490 



THE CENTURY BOOK OF GARDENING. 



pair of wings, and in others there are mine at all, but there are always six legs. 

 It has now attained its full size, and does not grow any larger ; it should always 

 he remembered, therefore, that a small beetle never grows into a large one, or a 

 small fly into a bluebottle, but, as they come out of the chrysalis, so they remain, after 

 they have stretched their limbs. Though a typical perfect insect has two pairs of wings and 

 three pairs of legs, some insects (flies, for instance) have only one pair of wings, and others 

 have none, while beetles and earwigs have only one pair that they can use for flight, the 

 other pair forming wing coverings or cases. All, however, have six legs. All perfect 

 insects are formed in three divisions, which are usually very easy to distinguish — namely, the 

 head, the thorax or fore body, and the body or abdomen. The head carries the feelers or 

 antennae, the mouth organs, and eyes; the thorax bears the legs and wings; and the body 

 contains the digestive and other internal organs. Although spiders, mites, millipedes, 

 centipedes, and woodlice are commonly spoken of as insects, they are not so really, as 

 they do not undergo well-marked transformations ; they never have wings, have always 

 more than six legs, and are not composed of three easily distinguished divisions. 



Insects do not breathe through their mouths, or by the aid of gills, as so many 

 animals do, but by means of a series of pores that are on either side of their thorax or 

 abdomen. These pores are easily seen in any large caterpillar as a row of dark dots just 

 above the legs, and communicate with a series of air tubes which permeate the insect in 

 all directions, carrying the air to all parts of the body, so as to ensure a proper supply of 

 oxygen to the blood. The chief organ connected with the circulation of the blood is a 

 long vessel, which may, I suppose, be called the heart. It is situated near the back of the 

 insect, and forces the blood into the head, whence it returns, flowing among all the 

 different internal organs. It comes into contact with the various air tubes, and eventually 

 finds its way into the heart again. The blood is usually colourless, but is sometimes 

 yellowish or reddish. It is well to bear these facts in mind, as it is the position of the 

 breathing pores at the sides of the insects that mikes it so desirable in the case of 

 many insects — green fly, for instance — to add soft soap to any wash that may be used to 

 destroy them, as the soap forms a coating over the insect, which closes the breathing pores 

 and the insect is stifled. It is also well to remember that there are two quite different kinds 

 of mouths among insects, for some bite and can eat the leaves, flowers, and shoots, and 

 can even bore into hard wood, others can only suck the juices of plants, while others again 

 can both bite and suck. Those that bite, such as beetles, grasshoppers, earwigs, and 

 caterpillars, may be killed by covering their food with some poisonous substance. Those 

 that can only suck', aphides, plant bugs, and froghoppers, for instance, cannot be killed in 

 this manner, as it is impossible to introduce poison into the sap of plants. 



PREVENTING INSECT ATTACKS. — Though it is most desirable when possible to use 

 certain means to destroy the insects while attacking the plants, it is even more useful to 

 take steps to prevent the attack being made, and a j^reat deal may be done in this way by 

 taking a few precautions. Never allow weeds to grow in a garden (this is perhaps easier said 

 than done), as all plants have insects that feed on them, and these frequently leave the 

 weeds for the cultivated plants ; odd corners, covered with grass and weeds, should be dug 

 up and kept tidy, otherwise they are a perfect paradise for insects to breed in unmolested. 

 Nothing in the way of stones or rubbish of any kind should be allowed to remain on the 

 beds or near any plant, as various insects are very fond of hiding under them. The refuse 

 of all crops or plants that have been infested with any insect or fungus should never be 

 put on the rubbish heap, as these pests will often come to maturity there, nor should they be 

 allowed to lie about on the ground on which the crop has grown, but they should be burnt 

 immediately. When trees or shrubs are pruned it is always safer to burn the primings, as 

 there are often eggs of insects upon them. The chrysalides of many insects are formed in 

 the ground, and these should always be looked for when garden ground is being dug up. When 



