352 
ENTOMOLOGY.-NO. 1. 
ENTOMOLOGY.—No. 1. 
Much has been said and written upon the various 
modes of destroying insects injurious to vegetation, 
and of counteracting in a measure their injurious 
effects. W ere we to enumerate all that have been 
recommended by various writers on agriculture and 
gardening, it would surely be a matter of astonish¬ 
ment that the races of injurious insects had not 
long ago been exterminated, not that they should 
appear in such undue proportion as almost to baffle 
our exertions to destroy them. It must surely be 
confessed that in no one department, either of agri¬ 
culture or gardening, is there such a lamentable de¬ 
ficiency as in this. The reasons for it will be evi¬ 
dent, when it is remembered, that in order to check 
or counteract the operations of these numerous 
classes of depredators with any success, a know¬ 
ledge of the peculiar habits and economy of each 
species is first to be acquired; without this, little 
can be done of any account, and even the remedies 
that are applied are used at random. It may be 
said, and perhaps with some truth, that this subject 
belongs to the naturalist, and that the agriculturist 
and gardener should look to him for information, 
and for effective remedies. The naturalist studies 
out and explains the animal economy, but it remains 
for those most interested, those who daily see and 
feel their effects, to apply remedies which their pre¬ 
vious knowledge, obtained from the naturalist, will 
enable them to do. The agriculturist should devote 
a portion of his leisure moments in acquiring a 
perfect knowledge of the general forms which be¬ 
long to insects, the changes they undergo, and of 
the primary divisions into which they have been 
formed by modern naturalists. He should watch I 
their progress, note the manner of their feeding, 
mark the time they pass in their larva and pupa 
states, and the period of their becoming perfect in¬ 
sects. He should learn to distinguish between 
beneficial insects whose increase should be promot¬ 
ed, and injurious insects whose depredations should 
he arrested. 
In some future communication I may give to 
3 ^our readers, if desirable, a description of the dif¬ 
ferent operations which, in a general way, may be 
directed to the removal of insects; but, in this, I 
propose to give a general view of the changes 
which insects pass through, from the egg to the 
perfect state; the different appearances which the 
various tribes assume, before they reach their final 
development; and the several orders or divisions 
under which they are classed by modern naturalists. 
Insects are distinguished from vertebrated ani¬ 
mals by being destitute of a back-bone, and furnish¬ 
ed with more than two feet; and from worms, by 
possessing feet. Most insects are furnished with 
six feet, but some few have a greater number, as 
the centipede, wood-louse, &c. 
The generality of insects are produced from 
eggs; some are hatched within the body, and the 
young are produced in a living state ; while most 
others are hatched from eggs deposited in some se¬ 
cure place, either above or below the surface of the 
earth. The period required for these eggs to hatch 
is very variable; in some species this process 
takes place in a few days, while, with others, it is I 
not accomplished until the following year. 
Of the Larva or Caterpillar — This, properly 1 
speaking, is the first state or stage in the life of an 
insect. The forms which distinguish the different 
tribes are numerous and varied ; but none are pro¬ 
vided with wings. They are known in common 
parlance by the names of grub, caterpillar , maggot t 
or wire-worm. All insects in this state feed vora¬ 
ciously, and consequently at this period of their 
lives thqy are the most destructive to vegetation 
They do not feed on all plants alike; some confine 
themselves to one particular species, without which 
they die; others eat the leaves of two or three 
plants only; while some few are general feeders, 
attacking almost every kind of plants without dis¬ 
crimination. Hence it is that the larvae of insects 
found in flower gardens, are different from those of 
the fields, kitchen garden, or orchard. The smaller 
species are generally the most injurious, a^ they 
make use of many curious devices to escape obser¬ 
vation ; some penetrate the heart of the young 
shoot, or eat their way into the bud ; many conceal 
themselves with great skill, by rolling up the 
leaves in which they have taken up their residence ; 
and others, again, spin themselves a silken case, 
where they live in security. 
Of the Pupa or Chrysalis. —This is the second 
state, and here they are not to be dreaded, as in 
general the pupae are torpid, inactive, and incapable 
of receiving nourishment. When the larva has at¬ 
tained its growth, it retires either into the earth, or 
to some secure situation, where the change to the 
chrysalis state is effected in a few hours, or at 
most, a few days. The pupae are as various in 
their forms and situations as the larvae. Those of 
the beetle tribe are found in the earth, or in other 
j substances; they have usually the first rudiments 
of feet, and of other parts, which become fully de¬ 
veloped only in the perfect state. The pupae of 
butterflies are entirely naked; and are either sus¬ 
pended by the tail, or attached to trees, walls, &c., 
by a strong thread. The duration of the chrysalis 
varies according to the species ; and there are many 
insects which undergo so trifling a change, that it 
is scarcely perceptible. 
Of the Imago or Winged Form. —This is the 
third and last stage in the life of an insect, and the 
one in which the organs are fully developed, and 
when it becomes a perfect being, exhibiting those 
characters which point out its station in nature. 
The habits and economy of perfect insects, no less 
than their external appearance, are, in most cases, 
totally different from those which belong to the 
previous stages of their existence. The caterpillar, 
furnished with strong jaws for devouring foliage, 
is changed into an insect, without any organs for 
mastication, and which lives only by sucking the 
nectar of flowers. The duration of this state of the 
insect is also variable. Most are probably annual, 
coming from the egg and passing through all their 
changes within the year. Some, however, as some 
of the beetle tribe, are long-lived. Moths are bi¬ 
ennial, passing the winter in the chrysalis state 
under ground. Butterflies are mostly annual; 
although some few survive the winter, and appear 
early in the spring. Tke perfect insect of some 
species exists but a few hours, and seems born only 
I to provide for a continuation of the species ; while 
I in the lower state it enjoys an aquatic existence of 
* two or three years. L. T. T. 
