INSECTS, FUNGI, PLANT DISEASES, ETC. 107 



CHAPTER VIII. 



INSECTS, FUNGI, PLANT DISEASES — SPRAYING APPARATUS 

 AND METHODS. 



No plant, no part of a plant is exempt from the attacks 

 of insects. One devours its tender leaf as it issues from 

 the ground; another preys upon the root, and the plant 

 perishes; another burrows into the stem, boring it in 

 every direction until the stem is broken off by the wind. 

 The caterpillar preys upon the leaves when the plant gets 

 more mature, while the black grub cuts off the young 

 plant just as it is shooting into growth. Some feed upon 

 the flowers, while others devour the matured fruit or 

 seed. 



Insects are on the increase in American gardens, partly 

 from the fact that the destruction of forest trees and wild 

 plants has driven them to the cultivated ones for food 

 (the apple-tree borer, for instance, originally subsisting 

 on the thorn), partly from being constantly imported from 

 all other countries from which seeds and plants are 

 brought, and partly from the diminution of birds and 

 other enemies by which they are naturally held in check. 



Insects are a most extensive class of animals. They 

 are destitute of an internal skeleton, but possess a sort of 

 external one, serving both for skin and bones, and divided 

 into numerous segments connected together by slender 

 points of attachment. They all have six or more articu 

 lated legs, and are generally oviparous, or produced from 

 eggs. They possess sight, hearing, smell, and touch at 

 least — senses in common with those of the superior ani- 

 mals. They do not breathe through the mouth or nostrils, 

 but through vessels for the reception of air, called spirac- 

 ula, placed along each side of the body. 



