Insects lay many eggs and reproduce with remarkable rapidity

Insects lay many eggs and reproduce with remarkable rapidity

Insects lay many eggs and reproduce with remarkable rapidity

Insects lay many eggs and reproduce with remarkable rapidity. Their number therefore makes them a foe to be much dreaded. The queen honeybee often lays as many as 4000 eggs in twenty-four hours. A single house fly lays between 100 and 150 eggs in one day. The mosquito lays eggs in quantities of from 200 to 400. The white ant often lays 80,000 in a day, and so continues for two years, probably laying no less than 40,000,000 eggs. In one summer the bluebottle fly could have 500,000,000 descendants if they all lived. The plant louse, at the end of the fifth brood, has laid in a single year enough eggs to produce 300,000,000 young. Of course every one knows that, owing to enemies and diseases (for the insects have enemies which prey on them just as they prey on plants) comparatively few of the insects hatched from these eggs live till they are grown.

Do not completely change their form

Do not completely change their form

Do not completely change their form

Some insects, the grasshopper for example, do not completely change their form. Fig. 147 represents some young grasshoppers, which very closely resemble their parents.

Fig. 143. Butterfly

Fig. 144. Structure of the Caterpillar

Fig. 145. Moth Pupa in Cocoon

Fig. 146. A Butterfly Pupa
Note outline of the butterfly

Fig. 147. The Growth of a Grasshopper

It is generally the larvæ that do the most harm

It is generally the larvæ that do the most harm

It is generally the larvæ that do the most harm

From this you can see that it is especially important to know all you can about the life of injurious insects, since it is often easier to kill these pests at one stage of their life than at another. Often it is better to aim at destroying the seemingly harmless beetle or butterfly than to try to destroy the larvæ that hatch from its eggs, although, as you must remember, it is generally the larvæ that do the most harm. Larvæ grow very rapidly; therefore the food supply must be great to meet the needs of the insect.

Fig. 142. Moth and Cocoon

The egg hatches into a worm-like animal known as a grub

The egg hatches into a worm-like animal known as a grub

The egg hatches into a worm-like animal known as a grub

Many insects change their form from youth to old age so much that you can scarcely recognize them as the same creatures. First comes the egg. The egg hatches into a worm-like animal known as a grub, maggot, or caterpillar, or, as scientists call it, a larva. This creature feeds and grows until finally it settles down and spins a home of silk, called a cocoon (Fig. 145). If we open the cocoon we shall find that the animal is now covered with a hard outside skeleton, that it cannot move freely, and that it cannot eat at all. The animal in this state is known as the pupa (Figs. 145 and 146). Sometimes, however, the pupa is not covered by a cocoon, sometimes it is soft, and sometimes it has some power of motion (Fig. 141). After a rest in the pupa stage the animal comes out a mature insect (Figs. 142 and 143).

It is important to know how insects take their food

It is important to know how insects take their food

It is important to know how insects take their food

It is important to know how insects take their food, for by knowing this we are often able to destroy insect pests. Some are provided with mouth parts for chewing their food; others have a long tube with which they pierce plants or animals and, like the mosquito, suck their food from the inside. Insects of this latter class cannot of course be harmed by poison on the surface of the leaves on which they feed.

Fig. 141. Beetle
a, larva;
b, pupa;
c, adult;
d, burrow

The chief classes of insects are as follows

The chief classes of insects are as follows

The chief classes of insects are as follows

The chief classes of insects are as follows: the flies, with two wings only; the bees, wasps, and ants, with four delicate wings; the beetles, with four wings—two hard, horny ones covering the two more delicate ones. When the beetle is at rest its two hard wings meet in a straight line down the back. This peculiarity distinguishes it from the true bug, which has four wings. The two outer wings are partly horny, and in folding lap over each other. Butterflies and moths are much alike in appearance but differ in habit. The butterfly works by day and the moth by night. Note the knob on the end of the butterfly's feeler (Fig. 143). The moth has no such knob.

Fig. 140. A Typical Bug
a, adult;
b, side view of sucking
mouth-part Both a and b
are much enlarged

Therefore these do not belong to the true insects

Therefore these do not belong to the true insects

Therefore these do not belong to the true insects

An examination of spiders, mites, and ticks shows eight legs; therefore these do not belong to the true insects, nor do the thousand-legged worms and their relatives.

Fig. 139. The House Fly
a, egg;
b, larva, or maggot;
c, pupa;
(All enlarged)

Fig. 139a. The House Fly
adult male. (Enlarged)

The eyes of insects are especially noticeable

The eyes of insects are especially noticeable

The eyes of insects are especially noticeable

The eyes of insects are especially noticeable. Close examination shows them to be made up of a thousand or more simple eyes. Such an eye is called a compound eye. An enlarged view of one of these is shown in Fig. 138.

Attached to the thorax are the legs and also the wings, if the insect has wings. The rear portion is the abdomen, and this, like the other parts, is composed of parts known as segments. The insect breathes through openings in the abdomen and thorax called spiracles (see Fig. 137).

Every one thinks he knows what an insect is

Every one thinks he knows what an insect is

Every one thinks he knows what an insect is

Every one thinks he knows what an insect is. If, however, we are willing in this matter to make our notion agree with that of the people who have studied insects most and know them best, we must include among the true insects only such air-breathing animals as have six legs, no more, and have the body divided into three parts—head, thorax, and abdomen. These parts are clearly shown in Fig. 136, which represents the ant, a true insect. All insects do not show the divisions of the body so clearly as this figure shows them, but on careful examination you can usually make them out. The head bears one pair of feelers, and these in many insects serve also as organs of smell and sometimes of hearing. Less prominent feelers are to be found in the region of the mouth. These serve as organs of taste.

Fig. 137. Parts of an Insect

Fig. 138. Compound Eye
Of Dragon Fly

Insects in General

Insects in General

Fig. 136. Ants

The farmer who has fought "bugs" on crop after crop needs no argument to convince him that insects are serious enemies to agriculture. Yet even he may be surprised to learn that the damage done by them, as estimated by good authority, amounts to millions and millions of dollars yearly in the United States and Canada.

Often attacks the unripe fruit on the tree

Often attacks the unripe fruit on the tree

Often attacks the unripe fruit on the tree

Fruit Mold. Fruit mold, or brown rot, often attacks the unripe fruit on the tree, and turns it soft and brown and finally fuzzy with a coat of mildew. Fig. 133 shows some peaches thus attacked. Often the fruits do not fall from the trees but shrivel up and become "mummies" (Fig. 134). This rot is one of the most serious diseases of plums and peaches. It probably diminishes the value of the peach harvest from 50 to 75 per cent. Spraying according to the directions in the Appendix will kill the disease.

Fig. 135. Half of Tree sprayed to prevent Peach Curl

Note The Difference in Foliage And Fruit on The Sprayed And Unsprayed Halves of The Tree, And The Difference in Yield Shown Below

Peach leaf curl does damage amounting to about $3

Peach leaf curl does damage amounting to about $3

Peach leaf curl does damage amounting to about $3

Peach Leaf Curl. Peach leaf curl does damage amounting to about $3,000,000 yearly in the United States. It can be almost entirely prevented by spraying the tree with Bordeaux mixture or lime-sulphur wash before the buds open in the spring. It is not safe to use strong Bordeaux mixture on peach trees when they are in leaf.

Cotton Wilt. Cotton wilt when it once establishes itself in the soil completely destroys the crop. The fungus remains in the soil, and no amount of spraying will kill it. The only known remedy is to cultivate a resistant variety of cotton or to rotate the crop.