon to the under side of the empty skin of the dead host, which thus furnishes a roof, and within about eight days complete their transformation and emerge as adult chalceids. The fact that they attack ni.any fly-maggots, caterpillars, etc.. greatly injurious" to" cultivated plants, and de- stroy them with much sjiecd and certainty, places them among the most valuable aids man- kind has in his warfare -against insect pests. It is due to these insects, ))rincipally, that the cotton-worm of the South is kept down, and millions of dollars' worth of cotton saved each vcar. "Xowhere in Xature." remarks L. O. CHAIX;I3 FLY.
