2 - INTRODUCTION. 
has an undulating motion, which, with the help of the flime that covers: 
_ their bodies, they can move flowly forward, and adhere to every fur- 
* face at pleafure. F 
The fecond fort of infeéts are flies of various kinds, whofe bodies are’ 
covered by fmall plates not unlike our ancient armour, the pieces of 
which are lengthened by unfolding, and fhortened by running over 
each other. Thefe lead a more luxurious life, transfer themfelves- 
from place to place with rapidity, and fpend their little exiftence in 
feafting and propagating their kind. ; : 
‘The third fort are ants, {piders, and others, whofe bodies are divid= 
éd into two or three portions, joined by a fort of ligament. Of all the 
race of reptiles thefe feem to be endowed with the greateft fhare of fa- 
gacity. ‘Ihe wifdcem of the ant, and it’s well formed commonwealth, 
is too well known to be infifted on; but the fpider, though it leads a 
folitary and rapacious life, feems endowed with even fuperior inftinéts. 
Its various artifices to enfnare its ‘prey, and, when no longer able to 
fupply a new webritfelf,. the Aratagems it lays to. get poffeffion of that 
belonging to another, are evidences of its cunning. : 
The minutenefs of infeéts may render them contemptible in the eyes 
of the unthinking; but when we confider the art and mechanifm in fo 
minute a ftruéture, the fluids circulating in veifels fo fmall as to efcape’ 
the fight, the beauty of their wings and covering, and the manner in 
which each is adapted for procuring its peculiar pleafures, we fhall find 
how little difference there is between the great and little things of this 
life, fince the Maker of all, has beftowed the fame contrivance in the 
formation of the elephant and the ant. : 
‘The ftructure uf the eye in infe@ts is remarkably different from that 
of other creatures in feveral refpedts. It is defended by its own hard- 
nefs againf external injuries, and its cornea,. or outer coat, is all over 
divided into lenticular facets, and through the microfcope appears as 2° 
beautiful piece of lattice work. Each-hole in this-is of fuch a nature, 
that when looked through, every objeét feems inverted. This mecha- 
nifm alone fupplies the place of the cryftalline humour, which is not 
to be found in infe&s. Spiders have generally eight eyes, and flies 
may be faid to have as many as there are perforations in the cor- 
nea. Other creatures are obliged to turn their eyes different ways to’ 
behold objects, but fies have them fo contrived as to take in every ob- 
ject near them at once. In order to keep their eyes clean; they are 
provided with two antennz, or feelers. Some however are of opinions. 
that they clean their eyes with their fore legs as well as the feelers; nor 
is this conjecture ill founded, when we confider, that in fome forts, par- 
ticularly the fleth fly, the feelers are too fhort for this purpofe, and’ 
therefore their legs alone can fupply the defect. : 
‘Yhe mechanifm in the feet of flies, and other infetts,. deferves alfo 
our notice. ‘Che amphibious infects, which are obliged to live by land: 
as well.as water, have their hindmoft legs made with commodious flat 
joints, having griltles.on each fide ferving for oars to fwim with, and 
placed at the extremity of the limb;.but nearer the body there are two 
fil fupporters to enable them to walk when they have occafion. In 
thofe infets whofe motions are performed by leaping, fuch-as the grafs- 
hopper and cricket, their thighs are ftrong and brawny ; thofe, on the 
contrary, which uf their claws in perforating the earth, have fuch: 
: j : parts 
