94 



INSECTS. 



Sect. III. — Insects. 



An insect is an animal without bones, but covered with a 

 hard skin; it has six or more feet, and breathes through 

 spiracula or pores in the side of the body : yet insects are very 

 different from, and must not be confounded with, vermes or 

 worms. Quadrupeds, birds, and fishes, have all an internal 

 skeleton of bones, to which the muscles are affixed ; but the 

 whole interior of insects is composed of soft flesh, and the 

 muscles are attached to an external shell, w^hich serves the 

 double purpose of skin and bone, and which is completely 

 exemplified in the crab and lobster. 



Another distinguishing criterion of insects is the colour of 

 the circulating fluid or blood, which is never red ; and though 

 a red drop of liquor be obtained from squeezing the animal, 

 it does not appear to be the blood of the animal. The as- 

 sistance of the microscope discovers a circulation, but it is not 

 red. 



The insects and worms hurtful to the farmer are : — 



1. Caterpillars. 



2. Turnip fly, Aphis. 



3. Wire worm. 



4. Snail, or slug. 



Insects are either oviparous, or viviparous ; or the species 

 is perpetuated by their laying of eggs, or by bringing forth 

 their young alive. The former is the general case, there being 

 but few instances of the latter. Insects propagate by laying 

 eggs, in the winged state, from which they rise in the form of 

 caterpillars or worms ; thence into the state of " Chrysalis 

 and lastly into a "fly" state. The fly deposits the eggs in 

 places of safety and of abundance of food. 



1. CATERPILLA.R. — It is the general name of all winged 

 insects, when in the worm state. 



The caterpillars that do damage to cabbages, turnips, and 

 gooseberry bushes, are deposited in the " ovum" state by the 



