INTRODUCTION. 5 



The fnll-fod maggot, lliat has rioted in filth till its lender 

 skin seems ready to burst with repletion, when the appointed 

 time arrives, leaves the offensive matters it was ordained to 

 assist in removing, and gets into some convenient hole or 

 crevice; then its body contracts or shortens, and becomes egg- 

 shaped, while the skin hardens, and tnrns brown and dry, so 

 that, under this form, the creature appears more like a seed 

 than a living animal-; after some time passed in this inactive 

 and equivocal form, dnring which wonderful changes have 

 taken place within the seed-like shell, one end of the shell is 

 forced off, and from the inside comes forth a buzzing fly, that 

 drops its former filthy habits with its cast-off dress, and now, 

 with a more refined taste, seeks only to lap the solid viands of 

 our tables, or sip the licpiid contents of our cups. 



Caterpillars, grubs, and maggots undergo a complete trans- 

 formation in coming to maturity ; but there are other insects, 

 such as crickets, grasshoppers, bugs, and plant-lice, which, 

 though differing a good deal in the young and adult states, are 

 not subject to so great a change, their transformations being 

 only partial. For instance, the young grasshopper comes from 

 the egg a wingless insect, and consequently unable to move 

 from place to place in any other way than by the use of its 

 legs; as it grows larger it is soon obliged to cast off its skin, 

 and, after one or two moultings, its body not only increases in 

 size, but becomes proportionally longer than before, while little 

 stump-like wings begin to make their appearance on the top of 

 the back. After this, the grasshopper continues to eat vora- 

 ciously, grows larger and larger, and hops about without any 

 aid from its short and motionless wings, repeatedly casts off its 

 outgrown skm, appearing each time with still longer wings, 

 and more perfectly formed fimbs, till at length it ceases to grow, 

 and, shedding its skin for the last time, it comes forth a perfectly 

 formed and mature grasshopper, with the power of spreading 

 its ample wings, and of using them in flight. 



Hence there are three periods in the life of an insect, more 

 or less distinctly marked by corresponding changes in the form, 

 powders, and habits. In the first, or period of infancy, an insect 

 is technically called a larva, a word signifying a mask, because 



