SOO CLASS V. INSECTS. 



to keep them steady, and, in some measure, counteract 

 the changes of the air, which otherwise might waft them 

 along in its current. If one of those balances is cut off, 

 the insect loses its equipoise, and falls to the ground ; if 

 both are removed, it will still continue to fly, though 

 subject to the direction of every breeze. 



Insects, as far as is yet known, are generated, like the 

 larger animals, from eggs ; and these are at first inclosed in 

 a single or double covering, which opens when the nascent 

 animal has arrived at a proper stage of maturity. When 

 the young break their shell at once, as the millipedes, 

 the parents are said to be viviparous ; but, when the em- 

 bryo is wrapped up in a covering, in which it is destined 

 to remain for some time, as the silk-worm, they are 

 called oviparous. 



The instinct displayed by the oviparous kinds, in depo- 

 siting their eggs in a suitable situation, where they may 

 meet with the requisite heat, or the young animal, when 

 first produced, may find the most appropriate nourish- 

 ment, is not the least extraordinary circumstance attending 

 them. No insects abandon their eggs to chance ; nor do 

 they ever err in respect to the situation to be chosen for 

 the purpose of bringing them to life. Caterpillars, which 

 eat oleraceous plants, are never found on willows ; nor 

 such as eat willows, on cabbages. Moths delight to lodge 

 among woollen stuffs or papers, but none take up their 

 residence on plants or in mud. Thus, instinct in insects 

 is as powerful as reason in man, as far as self-preservation, 

 and the care for posterity, are concerned. 



When the eggs of some kinds are hatched, the young 

 appear in their perfect and permanent shape; but the 

 greater number of insects pass through different stages of 

 existence, and successively assume the figure of two or 

 three animals, which bear no resemblance to each other. 

 From the eggs of the gnat proceed animalcules which first 

 live in the water, then become amphibious, and are at last 

 inhabitants of the air. 



Summer which developes, in the most powerful manner, 



