4 INSECTS INJURIOUS TO VEGETATION. 



their bodies till the young are ready to escape. Others inva- 

 riably lay their eggs where their young, as soon as they arc 

 hatched, will find a plentiful supply of food immediately within 

 their reach. 



Most insects, in the course of their lives, arc subject to very 

 great changes of form, attended by equally remarkable changes 

 in their habits and propensities. These changes, transforma- 

 tions, or nieUunorphoscs, as they are called, might cause the 

 same insect, at different ages, to be mistaken for as many 

 different animals. For example, a caterpillar, after feeding 

 upon leaves till it is fully grown, retires into some place of 

 concealment, casts off its caterpillar-skin, and presents itself in 

 an entirely different form, one wherein it has neither the power 

 of moving about, nor of taking food; in fact, in this its second 

 or chrysalis state, the insect seems to be a lifeless oblong oval 

 or conical body, without a distinct head, or movable limbs ; 

 after resting awhile, an inward struggle begins, the chrysalis- 

 skin bursts open, and from the rent issues a butterfly, or a moth, 

 whose small and flabby wings soon extend and harden, and 

 become fitted to bear away the insect in search of the honeyed 

 juice of flowers and other liquids that suffice for its nourishment. 



The little fish-like animals that swim about in vessels of 

 stagnant w^ater, and devour the living atoms that swarm in the 

 same situations, soon come to maturity, cast their skins, and 

 take another form, wherein they remain rolled up like a ball, 

 and cither float at the surface of the water, for the purpose of 

 breathing through the two tunnel-shaped tubes on the top of 

 their backs, or, if disturbed, suddenly uncurl their bodies, and 

 whirl over and over from one side of the vessel to the other. 

 In the course of a few days these little water-tumblers are 

 ready for another transformation; the skin splits on the back 

 between the breathing-tubes, the head, body, and limbs of a 

 mosquito suddenly burst from the opening, the slender legs 

 rest on the empty skin till the latter fills w^ith water and sinks, 

 when the insect abandons its native element, spreads its tiny 

 wings, and flies away, piping its ^var-note, and thirsting for 

 the blood which its natural weapons enable it to draw from its 

 unlucky victims. 



