FLY 
FLY 
tKe gnat kind, and having a mouth without any 
teeth, belongs to the fecond clafs. 
The, four-winged Flies, which are extremely 
numercvis, fill up the two remaining clafles. All 
the bee kind have a trunk and two teeth; all the 
wafp kind have a mouth furnifhed with two teeth; 
and, befides thefe, there are feveral four-winged 
Flies which have the characters of the fecond 
clafs, particularly all the papilionaceous Flies, 
J)roduced from water tsenias, which have a mouth 
without any teeth. Several fmall four-winged 
Flies alfo belong to the firft clafs ; fuch as the fly- 
ing pucerons, and the falfe pucerons, which have 
all trunks without teeth; and to this clafs likewife 
the cicadie are properly referred. 
A fifth clafs may likewife be eftablifhed, but it 
only comprehends two known fpecies of Flies ; this 
is fuch whofe heads perform the office of trunks . Flies 
cf this kind have very long heads, terminating in 
a fort of beak, fomewhat like the feathered tribe; 
but this beak has no aperture except at the extre- 
mity; nor can the Fly alter it's pofition without 
altering that of the whole head. At the end of 
this kind of trunk are placed the teeth, or other 
organs, with which the infedl collefts it's food. 
Tlie fcorpion Fly, a very beautiful creature, fre- 
quently feen flcipping and leaping about flowers, 
affords a fpecimen of this kind. 
Subordinate to thefe general clafles, others are 
deduced, from whatever forms the moft obvious 
and efl^ential diftinftion between thefe little ani- 
mals. The figure of the body often prefents fuch 
difl;in6lions; and from it three fubordinate clafl!es 
are formed under the five general ones : the firfl: is 
compofed of thofe Flies whofe bodies are fliort and 
broad; the fecond, of thofe with long bodies; the 
third, of thofe whofe bodies are f;ifl:ened to the 
corfelet only by a fine filament; and, under all 
thefe, the feveral genera are to be efl:abliflied from 
other inferior but conftant and invariable marks, 
fuch as the manner in which they carry their wings, 
the figures of their antenns, the pofition of their 
trunks, and other efl^ential variations. 
The bodies of Flies being extremely different 
from each other, even thofe whofe general confor- 
mation refers them to the fame clafs, are not with- 
out their diftinftions, by which alone they may be 
made to eftablifli fubordinate genera. Among the 
Flies which have fhort or ellipfoide bodies, fome 
are extremely flat and thin ; fuch are thofe of the 
Flies produced from worms feeding on the pu- 
cerons; and others have the hinder part of the 
body incurvated in the form of a hook. 
In Flies, the extremity of the body is ufually 
fmaller than the adjoining parts; but there is a va- 
riety found in the nefls of fwallov/s, the extremity 
of whofe body is confiderably the largefb. How- 
ever, not only the form of the body, but the dif- 
ferences in the filament, by which in many genera 
it is connected to the corfelet, may furnifli marks 
for the difl:in6lions of the fubordinate genera. The 
hinder part of the body may alfo furnifh abundant 
matter of diftinftion. Thofe Flies which carry 
flings in their tails, have in that circumfliance alone 
a fufficient difl:in6tion. But, exclufive of thofe 
which have fl:ings, the females of feveral genera 
have organs placed in the extremities of their bo- 
dies, which ferve as a kind of auger to pierce the 
body in which they are to depofit their eggs. Se- 
veral of the female ichneumons are furniflied with 
this kind of infl:rument ; and there are others which 
have a long and (harp piercer, partly lodged un- 
der the belly, or in the body; of which kind are 
the cicadse, and many others. Nor is this the 
only provifion which nature has afforded thefe 
creatures for their protcftion or defence; fome 
have a ferrated organ behind; and others one or 
more long flender filam.ents, which in their form 
and fl:ru6lure have fome refemblance to the anten- 
nas. The genera of Flies may therefore very pro- 
perly be diflringuiflied by fuch appendages : the 
ephemerons, and many other fpecies among the 
four-winged Flies, are furniflied with them ; and, 
among the two- winged kinds, the fmall Fly, which 
is the male gall infeft, affords an example of 
them, 
Thofe Flies which proceed from water-worms, 
according to their feveral fpecies, prefent fome va- 
rieties to the curious in the manner of their egrefs 
from their fliells, when they quit the nymph ilate, 
in order to affume their lafl: and mofl: perfedl form. 
The long water- worms, compofed of many rings, 
and with funnel-fafhioned tails, confl:ru6ted with 
apertures for the admiffion of air, and furrounded 
with a multitude of hairs, retain in their flieil-fliate 
fo much of their original form, that they are not 
eafily difliinguifhable. In each of thefe, the nymph 
occupies only a fmall part of the cavity ; and, in 
many of them, the Fly is produced perfe6l in five 
or fix days. At the expiration of this time, the 
nymph, having acquired it's full flrength, begins 
to exhibit the firfb indications of life in attempting 
to obtain it's liberty. To accomplifli this, nature 
has fo provided for the inclofed Fly, that the head 
is but nightly connefted to the fecond ring of the 
body; but the creature, in this fl:ate, not being 
lodged in that part of the worm, can make no ef- 
forts againft it; all it's exertions are applied to 
force an aperture in the fecond ring, like that in 
the back of the caterpillar's flcin when it is about 
to cafl: it's exuvise. For this purpofe, the inclofed 
Fly inflates and fwells it's head; and then thrufl:s 
out the bladder from it's anterior part, with which 
thefe Flies are provided, in this ffage of their exifl:- 
ence, on this very account. When this aperture 
is efftfled, the head of the worm is in fome mea- 
fure feparated from the body; and the efforts of 
the Fly to pufli itfelf forward, finifh that fepara- 
tion, and leave an opening of a proper fize for the 
egrefs of the Fly. 
The Flies produced from this fpecies of worm 
are liable to confiderable danger from the element 
which formerly nouriflied them ; and they are as 
eafily drowned as thofe produced from worms 
which fpend their lives on dry land. Thefe Flies, 
which are of the fhort-bodied kind, bear a flironor 
affinity to the comm^on great blue flefli-flies ; they 
have fiefliy trunks furnifhed with lips, and are 
deftitute of teeth ; but, though thus far tiie fimi- 
larity is entire, the chara6lerifl:ic diftindions are 
fufficiently obvious. The firft is, that the antennse 
of this fpecies are compofed of granulated fila- 
ments; whereas thofe of the other are of the 
battledore kind: the wings of the flefh-fly are not 
croffed on tlie body; whereas thofe of this Fly are. 
But the moft confpicuous variation is, that it has 
two oblong and flender bodies, of a cruftaceous 
ftrudlure, inferted in the upper part of the corfelet, 
and dire(5led backwards. 
Some of the more remarkable fpecies of Flies 
are as follovi'; others are arranged according to 
their names. 
FLY, BREEZE, or GAD-FLY. See Gad- 
Fly. 
Fly, 
