Weekly national intelligencer., 1851-02-15
SMITHSONIAN LECTURES.

DR.. GoADBr commenced his lectures Monday evening
last on the structure and functions of insects, with brief
description of his oxyhydrogen microscope, which differs in
its principle fcoRstrucion from such instruments generally
being reaectng instead Of refrac.ing microscope.
In the introduction the lectures he alluded the great
beauty of insects their universal distribution their close ea
ton the external world and its inhabitants and the pod
gous number of species known entomoogists exceeding
in this respect all the known species Of animals and plants
combined.
The characters which distinguish insect next de-
scrbed aud these stated to be the division of the body
into three distinct portions, into head chest and abdo
men, with the possession when in their perfect state of three
pairs of legs.
The Linnean classification of insects explained and
illustrated by preparation consisting of group of wings,
selected from the Lnnean ORDERS showing at view the
principles of that system.
The transformation Of insects, in connexion with the
gradual development Of their organic structures, next
examined. All insects pass through four distinct stages
the egg, the ap Cor caterpillar the pupa and the imago
perfect insect Those insects that quite dssmar in
the three latter stages Of development the butterflies,
said to possess perfect meamorphoss in conadsinction
those (crckets, grashoppe) which present the
general appearance casual observation and have mpe
feet metamorphoss This illustrated by skin of a
dragon-f and Of a cockroach.
DR.. GoADBI commenced his lecture Of Wednesday
ing the Structure and Functions of Insects by stating that
the active organs Of defence in insects obtain their highest
development in the bees wasps hornets, and their
This he illustrated by preparations Of the sting Of
solitary bee and the honey bee showing the glands that
crete the poison, and the bag in which the secretion is
tanned for when occasion may require it. Allied to the
structure Of the sting is the ovposto Of the chneumon es
and while he demonstrated the preparations Of the eggayng
apparatus, the lecturer gave brief history of the very
ous proceedings of this extensive family of insects They
are all OF them parasitic in their habits deposing their eggs
wn ne bodies Of other insects in the egg, side by
sue In the nest with the egg of other insect the in
oeng that the young ichneumon when hatehed may
find an abundant supply of food in the creature placed in ap
position with it.
The consideration Of the nutive function was ner in
order and the structure Of the mouth and its cr;ons od
cation in the orders of insects respectively was s,,,od n
described to extent The examples cons,.ted of ho
mandbuate mouth Of the beetle tribe the sucorial month G
the free bugs, the bees, butterflies and es All
though the end to be obtained precisely the same viz be
transmission Of the OF plants in the case Of the hoes
the delicious nectar Of flowers in other insects the blood
OF animals yet the for the accomplishment of this
great object very various and essentially different So
far as the mechanical arrangement Of parts is concerned no
two preparations alike but each form Represented TO
be perfect Of its kind Some of these instruments ca
pabe Of infcng wound in the integument of either
plant an anima-piercng instruments, lancets &C. The
mode by which the fluids conveyed into the instrumental
organs Of these insects after the external wound made will
be considered In the next lecture. Il