634 
tually moving them forward ; yet the hard 
crust with which they are invested, and their 
shortness in flies and other insects, would induce 
one to believe them not to he the organs of 
touch: Mr. Barbut supposes them to constitute 
ortocontain the organs of hearing, because thev 
are tubular, and filled with air and some kind of 
humour, as appears from the antennae of but- 
terflies immersed in water. To come now 
to the terms of the art. A knowledge of the 
external parts of the body is first to be esta- 
blished; which, after the method of anato- 
mists, we may divide into head, trunk, abdo- 
men, and extremities. 
Of the external parts of the body. 
I- Caput, the head. It is asserted in the 
Fundamenta Entomologia?, that this part in 
Insects is without brain. The difference 
between the brain and spinal marrow con- 
sists in the former being a medullary part or- 
ganized. We do not deny the existence of 
a medullary thread in the heads of insects, 
but we never could discover it to be orga- 
nized; hence the hippobosca equina, or horse- 
fly, will live, run, nay even copulate, after 
being deprived of its head: to say nothing of 
many others which are capable "of living a 
long while under (he same circumstances. 
Insects not being apparently furnished 
with ears, they have been apprehended in- 
capable of hearing; as we can no more con- 
ceive that sense to exist without ears, than 
vision without eyes. That they are never- 
theless susceptible of any shrill or loud noise, 
as well as fishes, is indisputable ; but it has 
been supposed to be in a manner different 
from that of hearing. Mr. Barbut, however, 
supposes them to possess this sense in a very 
distinct manner. Many insects, he observes, 
are well known to be endowed with the power 
of uttering sounds, such as large beetles, the 
bee, wasp, common fly, gnat, &c. The 
sphinx atropos squeaks, when hurt, nearly 
as loud as a mouse. Now, if insects are en- 
dowed with the power of uttering sounds, it 
certainly must be for some purpose. As 
they vary their cry occasionally, it must be 
certainly designed either to give notice of 
pleasure or pain, or some affection in the 
creature who possesses it. “ The know- 
ledge of their sounds (says our author) is un- 
doubtedly confined to their tribe, and is a 
language intelligible to them only ; saving 
when violence obliges the animal to exert the 
voice of nature in distress craving compas- 
sion ; then all the animals understand the 
doleful cry. For instance: attack a bee 
or wasp near the hive or a few of them: 
the, consequence of that assault will be, the 
animal or animals, by a different tone, of 
voice, will express his or their disapprobation 
or pain-; that sound is known to the hive to 
be plaintive, and that their brother or bre- 
thren require their assistance; and the of- 
fending party seldom escapes with impu- 
nity. Now, if they had not the sense of 
hearing, they could not have known the dan- 
ger their brother or brethren were in by the 
alteration of their tone.” 
A still more decisive proof occurred'to his 
observation in a large spider in St. James’s 
park. I his creature had made a very lar^e 
web on a wooden railing ; and was at the 
time of observation, on one of the rails at a 
considerable distance from the place where a 
targe fly had entangled itself. Nevertheless, 
ENTOMOLOGY. 
the moment the fly was entangled, the spider 
became sensible of it ; though from the si- 
tuation ot the rail, he could not possibly have 
seen it. In this, however, Mr. Barbut might 
possibly be deceived ; because the spider was 
perhaps alarmed by the tremulous motion of 
the threads, occasioned by the fluttering of 
the fly ;_ which he might well know how to 
distinguish from their .vibration by the wind. 
The organ of hearing, in our author’s opinion, 
is situated in the antennae; both from their 
situation in the part of the head most favour- 
able to such organs, and their inward structure 
being moveable; the ears of the most inferior 
animals being so. He has never considered 
the antennae as either offensive or defensive, 
but has observed them to have been endowed 
with an exquisite sense of feeling ; that the 
animal appeared to be in agony when its an- 
tenna; were pinched ; and that it takes care 
to avoid the touching any hard substance with 
them roughly. “ This tenderness in the 
organ ot hearing (say s he) is edmmon to all 
animals ; and insbets seem to be particularly 
tender in these parts, by quickly withdrawing 
them from the touch.” 
This writer further observes, that the an- 
tenna; ot all insects are composed of joints 
varying in size, form, and number. Those 
who are chiefly confined to live under water, 
have their antenna; in general shorter than 
those who live on land. Some who roam at 
large in the air, have them long and slender, 
t hey are all hollow, and are rendered flexi- 
ble by the joints, which are very visible in 
the horns of the crab and lobster" Tliis hol- 
lowness, in our author’s opinion, is to receive 
the sound communicated to the extremities 
of the antenna; by the repercussion of the air 
affected by any noise; and conveys it, by 
means of the joints, from one to another, till 
it arrives in that lessened degree of tone 
best suited to the timid nature of the animal. 
In this circumstance there may be many va- 
riations in point of perfection in those organs ; 
the strength, utility, and degree of power in 
receiving sound, being proportioned to the ne- 
cessities of the animals, different in their na- 
ture and requisites. In most animals, the 
entrance to the auricular organ is patulous : 
but in this case the animal would suffer great 
inconvenience from such an organization, as 
the oritice would be subject to impediments 
from dirt, & c. 
Most naturalists are in doubt whether insects 
have the sense of smell, no organs being 
found in them adapted to that purpose : and 
although it was evident they had a perception 
of agreeable and fetid effluvia, it was thought 
to be. in a manner altogether unknown to us. 
Mr. Barbut is of opinion that the organs of 
smell reside in the palpi or feelers. Many 
insects have four, and some six, two of which 
are in general chiliform, in order to assist 
the insect in conveying its food to its mouth. 
It may be likewise observed, tiiat the palpi 
are in a continual motion ; the animal thrust- 
ing them into every kind of putrid or other 
matter, as_ a hog would his nose, smelling 
and searching after food. Insects which ap- 
parently do not possess palpi or spiral tongues, 
have undoubtedly some organ concealed, 
within the mouth, analogous to them In func- 
tion and utility ; the fleshy proboscis of the 
fly is thrust into every substance in which 
the animal expects to find food ; and when it 
is extended, nearly in the middle are situated, 
in our author’s opinion, two upright palpi, 
which, no doubt, perform in their turn some 
office, and perhaps that of smell. 
Many insects are without the tongue, nor 
do they make any sound with their mouths ; 
but for this purpose some use their feet, 
others their wings, and others some elastic in- 
strument with which they are naturally fur- 
nished. 
Eyes. Most insects have two eyes ; but 
the gyrinius has four, the scorpion six, the 
spider eight, and the scolopendra three, 
i hey have no eyebrows, but the external 
tunic ot the eye is hard and transparent like a 
watch-glass ; their eyes have no external mo- 
tion, unless it be in the crab. They consist 
for the most part of one lens only ; but in 
those of the butterfly, diptera, and many of 
the beetles, they are more numerous. Pugett 
discovered 17,325 lenses in the cornea of a 
butterfly, and Lieuwenhoek 800 in that of a fly. 
Antenna;. The number o! these is generally 
two (unless four are allowed to some crabs), 
and placed on the fore part of head; they 
are peculiar to insects ; and are plainly dis- 
tinguishable from the tentacula of the vermes, 
in being crustaceous ; and from the palpi of 
insects, which are more numerous, placqjf 
near the mouth, and are sometimes want- 
ing- As the antenna: are of great moment in 
distinguishing the various kinds of insects, we 
shall enumerate and explain the several dif- 
ferent forms of them. 
Setacex, are tiiose which grow gradually 
taper towards the extremity. 
Fiiiformes, such as are oi'the same thickness 
throughout. 
Moniliformes, arc fiiiformes, like the pre- 
ceding, but consist of a series of round knobs* 
like a necklace of beads. 
Ctavate, such as gradually increase in size 
toward the extremity. 
Capitals arc davate, but have the extre- 
mity somewhat round. 
Fissijes are capitate ; but have the cap?- 
tulum, or knob, divided longitudinally into 
Ihree or four parts, or lamina*, as in sca- 
rab a* i. 
Perfoliate are also capitate ; but have 
(he capitulum horizontally divided, as in the 
dennestes. 
Pectinate, so called from their similitude 
to a comb, though they more properly re- 
semble a. feather, as in the moths and elateres: 
this is most obvious in the male. 
Aristate, such as have a lateral hair* 
which is either naked, or furnished with lesser 
hairs, as in the fly. 
Breviores, those which are shorter than the 
body. 
Longiores, those which are longer than the 
body. 
Mediocres, those which are of the same 
length with the body ; all three of which 
varieties are distinguishable in the ceram- 
byces. 
Palpi, or feelers, resemble filiform, articu- 
lated, moveable antennae. They are most 
commonly four in number, sometimes six ; 
they are sufficiently distinguished from an- 
tenna*,, in being naked, short, and always 
placed at the month.. 
Os, the mouth, is generally placed in the 
anterior part of the head, extending somewhat 
downwards. In some insects, it is placed 
under the breast; as in the chermes, coccus* 
cancer (crab), and curculiou 
