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ENTOMOLOGY. 
ENTOMOLOGY. 
ITS RELATIONS TO AGRICULTURE, AND ITS PRO- 
RESS IN MISSOURI. 
With Brief Instructions for Collecting, Preserving, and Studying Insects, 
By CHAS. V. RILEY, Srate Enromo.ocist. 
DEFINITION OF ENTOMOLOGY. 
It would seem almost superfluous to define the meaning of this 
word ; but from the many letters that come to me addressed “ State 
Etymologist,’’ it is evident that there are those who yet imagine 
that my office is somehow or other connected with philological 
science. For the benefit of such, then, Entomology is derived 
from the Greek, (evrouov, insect, Joyoc, aiscourse,) and constitutes 
that branch of Natural Science which treats of Insects. 
WHAT, THEN, IS AN INSECT ? 
The term ‘‘ Insect’’ is derived from the Latin s¢nsectum, which 
signifies ‘‘ cut into,’’ and expresses one of the chief characteristics 
of this class of animals ; but we can only obtain an intelligent idea 
of what constitutes an insect by comparison with other animals. 
THE ANIMAL KINGDOM. 
Animals are variously classified by zGologists, but the best known 
and most comprehensive system of classification is that called the 
Cuvierian, which separates them into four great Branches or Divi- 
sions. ‘These are ; 
I—VERTEBRATA or Backbone Animals, comprising the four 
respective classes of Mammaiia (mammals), Aves (birds), Reptilia 
(reptiles), and Psces (fishes.) Normally these all have four limbs 
and an internal skeleton to which the muscles are attached. 
2—ARTICULATA or Jointed or Segmented Animals, comprising 
the five classes of /xsecta (insects), Arachnida (spiders, mites, etc.), 
Crustacea, (crabs, lobsters, etc.), Afyriapoda (thousand-legged 
worms), and Avznelida (true worms, as leech, earthworm, etc.). 
These animals are readily distinguished by their jointed or seg- 
mented nature. It is plainly seen in a caterpillar as it crawls 
along ; each joint moves one after the other, with its own peculiar 
motion ; each has its separate set of organs, so that a caterpillar 
may be said to have a head and 12 distinct bodies attached, for 
which reason it has 4,000 muscles to move its body, while man has 
only 529. The jointed character is seen even in the Earthworm 
ard in the Leech, but not in the slug, which is a Molluscous—not 
an Articulate animal. Articulates are further characterized by 
having no internal skeleton ; they wear their skeleton on the outside, 
and every one must have noticed the close resemblance which the 
exterior of the limbs of a grasshopper or of a lobster bear to the 
bones of our own limbs or to those of other Vertebrates. SipNEY 
SmitH wished that, in hot weather, he could put off his flesh and 
sitin his bones. He ought to have been an Articulate! It is true 
that some Articulates, and almost all insects in their young or 
larval days, have this outer skeleton quite soft and delicate; but 
the same may be said of the internal skeleton of Vertebrates. We 
may crush and crunch with ease the bones of a newly hatched 
chick ; but he who would undertake to do likewise by those of an 
old rooster, would, I fancy, have a rather tough job of it! 
3—Motvusca or Soft-bodied Animals. These are without dis- 
tinct joints, and have neither internal or external skeleton, the 
surface being soft, flexible and retractile, and often covered with 
calcareous deposits which assume a variety of different forms. 
4—Raopiata or Star Animals. These have the body arranged 
on the plan of an asterisk (*), radiating from a common centre. 
They are often called zéophites, and comprise the very lowest 
animals,—some of which, as the sponges, corals, etc., were for a 
long time considered plants, and do, indeed, connect the Animal 
and the Vegetable Kingdoms. 
With the exception of a few Molluscous snails and slugs, the 
animals of the last two Branches live almost entirely in water, and 
we see that an Insect belongs to the second great Branch, and that 
it shares the jointed or articulate structure in common with the 
other animals of that Branch. Wherein, then, does it differ from 
them? Briefly, in having only 13 joints to the body,* and in the 
adult stage 6 true, jointed legs, and usually (not always) wings. 
The five classes of Articulates differ from each other in the number 
of legs they possess in the adult form, as follows: /nsecta, 6 legs ; 
Arachnida, 8; Crustacea, 1o—14; Myriapoda, more than 14; An- 
nelida, none, 
I say TRUE legs and in the apuLT form, because there are some 
mites (Class Arachnida) which, when young, have six legs only, 
while many insects have additional legs in their preparatory or 
adolescent stages, which are not jointed, but membranous, and are 
lost in the perfect stage ; these are called false, sham, or pro-legs. 
Insects are further characterized by having the body divided into 
three distinct parts, the head which bears the sense organs, the 
thorax which bears the organs of locomotion, and the aédomen 
which bears the reproductive organs. They also undergo a series 
of molts and exist in four distinct stages; 1st, the egg stage; 2nd, 
the /arva (meaning masked—the future and ultimate form being 
usually masked or hidden, so far as external appearance goes) or 
active stage ; 3rd, the upa (sometimes called chrysalis or nymph) 
or usually quiescent stage ; 4th, the smago or perfect stage, in which 
alone the wings appear. To be brief, then, I would give the follow- 
ing definition of an Insect: A 13-jointed, 6-legged animal, with 
an external skeleton; undergoing transformations or metamorphoses, 
and breathing through spiracles (breathing holes,) which lead to 
trachea (air tubes); the body in the adult divided into three distinct 
parts (head, thorax, and abdomen) ; with or without wings. 
IMPORTANCE OF ENTOMOLOGY AS A STUDY. 
Time was when the entomologist was looked upon as a mere, 
trifling enthusiast. The derisive term ‘‘ Bug-hunter’’ was applied 
to him as though his sole occupation in life was to run after and 
catch ‘‘bugs.’’ So long as he contented himself with such trivial 
doings the epithet was, perhaps, not undeserved: but that day has 
long since passed away! A whole galaxy of illustrious names— 
SCHWAMMERDAM, Ray. R6sEL, R&éaumuR, D=® GEER, LATREILLE, 
Linnzus, Fapricius,. Kirpy, SPENCE, Harris, Say, and others, 
of days gone by; and hundreds of others of the present day— 
stand forth to redeem the science of entomology from such 
* An additional subjoint is often apparent. 
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