172
T he mouth is a part of the infecl to which the naturalifl
will find it neceflary to pay a very particular attention: Fabri-
cius goes fo far as to affert, that without a thorough knowledge
of the mouth, it’s form, and various appendages, it will be im-
poffible ever to difcriminate with accuracy one infeft from another.
In the ftru&ure o f the mouth confiderable art and wif-
dom is difplayed: the diverfity in the figure is almoft as great
as the variety o f fpecies: It is ufually placed in the fore part of
the head, extending fomewhat downwards ; in the chermes,
coccus, and fome other infefts, it is placed under the breaft.
Some infeas have their mouths armed with ftFong jaws, with
which they bruife and tear their food: however fine and delicate
thefe organs may appear, they are really hard, and in fome
fpecies fufficiently ftrong to pierce the hardeft wood. Others are
fumilhed with a kind o f tube or tongue, at one time moveable,
at another fixed: with this they fuck the juices o f the flowers.
In fomea gain the tongue is fo Ihort as to appear to us incapable
o f anfwering the purpofe for which it was formed, and the oeftsi
appear to have no mouth.
The roftrum, or probofcis, is the mouth drawn out to- a rigid
point. In many infefts o f the hemiptera clafs it is bent downward
towards the breaft and belly.
The jaws are generally two in number, lometimes four, and
at others more; they are placed in an horizontal direftion . the
inner edge, in fome infeas, is ferrated, or fumilhed with final!
teeth.
The tongue is in general a taper and compaa inftrument, ufed
by the infea to extraa the alimentary juices on which it feeds:
fome
fome can extend or contract it.; others roll up their’s with dexterity
• in fome it is inclofed in a {heath, with the pointed end of
which they pierce the fubftances which contain their food, and
then extraa the juice with their tongue ; in many it is placed in
a groove under the belly; taper and fpiral in the butterfly ; tubular
and flelhy in the f ly ; in fome it is long, and in others fliort,
but in all affording a fupd of amufement for the microfcope. ,
M De Geer * has given us an account of a very curious cir-
cumftance concerning the tongue o f the papillon de faules.+ Having
cut off the tongue from the butterfly, almoft as foon as it was
emancipated from the chryfalis, it moved and rolled itfelf.up at
intervals for a confiderable time : an hour after it had been cut
off it repeated the fame motions, recommencing them every time
it was touched. The fame effeft does not follow if the butterfly
has been freed from the chryfalis a few days.
The ftrufture o f the eye is, in all creatures, a moll admirable
niece of mechanifm, but in hone more fo than m thofe of mfc&s :
there is no part of thefe fmall creatures which exhibits more
clearly the prodigious art with which they are organized, and
{hews how many wonders eft-ape the natural fight of man. The
eyes are very different in different fpecies, varying m number,
fituation, connexion, figure, and fimphaty of conftruftion. The
greater part have two eyes, but in the monoculus they approach
i nea, L each other „ • » 1 1 M « • • f f l K & K E
* Dc Geer, Memoires pour fervir a L’Hifloire des Infeftes, tom p 77
+ Papilio Antiopa, Lin. Syll. Nat. p. 776. N 165-