WATURAL HISTORY. 139 
folour of the fpecies, as green, if they be green, and of a fanguine 
hue, if they be red. 
_ Thefe are circumftances fufficiently extraordinary in the life of this 
ittle anitnal, but it offers fomething fill more curious in the method 
of its propagation. However fimilar infeéts of the gnat kind are im 
their appearance, yet they differ widely from each other in the manner’ 
in which they are brought forth, for tome are oviparous,- and are pro- 
duced from eggs, fome are viviparous, and come forth in their moft 
Perfe&t form; fome are males,-and unite with the female; fome are 
females, requiring the impregnation, of the male; fome are of neither 
fex, yet fill produce young, without any copulation whatioever.. This 
is one of the ftrangeft difcoveries in all Natural Hiftory? A gnat fepa- 
tated from the reft, and inclofed in a glafs veffel, with air fufficient to — 
eep it alive, fhall produce young, which alfo, when feparated from 
€ach other, fhall be the parents of a numerous progeny. Thus, down 
for five or fix generations do thefe extraordinary animals propagate 
Without the ufe of copulation, without any congrefs between the male 
and female, but in the manner of vegetables, the young burtting from 
the body of their parents, without any previous impregnation. At the 
fixth generation however, their propagation flops, the gnat no longer 
produces its like, from itfelf alone, but it requires the accefs of the 
Male to give it another fucceflion of fecundity. 
The gnat of Europe gives but little uneafinefs; it is fometimes heard 
to hum about our beds at night, and keeps off the approaches of fleep 
by the apprehenfion it caufes; but it is very different in the ill-peopled 
regions of America, where the waters ftagnate, and the climate is 
Warm, and where they are produced in multitudes beyond expreffion. 
The whole air is filled with clouds of thofe famifhed infects, and they are 
found of all fizes, from fix inches long, to a minutenefs that even re- 
quires the microfcope to have a diltin@ perception of them. The 
warmth of the mid-day-fun is too powerful for their conftitutions; but 
when the evening approaches, neither art nor flight can fhield the 
wretched inhabitants from their attacks, though millions are deftroyed, 
Rill millions more fucceed, and produce uncealing torment. ‘he na- 
tive Indians, who anoint their bodies with oil, and who have from their 
infancy been ufed to their depredations, find them much lefs inconve- 
nient than thofe who are newly arrived from Europe; they fleep in 
their cottages covered all over with thoufands of the gnat kind upon 
their bodies, and yet do not feem to have their flumbers interrupted by 
their cruel devourers. If a candle happens to be lighted in one of 
thofe places, a cloud of infeéts at once light upon the flame, and ex- 
tinguith it; they are therefore obliged to keep their candles in glals lan- 
orns ; a miferable expedient.to prevent an uncealing calamity. 
S2 : CHAP. 
