G N A
G N A
■ftpon occafion cover this light (a as hot to be known, Or purfued by it, by its enemies. Thomas Barthol. de Luce Anim. Lib. 2. Cap. 12.
This infect is of the beetle kind, of a brown and dufky colour. It has hard cafe or fhell wings as the other beetles have, and when thefe are expanded, there appear a pair of very large membranous ones ; its head is covered with a fort of fhield or broad brim'd hat ; under this hat are placed the eyes, which are black and large, and are moveable ; fo that the creature can upon occafion thruft them forward to the fides of the hat, or covering of the head ; it has two hairy antennas, and its legs are like thofe of the common fly, hard, fhelly, and hairy. Its eyes afford an elegant object for the microfcope, being compofed of an infinite number of lenfes, as thofe of the libella: and other infects. Aldro- iiand. de Infect. Lib. 1. Cap. B\
CLUE (Cycl.) — A ftrong and fine glue may be prepared with ifmglafs and fpirit of wine, thus ; fteep the ifinglafs for twenty four hours in fpirit of wine or common brandy. When the menftruum has opened and mollified the ifin- glafs, they muft be gently boiled together, and kept ftirring till they appear well mixed, and till a drop thereof fuffered to cool, prefently turns to a ftrong jelly. Then ftrain it while hot through a clean linnen cloth, into a veftel to be kept clofe flopped. A gentle heat fuffices to diflblve this glue into a tranfparcnt and almoft colourlefs fluid, but very ftrong; fo that pieces of wood glued together with it, will feparate elfewhere, than in the parts joined. Boyle's works, Abridg. Vol. 1. p. 130.
GLUME, gluma, among botanifts, a fpecies of cup confifting of two or three membranous valves, which are often pellu- cid at their edges. This kind of cup belongs to the grades. See the article Grass.
GLUTTA, a name given by fome authors to the gutta gamba, or gamboge. See Gamboge.
GLYCOPICROS, in botany, a name by which fome authors have called the folanum lignofum, or dulcamara. J. Bauhin. Vol. 2. p. 109.
GLYCYCALAMUS, a word ufed fingly as the name of a vegetable fubftancc, by fome of the Greek writers ; but by the moft antient, it is only ufed as an epithet for a peculiar kind of lotus. This lotus glycycalamus, is a name given by Myrepfus and others to the caffia fiftula, but by other of the antients, it feems to have been made the name of the fugar cane. See Lotus.
GLYCYNE, in botany, the name given by Linnaeus to a genus of plants, fome of the fpecies of which are defcribed by Boerhaave under the name of apios, the characters are thefe. The cup is a one leaved comprefied perianthium, divided at the extremity into two lips, the upper of which is emar- ginated and obtufe, the under one is long, obtufe, and di- vided into three fegments, the intermediate one of which is longer than the others. The corolla is of the papilionace- ous kind. The vexillum is obtufely cordated, the fides are bent back, and the back gibbous, the end ftrait and margi- nated. The &\te are oblong, oval toward the end, fmall and bent downwards. The carina is {lender, falcated, and bent upwards, and is broadeft toward the apex, where it rifes up to the vexillum. The filaments are diadelphous, and the apices fimple. The germen of the pift il is oblong. The ftyle is cylindric, and twifted into a fpiral form, and the ftigma is obtufe. The fruit is an oblong bilocular pod. The feeds are kidney fhaped. Linntsi Gen. PI. 370. Boerhaave Ind. ult. 14.6.
GLYCYRRHIZA, liquorice, in botany, the name of a genus of plants, the characters of which are thefe. The flower is of the papilionaceous kind, and from its cup there arifes a piftil, which finally becomes a fhort pod, which ufually contains a number of kidney fhaped feeds. To this it may he added, that the leaves are placed oppofite to one another, manv of them on a long middle rib which has a fingle one to termi- nate it at the end.
The fpecies of glycyrrhiza mentioned by Mr. Tournefort are two. 1. The glycyrrhiza or liquorice with echinated heads, and 2. the german or podded liquorice. SeeLiquoRiCE.
GNAPHALIUM, cudweed, in botany, the name of a genus of plants, the characters of which are thefe. The flower is of the flofculous kind, being compofed of many fmall flof- cules, ftanding on the embryo feeds, each divided into fe- veral fegments at the end, and among thefe are intermixed many imbricated leaves, all comprehended in a general cup of a foliacious ftructure and hemifpheric figure. The em- bryos become hard feeds covered with a fort of hood. There is only one known fpecies of this genus, which is the plant commonly called Gnaphalium maritimum, the fea cudweed. Toum. Inft. p. 461.
The common cudweed is deficcative and aftringent, and is of great efficacy in hemorrhages of all kinds. In dyfenteries, and in floodings of the menfes, it has been known to do great cures. Some have recommended the diftilled water of it m cancers, but this feems to have no very great founda- tion. A decoction of it in fmall beer is a common medi- cine among country people for quinfies, and is faid fome-. times to have done remarkable cures in them.
GNAPHALOIDES, in botany, the name of a genus of plants, the characters of which are thefe. The flower is of the flofculous kind, being compofed of a number of fmall flof- cules which are barren. The embryo feeds conftitute the cup of the flower, which afterwards becomes a crefted fruit containing ufually an oblong feed.
There is only one known fpecies of this plant, which is called by fome, the fmall procumbent cudweed from Portu- gal with echinated feed. Toum. Inft. p. 439.
GNAPHEUS, in ichthyology, a name given by Athe- nxus and other of the Greek writers to the tench. See the articles TiNCAand Cyprinus.
GNATS. There is no fpecies of infect that we have fo much reafon to diflike in regard to the injury it does us as the gnat. Others indeed give us more pain with their ftings, but 'tis but by accident that we are ftruck by them ; the gnats thirft for our blood, and follow us about in whole compa- nies for it. There are many marfhy places where the legs and arms are all the fummer fwelled to an enormous fize by the repeated bitings of thefe infects, and in many other countries they are yet greatly more troublefome than with us. Reaumur Hift. Inf. Vol. 4. p. 574. But as troublefome enemies as thefe little creatures are to us, there is that about them which is extremely worthy our admiration, nor can we indeed fail greatly to admire even the very inftrument of the mifchief they do. They have befide this many very obfervable particulars in the courfe of their lives, and there is one moment of that in which forgetting the trouble they are likely to give us we cannot but be felicitous for their fafety. All the naturaliffs of late years have applied the microfcope to the examination of the parts of this little animal, and Swammerdam, Hook, Bonanni, Lewenhoek, &c. have given very good accounts, and very valuable drawings of the creature.
The external figure of the gnat is well known, yet not enough to prevent fome miftakes about it, as it is frequently confounded with the tipula, or father long legs as we vulgarly call it in England, There are many marks indeed which they have in common, they both have fuch long legs, that they look as if mounted upon ftilts. Both have long {lender bodies, and both prominent corcelets, which make them look hump backed ; but when either of thefe infects is taken into the hand it is very eafily known, the gnat having a very long trunk, and the tipula no trunk at all. There is a great number of very fmall fpecies of gnats, and though fome are confiderably large, yet none even of thefe approaches to the fize of the tipula. The larger tipulse are therefore eafily diftinguifhed from the gnats, but Swam- merdam, Gocdart, Lifter, and others have very often given us the fmaller tipulas among the fpecies of gnats. There is a prodigious number of fpecies of the gnat kind taking in the fmaller ones, but of thofe of a fize to be re- marked with eafe, and without the help of glafTes, there are three principal kinds ; the one has its body variegated with white and black ; this is the larger kind, and its corcelet is ftreaked with black or deep brown, and white lines or grey- ifh ones ; thefe have brown eyes. Another is fmaller than this fpecies, and has a plain brown body, the colour of the corcelet, and that of the eyes is the fame as in the larger or firft fpecies. The third kind is the fmaHeft of the three and the moft common, has its corcelet reddifh, or of a faded reddifh yellow, and the body whitifh, and on the under part of the belly, every ring has one fingle brown fpot ; the reft is grey. The eyes of this fpecies are of a very pleafant green.
All the gnats have a long cylindric body compofed of eight rings j their corcelet is fhort, but large in proportion to the fize of the fly, and to this are fixed the leg, the wings, and the balancers ; four fKgmata are alfo found here as is the cafe in other flies. The two firft of thefe are placed near the head, and have been miftaken for ears. When the gnat is in a ftate of reft, it holds one wingfome- whatcrofiedover the other, in fuch a manner, as that they cover the body. It has a multitude of little oblong fcales on its wings, and not only there, but on its corcelet and body ; and they are fo thick laid on the body, that one cannot touch it with- out rubbing them off, and leaving the part naked. Eeftde thefe, they have alfo very long and extremely fine hairs, and fome of the fpecies have ranges of thefe on each fide the body appearing like fringes. The antennre of ihegnats are extremely worth obfervation, and differ much from one another. Some of them are elegantly feathered, thefe be- long to the males of certain fpecies, for the antennae of the females are not fo beautiful.
Thefe feathered antennae of the male gnats, examined by the microfcope, fhew at every junction of two of the rings, a fmall clufter of hairs in form of a pencil on each fide ; the hairs of which thefe are compofed feparate, and fpread toward their extremities ; thefe cktfters of them grow fhorter as they ap- proach the upper part of the antenna?, and toward the extremity of each, there is a vacant fpace where they are wholly wanting ; this part however is covered with fingle fhort hairs.
The
