G N A 
G N A 
fcalcs and hair, In order to fecure it from the incle- 
mency of the weather; and it makes trial of the ac- 
tivity of it's wings, by rubbing them either againfl: 
it's body, or it's broad fide-bags, which keep it in 
equilibrium. 
But no part of this infeft is more remarkable, or 
of m,ore importance, than it's trunk, v/hich may 
juftly be deemed one of nature's mafter-pieces ; and 
is fo very fmall, that it's extremity can fcarcely be 
difcerned by the affiftance of the befc microfcope 
that can be procured. That part which is at firft 
obvious to the eye, is only a long fcaly fhcath un- 
der the throat: at the diftance of near two-thirds of 
it's length, there is an aperture through which the 
animal darts out four ftings, and afterwards retradts 
them; one of which, however iharp and active it 
may be, is no other than the cafe that conta-ns the 
other three, for whofe reception it is furniilied v/ith 
a long groove. Thefe ftings are fharpened on 
both fides; they are likewife barbed; and have a 
vaft number of cutting-teeth towards their points, 
which are reverted, and fine beyond expreflion. 
When all thefe darts are thruft into the flefli of 
animals, fometimes one after another, and at others 
all at once, the blood and humours of the adja- 
cent parts are unavoidably extravafated ; on which 
tumours enfue, whole Uttie orifices are foon clofed 
up by the compreffion of the external air. 
When the Gnat, by means of the extremity of 
it's cafe, which it ufes inftead ot a tongue, has 
tafted any fruit, flefii, or juice, that it has difco- 
vered; if it be a fluid, it is fucked up without the 
protrufion of the darts; but, in cafe the leaft re- 
iiftance is made by the obftruftion of flelh, or 
other hard fubftances, the infe6l exerts it's ftrength, 
and penetrates it if pofiible with it's weapons. 
This being atchieved, it draws it's ftings into their 
fheath, which is applied to the v;ound, in order 
to extract, as through a reed, the juices which are 
therein inclofed. 
But though the Gnat is very a6tive and trou- 
blefome in the fummer months, during winter it 
ceafes to receive any food; and fpends all that te- 
dious feafon either in quarries or caverns, which, 
at the return of fummer, are abandoned for fome 
commodious ford, or ftagnant water, where it may 
produce it's kind. Indeed, the young brood is 
fometimes fo numerous, that the very water is 
tinged, according to the colour of the fpecies, 
which is very various, and in general very beau- 
tiful. 
Nothing, however, is more curious in the hif- 
tory of this animalcule, than it's method of pro- 
pagation. Though all infedls of the Gnat kind 
are pretty fimilar in their conformation and gene- 
ral appearance, they difi'er v/idely from each other 
in the manner in which they are produced: for 
fome are viviparous, others oviparous; fome are 
males, and unite with the females; others are fe- 
males, requiring tiie impregnation of the males ; 
and fome, though of neither fex, produce young 
v/ithout any copulation or contafl whatever. This 
is indeed one of the greateft irregularities in the 
hiftory of nature; but it is neverthelefs true. A 
Gnat, feparated from the reft of it's kind, and in- 
' clofed in a glafs veflel, with air fufficient to keep 
it alive, will produce young; which alfo, when 
feparated fi-om each other, will be the parents of a 
numerous progeny. Thus, through five or fix 
generations, will thefe extraordinary animals pro- 
pagate without the aid of copulation, and v/ithout 
any congrefs between the males and females; but. 
after the manner of vegetable:, the young burfting 
from the bodies of their parents without any pre- 
vious impregnation. At the fixth generation, 
however, the propagation is fufpended ; the Gnat 
no longer produces it's like from itfelf alone, but 
requires the accefs of the male to give it another 
fucceffion of fecundity. 
The European Gnats give the human ipecics 
but little moleftation ; they are fometimes, indeed, 
heard humming about our beds in the night-time, 
and retard the approaches of fleep by the appre- 
henfions which they naturally excite: but the cafe 
is very difi-erent in the lefs populous and culti- 
vated regions of America, where the waters uao-- 
nate, the climate is v/arm, and v/here they are 
produced in inconceivable multitudes. There 
the whole atinofphere is frequently filled v/ith 
clouds of thofe famifiied infcClc, of different fizes, 
from the length of fix inches, to a minutenefs on- 
ly difcerniblc by the afUftance of the microfcope. 
The ardour of the meridian fun is too potent for 
their conftitutions, and they therefore Ihun his in- 
fluence: but when the evening fnades prevail, 
neither artifice nor flight can poiTibly fiiield the 
wretched inhabitants from their attacks; for, 
though myriads are deftroyed, myriads more con- 
ftantly fucceed them, and produce unceafing an- 
noyance. The native Indians, who anoint their 
bodies, with oil, and are from their infancy habi- 
tuated to the depredations of thefe creatures, find 
them far lefs troublefome than thofe perfons who 
are but newly arrived from Europe: the former 
fleep in their cottages having their bodies almofl; 
entirely covered with thefe infefts, and enjoy, not- 
withftanding, uninterrupted repofe; while the lat- 
ter are almoft driven to diuraftion, neither re- 
maining quiet by day, nor fleeping by night. 
The numbers of ipecies of the Gnat kind, in- 
cluding the larger and fmaller ones, are beyond 
the art of the moft flcilful naturalift to enumerate. 
Derham obferved near forty different Ipecies in 
the vicinity of Upminfter in Eflfex; but thofe 
which arrive at a fize capable of being remarked 
with the naked eye are by no means innumerable. 
All the Gnat tribe have a long cylindric body, 
compofed of eight wings; the corfelet is fliort, 
but large, in proportion to the fize of the fly; and 
to this member are affixed fix legs, the wings, and 
the balancers: four ftigmata are alfo found in this 
part, as is the cafe in other flies ; the two firft of 
v/hich are placed near the head, and have fome- 
times been miftaken ior ears. 
I Jnnffius defcribes the fix fubfequent fpecies. 
Gnat, Dusky, with a forked Inout. This fpe- 
cies is afli-colourecl, and moderately large: it has 
no points on the wings; and from between the ]aws, 
or more properly from the trunic, proceeds a fork-» 
ed dart. Ray fuppofes this to be the female of the 
domeftic tipula, becaufe it neither bites nor ftings. 
Gnat, Ash-Coloured, with eight rings on 
the body. This is the common Gnat, which is 
feen in almoft every country; and is too well 
known to require any farther defcription. 
Gnat, with water-coloured wings, marked 
with three black fpots. This fpecies is by fome 
authors called the leaft Gnat with blackifli fpots ; 
the body is of a brownifli colour, and no bigger 
than a fmall flea; and the wings are white, nar- 
row, and marked on their exterior edges with three 
dark fpecks. 
Gnat, Black, with water-coloured wings, 
black feet, and a white ring. This fpecies abounds 
in 
