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1^ bodr. Th« haMtation of the pupa is usually called Us cocoon ; which term, however, is 

 BWi« eommonly applied to those silken cases or envelopes of which I have been speaking, 

 •ad of which we have an example in the silkworm. This is so closely woven that it ex- 

 ^a^ ^nter, and is often stiffened by a glutinous matter, by which it preserves ils original 

 fbtm e?«i after the perfect animal has escaped : it is also farther strengthened by leaves 

 aad pieeM of wood, which undoubtedly serve as a better protection from its enemies. 

 Thus this helpless state is guartle<l and protected by a system of means which are calculated 

 to secure the existence of the animal in its utterly helpless state ; a state which simulates 

 death, and which, in its ultimate triumph, resembles the resurrection of the body from the 

 pare of real death. 



All in8e«ts do not undergo the same changes ; neither are they alike in analogous states. 

 Thaa the caterpillar of our butterflies wraps itself in its mantle, where it silently under- 

 goat its change ; but the grasshopper comes from the egg an immature insect, but w ith the 

 gmeral form of the perfect animal, and hops about with the rudiments of w^ings upon its 

 baek. As it grows rapidly, it outgrows its skin, which it frequently casts, like the larva of 

 the butterfly : its wings continue to grow, and the body to increase ; the partial wings 

 keep pace witli these changes, till at last they are perfected, and the animal has reached 

 ita perfect state without having lost its activity during its period of growth. The grass- 

 hopper, then, never passes into the inactive pupa state ; and in this its metamorphosis is 

 similar to hugs, and dissimilar to beetles and caterpillars. 



There is another Hifferenre in the history of insect life, which is interesting : it is not 

 the inhabitant of the same medium through life. It may begin its career in the water, and 

 and it in the air : the musqulto is an example. Who has not observed the wiggler in 

 stagnant water, and in our cisterns 1 It is the musquito enjoying its water-life to the full. 

 When the time arrives for its change, it rises to the surface, bursts its mantle, thrusts up 

 its head and spreads its wings, while with its feet it rests still upon its cast-off mantle, then 

 rises buoyant from its sinking bark, and flies away in triumph from the element which 

 gave it birth. 



Equally remarkable are the appetites of the insect in its larva and in its perfect state. 

 Thus the larva, or, as it is usually called, the maggot, sports and feeds upon the putrid 

 mass; but the fly, which springs from its mantle, seeks thehoueyof our table : so vai-ious 

 are the forms and manners of insect life. The caterpillar, grub and maggot go through the 

 three stages, or undergo a complete metamorphosis ; passing through the three periods 

 which are known as the caterpillar, pupa, and imago or perfect stage. The last is the only 

 period which is given them to continue their kind and generations : in many it is transient 

 M the fleeting day, and seems designed only for fulfilling the law of increase ; which, when 

 fulfilled, the insect dies. 



