ENTOM 
*nd ef hearing, others have fuppofed them appropriated 
to. a<.delicate kind of feeling, fenfible to the lead motion 
or difturbance in the circumambient fluid in which they 
move. It is very reafonable to fuppofe they are the or¬ 
gans of fmelling, fiuce we evidently find that many infects 
polfefs this fenfe in a very exquifite degree, and yet we 
fee no external organs except thefe to ferve that purpofe. 
The following obfervations may ferve to throw fome light 
on this obfcure fubjeCt. When a winglefs infect is placed 
at the end of a twig, or in any other fituation where it 
meets with a vacuity, it moves the antenna: backward 
and forward, elevates and deprefles them from fide to 
fide, and will not advance further left it Ihould fall. 
Place a ftick or any other ftibflance near the antennae, and 
the infeCt immediately applies them to this new objeCt, 
feems to examine whether it be fudicient to fupport its 
weight, and then proceeds on its journey. From thefe 
obfervations it would appear that the antennae a Hi ft the 
infeCt in judging of the vicinity of objeCts, and probably 
enable them to walk with lafety in the dark. 
That thefe obfervations are not, however, conclttfive, 
appears from an experiment of a very ingenious naturalilf : 
being defirous of afcertaining the nature and life of the 
antennae and prcbofcis of a butterfly, he gently approach¬ 
ed one that was flying about in fearch of food ; he ob- 
ferved that it turned the antennae about every way, till 
coming within fcent of a flower, it kept them fixedly 
bent toward that objeCt, directing its courfe by their 
guidance, till it arrived at the flower ; there they ap¬ 
peared to aCt as an organ of fmell, and that the minute 
•holes with which it is furniflied afiifted in promoting this 
operation. When the creature had reached the flower, 
.it hovered over it as with rapture, poifing itfelf quietly 
upon wing, like a kite or hawk in the air ; it then drop¬ 
ped fuddenly, till it was on a level with the flower, when 
it began to agitate its wings brilkly, and to unroll its 
fpiral trunk, thrufting it to the bottom of the flower; 
in a little time the trunk was rolled up, and again in a 
moment unrolled ; thefe operations it repeated till the 
flower yielded no more juices, the butterfly then fought 
for and alighted on another. But after all, this fubjeCt 
mud for the prefent remain undecided. Indeed, the 
bodies of infedts are throughout formed of parts fo dif¬ 
ferent from ours, that we can probably conceive no more 
idea of the ufe of fome of their organs, than a man born 
blind or deaf can of the fenfesof vifion or hearing. They 
may have fenfes different from ours, and thefe may be the 
inftruments of them. The differences in the form and 
confirmation of the antennae, are diftinguifned in entomo¬ 
logy by the following names :•— Setaceous, are thofe formed 
like a briftle, gradually tapering towards the point or ex¬ 
tremity, as in many of the phalenae. Filiform, are thread- 
fhaped, and of an uniform thicknefs. Monilifonn, are alfo 
of a regular thicknefs, but are made up of a feries of 
minute knobs, refentbling a necklace of beads, as in the 
chryfomela, Clavate, formed like a club, increafing gra¬ 
dually from the bafe to the extremity, as in the papilio, 
or butterfly. Capitate, alfo formed like a club, but the 
laft articulation is larger than the reft, finiftiing with a 
kind of knob or head. Fijfile, are like the former, ofily 
that the capitulum or knob is divided longitudinally into 
three or four parts or laminae, as in the fcarabaei. Perfo¬ 
liate, are alfo capitated, but have the knob divided hori¬ 
zontally, and the laminae connected by a kind of thread 
pafiing through their center, as in the dermeftes and dy- 
tifeus. Petdinate, fo called from their fimilitude to a 
comb, though they more properly refemble a feather, as 
in the phalenae and elateres ; this is moft obvious in the 
male. Arijlate, are fuch as have a lateral hair, which is 
either naked, or furnifhed with fmaller hairs, as in the 
fly.—Befides the foregoing terms, the antenna: are called 
breviores, or fhort, when they are fhorter than the body ; 
raediocres, or middling, when they are of the fame length ; 
and longiores, when they are longer. 
Near the mouth there is alfo a fpecies of fmall filiform 
Vojl. VI. No. 395. 
O L O G Y. 829 
articulated antennae, called the palpi, or feelers; they 
are generally four in number, fometimes fix ; they are 
placed under and at the fides of the ntouth, which fitua¬ 
tion, together with their fize, fufficiently uiitinguilh them 
from the antennae ; they are in continual motion, the ani¬ 
mal thrufting them in every matter, as a hog would its 
nofe, when in fearch of food. Some have fuppofed them 
to be a kind of hand to afiift in holding the iood when it 
is near the mouth. 
Eyes.— The ftruCture of the eye has always been con- 
fidered as a wonderful piece of mechanifm ; the admirable 
manner in which thofe of the human fpecies are formed, 
and the nature of vifion, are fpeculations which cannot 
but excite the attention of every inquifitive mind. The 
eyes of infects, though they differ conliderably in their 
conftruCtion from thole of other animals, are no lefs wor¬ 
thy of our admiration. Indeed, among the exterior parts 
of infetts, none are more deferving of minute inveftiga- 
tion, and very few perfons are to be found, who can be 
infenfibie to the beauties of this organ when exhibited 
under the microfcope ; which is the only means of difeo- 
vering the prodigious art employed in their organization, 
and evidently fhews how many curious objects efcape 
the unallifted fight. The conftruCtion of the eye in in- 
feCts is not only diftinCt from that of other animals, but 
alfo differs in different fpecies. They vary in number, 
fituation, connection, and figure. In other creatures the 
eyes are moveable, and two in number, one on each fide 
of the head: in infeCts, the genus of cancri excepted, the 
eyes are fixed ; they have no eye-brows, but the outer 
coating is hard and tranfparent. The greater part of in- 
feCts have two eyes; in the monoculus they approach fo 
near to each other, as to appear like one ; the gyrinus 
has four eyes, the fcorpion fix, the fpider eight, and the 
fcolopendra three. Of thefe eyes fome have them fingle, 
that is, placed in facets at a fmall diftance from each 
other; while others are furniflied with an indefinite num¬ 
ber of lenfes all placed in one common cafe or focket; 
and termed reticulated eyes. Thefe appear like protube¬ 
rances on the heads of infeCts, and we can perceive that 
they confift of a number of lines crofting each other like 
the meflies of a net. By this we know that they are re¬ 
ticulated fubftances ; but in what manner they are fo, can 
only be fhewn by the microfcope. 
The eyes of the libellula, or dragon-fly, are divided 
into a number of hexagonal cells, each of which forms a 
complete eye. The external parts of thefe eyes are fo 
perfectly finootlt, and fo well poliflted, that, wiien viewed 
as opake objects, they will, like fo many mirrors, refleCt 
the images of all the furrounding objects. The figure of 
a candle may be feen on their furface multiplied almoft 
to infinity, fhifting its beam to each eye, according to the 
motion given by the hand of the obferver. Other crea¬ 
tures are obliged to turn their eyes towards the objeCt. 
they defire to fee ; but infects have eyes directed thereto, 
on whatfoever fide it may appear; they more than realize 
the romantic accounts of fabulous hiftory : poets gave to 
Argus an hundred eyes; infeCts are furnifhed with thou- 
fands, having the benefit of vifion on every fide with the 
utmofteafe and fpeed, though without any motion of the 
eye, or flexion of the neck. Each of thefe protuberances, 
in its natural ftate, is a body cut into a number of faces, 
like an artificial multiplying glafs; but with this fupe- 
Tiority in the workmanftiip, that, as there every face is 
plane, here every one is convex, immenfely more nu¬ 
merous, and contained in a much fmaller fpace. Each 
of the eyes is an hexagon, varying in fize according to 
its fituation in the head, and each of them is a diftinct 
convex lens, and has the fame effeCt in forming the image 
of an objeCt placed before it. 
Hooke, Catalan, and other entomologifts, have fhewn 
that thefe fmall eyes are furniflied with every requifite of 
vifion, and that each of them has the ufe, the power, and 
properties, of an eye. But we mull have recourfe to the 
works of Swammerdam fora full account of the aftoni filing 
10 B organization 
